US3596678A

US3596678A - Valve actuator manifold for a return flow oil burner system

Info

Publication number: US3596678A
Application number: US8348A
Authority: US
Inventors: Nick Kutrubs; Michael Panich; Lino Perossa; Jack F Shannon
Original assignee: Bailey Meter Co
Current assignee: Elsag Bailey Inc
Priority date: 1970-02-03
Filing date: 1970-02-03
Publication date: 1971-08-03
Anticipated expiration: 1988-08-03
Also published as: CA921388A

Abstract

An apparatus, for lighting-off, maintaining fire on and shutting-down one or more oil burners, having a plurality of valves independently biased in the closed direction and mounted in a base. The plurality of valves form first and second valve banks adapted to be alternatively actuated by a plurality of crank arms locked to a drive shaft which is journaled for rotation through a predetermined angle plus and minus of a reference position. A manual-automatic controller, having a handwheel drive and an electric motor drive for alternative control modes, rotates the drive shaft to open and close the valves. In the automatic mode the electric motor is energized by a logic system to turn the burner on, off or trip, and the motor is deenergized when switches associated with preselected valves indicate that a predetermined position of the valves has been obtained.

Description

United States Patent [72] Inventors Nick Kutrubs Cleveland; Michael Panich, Willoughby; Lino Perossa, Willoughby; Jack F. Shannon, Euclid, all of, Ohio [211 App]. No. 8,348 [22] Filed Feb. 3, 1970 [4S] Patented Aug. 3, 1971 [73] Assignee Bailey Meter Company [54] VALVE ACTUATOR MANIFOLD FOR A RETURN FLOW 01L BURNER SYSTEM 1 1 Claims, 8 Drawing Figs.

[52] US. (I l37/624.18, 137/607, 137/628, 137/599.1, 137/637.1 [51] hit. F23d 11/28, F161: 1 H00 [50] Field olSearch ..l37/624.l8, 624.2, 628, 599.1, 637.1, 607, 606, 240

[56] References Cited UNITED STATES PATENTS 2,464,998 3/1949 Stevens 137/624. 1 8 X 3,211,013 10/1965 Quesinberry Primary ExaminerAlan Cohan AttorneyJ0hn F. Luhrs ABSTRACT: An apparatus, for lighting-off, maintaining fire on and shutting-down one or more oil burners, having a plurality of valves independently biased in the closed direction and mounted in a base. The plurality of valves form first and second valve banks adaptedto be alternatively actuated by a plurality of crank arms locked to'a drive shaft which is journaled for rotation through a predetennined angle plus and minus of a reference position. A manual-automatic controller, having a handwheel drive and an electric motor drive for alternative control modes, rotates the drive shaft to open and close the valves. In the automatic mode the electric motor is energized by a logic system to turn the burner on, off or trip, and the motor is deenergized when switches associated with preselected valves indicate that a predetermined position of the valves has been obtained.

PAIENTEU AUG 3 I97:

sum 1 BF 6 EN E 5N n22 82 mm? EmsZIQ 2253200 PATENTED AUG 3 l97l SHEET 2 OF 6 FIG. ,2

INVEN'I'ORS NICK KUTRUBS MICHAEL PANICH UNO. PEROSSA PATENTEU AUG 3197! SHEET 3 OF 6 ASG FIG. 3

1N VENTORS NICK KUTRUBS MICHAEL PANICH BY LINO PEROSSA JAC F. 5%

FIG. 4a

PATENTEU AUG 3E]?! 3,596,678

SHEET '4 OF 6 INVENTORS NICK KUTRUBS lG MICHAEL PANICH BY LINO PEROSSA JACK F. SHANNON 5M. fxd

PAIENIEDAIIBGIQII 3.596678 SHEET 5 OF 6 |Oc1 Q) O\ OIL To BURNER A OIL FROM B V BURNER 26NB DR lgN 26AM I RETURN OIL SUPPLY l OUTPUT sTEAM INPUT FROM VALVE To VALVE MANIFOLD MANIFOLD 265C V SUPPLY OIL INPUT TO VALVE MANIFOLD 26PV y 6MN P O ,/A57 57 l I I 5 B84 /A84 64 TO/FROM SYSTEM 3 CONTROL LOGIC I26 l t I22 I I SYSTEM LOGIC MOTOR /P57 TERMINAL 4o 5 36 I28 M INVEN'I'ORS FIG. 6

NICK KUTRUBS MICHAEL PANICH LINO PEROSSA JACK F. SHANNON VALVE ACTUATOR MANIFOLD FOR A RETURN FLOW OIL BURNER SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to apparatus for starting-up, maintaining and shutting down an oil burner, and, more particularly, to a valve actuator manifold for alternatively supplying oil and steam to a burner in a return flow oil burner system.

The invention is particularly applicable to an automatic or remotely controlled valving arrangement for a return flow oil burner system wherein supply oil is diverted from the burner through a bypass valve, when a burner is shut down, to maintain a steady flow of oil in the system and will be described with particular reference thereto although it will be appreciated that the invention has broader applications such as in any oil burner system utilizing a plurality of valves some of which are to be actuated alternatively.

2. Description of the Prior Art valving arrangements for return flow oil burners have heretofore comprised an oil supply header valve and an oil return header valve communicating oil to and from a burner at a predetermined rate of flow. The oil burned is a function of the differential oil pressure at a burner nozzle, and the differential pressure is primarily controlled by adjusting the return header valve. The inclusion of a supply header valve provides an additional oil pressure adjustment.

On large boilers, multiple burners are employed, and the desired steaming rate is maintained by adding or subtracting burners or groups of burners from service as conditions may require. In order to facilitate the lighting off, maintainingfire on and shutting down of burners, a valving arrangement for supply and return oil is necessary at each burner or at each group of burners designed to operate in unison. This valving arrangement should provide for purging the supply and return lines to and from the burner or group of burners with steam when the burner or group of burners has been shutdown in order to protect against coking of the residual oil and subsequent clogging of the burner nozzle under the catalytic action of furnace heat. In addition, the valving arrangement should also provide for cooling the nozzle of the burner with steam when the burner is shut down. Provision should also be made for draining any oil leaked into the steam supply system of valves and lines while the burner is lighting off or is in a firing operation and for draining any condensed steam that may freeze and block the passages or cause damaging water hammers.

Another feature that the valving arrangement should provide is an oil bypass valve which communicates oil between the oil supply header valve and the oil return header valve when the respective burner or group of burners is not being tired in order to maintain steady oil flow in the system regardless of the number of burners in service. The inclusion of this bypass valve in the valving arrangement should additionally provide that the oil in the lines near the burner, from the oil supply header valve and to the oil return header valve, are kept warm and clear when the burner is not in service.

Valve arrangements of the type to which this invention pertain have ordinarily included some valves of the lubricated plug cock design which are widely used for manually operated burner applications. This type of valve has a plug-travel versus seat opening characteristic such that the plug must rotate approximately one-third of its total travel before the flow area through the seat opening begins to be exposed.

The principal problems with this type of valve are that they require frequent lubrication to maintain tight seating and smooth positioning and that when the seat just begins to open, the flow capacity is a large percentage of the fully open flow capacity. This latter characteristic has caused severe oil pressure fluctuations in the transient period of valve actuation during burner light ofi or valve closure during burner shutdown.

The pressure fluctuations are undesirable because they can af fect the operation of the other burners in service, e.g. cause loss of flame, and this can produce an unsafe condition.

The present invention contemplates new and improved apparatus which overcomes all of the above referred problems and others and provides a valve actuator manifold for a return flow oil burner system which is compact, simple, requires a minimum of maintenance and insures maximum reliability.

SUMMARY OF THE INVENTION In accordance with the present invention, a valve actuator manifold of the type having the described functions is provided, comprising: a base having a central axis and a plurality of spaced apertures with some of the apertures forming aperture pairs, each pair having one aperture on either side of the central axis located on an axis perpendicular to the central axis; a plurality of valves independently biased in the closed direction, the valves being mounted in theba'se with some of the valves forming a first valve bank on one side of the central axis and the other valves forming a second valve bank on the other side of the central axis, each of the valves having a valve stem which is adapted to actuate the valve through the apertures associated therewith in the base; a drive shaft journaled for rotation through a predetermined angle plus and minus of a reference position, the shaft being joumaled along an axis parallel to the central axis of the base; a plurality of crank arms spaced along the drive shaft and locked thereto, each of the crank arms projecting perpendicular from the journal axis of the drive shaft with each crank arm embracing at least one of the valve stems to actuate the valve upon rotation of the drive shaft; means for interconnecting the inputs and outputs of the plurality of valves to oil and steam sources and returns for the burner; and, means for controlling the angular position of the drive shaft to'altematively actuate the first and second valve banks to supply the burner with oil and steam for lighting off, maintaining fire on and shutting down the burner.

Further, in accordance with the invention, a valve manifold as described above is provided wherein each valve includes a spring to close bias assembly comprising: a valve stem extension secured to the valve stem, the stern extension having exterior threads; a stem plate having interior threads threaded over the extension, the stern plate being lifted by the crank arm to open the valve; and, means for locking the stem plate to the extension at substantially any point on the threaded portion of the stem extension so that the valve is stroked open in a predetermined sequence with respect to the other valves.

Further, in accordance with the invention, a valve manifold as described above is provided wherein the first valve bank includes an oil supply valve and an oil return valve to communicate oil to and from the burner when the first valve bank is actuated, the oil supply valve and the oil return valve including first means for signalling the control means when both of the valves reach a predetermined position.

Still further, in accordance with the invention, a valve manifold as described above is provided wherein the second valve bank includes a steam supply valve, a pair of steam valves to communicate variable pressure steam from the steam supply valve to the burner when the second valve bank is actuated, and an oil bypass valve to shunt oil passed the first valve bank when the second valve bank is actuated, the oil bypass valve also being adapted to shunt oil passed the first valve bank when all of the remaining valves of the plurality are closed, the steam supply valve including second means for signalling the control means when both the steam supply valve and the oil supply valve reach a predetermined position.

The invention also provides for the integration of valves, into the above described valve manifold, having various valve plug characteristics so as to maximize a smooth transition between supply and return oil in lighting off the burner and the minimize oil pressure fluctuations in the return flow oil burner system.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic illustration of a return flow oil burner system incorporating a valve arrangement for a burner or a group of burners.

FIG. 2 is a front elevational view, partially in section, of one embodiment of the valve assembly according to the invention.

FIG. 3 is a side elevational view, partially in section, of the valve assembly.

FIG. 4 is a back elevational view, partially in section, of the valve assembly.

FIG. 4a is a partial cross section taken along the line 4a-4a in FIG. 4.

FIG. 5 is a bottom plan view of the valve assembly showing the input and output connections for oil and steam.

FIG. 6 is an electrical schematic illustration showing the interrelationships of the travel limit signal switches for the valve assembly.

FIG. 7 is a graphical representation of the valve characteristics for the valve assembly showing valve openings as a function of both valve stem travel and time.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1 of the drawings, a valve manifold assembly 10a is interposed between an oil burner 12a for supplying oil through a nozzle 13a to a combustion chamber 14 of a furnace and a plurality of

headers

15, 19 and 22. The designation 12a also represents a group of oil burners designed to operate in unison such as in a cell burner known to those skilled in the art. An oil supply header 15 provides oil to the oil burner 12a through the valve manifold assembly 10a by way of an input connection to a manifold tee 26AC. An oil supply header valve 16 is connected to the oil supply header 15 in order to set the fuel oil pressure supplied to the oil burner 12a. A plurality of tees 17b, 17c, l7n are interposed between the valve 16 and the manifold tee 26AC in order to supply fuel oil to the other burners or groups of burners in the system on oil supply lines 15B], 15C], and 15Nl, respectively. Two

additional oil burners

12b, 120 having

respective nozzles

13b, 13c directed into the combustion chamber 14 are shown in FIG. 1, and it should be understood that these oil burners have valve manifolds similar to that shown within 10a and supplied by oil lines ISBl, ISCI, respectively. The

designations

12b, 120, like 12a, also represent groups of oil burners of known design.

An oil return line 19A3 is connected to the valve manifold 100 at a manifold tee 268C in order to return the fuel oil not burned at oil burner 12a to the oil return header 19. The oil return from the other burners in the system is similarly accomplished by way of oil return lines 1983, I9C3, 19N3 and oil return tees 21b, 21c, 21, respectively. An oil return header valve is interposed between the oil return lines and the oil return header 19 in order to adjust the pressure of the fuel oil returned so that by an adjustment of

valves

16 and 20, the fuel oil pressure differential to the

oil burners

12a, 12b, 12c, and the other burners in the system is properly set. The pressure varies with load requirements, and is primarily controlled by adjusting the return header valve 20. The fuel oil pressure at the burner nozzles is typically within the range of 400 to 1000 p.s.i.g. for minimum to maximum load requirements.

The valve manifold assembly 10:: includes an oil supply valve A and an oil return valve B, both of which must be open when the oil burner 12a is in operation to supply fuel oil to the combustion chamber 14. For convenience, the condition of valve operation to supply fuel oil to the combustion chamber will be referred as BURNER ON, and when this condition exists, the flow of fuel oil in supply line 15A! is into manifold tee 26AC, through oil supply valve A, through line 15A2 and manifold tee 26AM, out of valve manifold 10a and into oil burner 12a through line HAS to inject the fuel oil through the nozzle 13a into the combustion chamber 14. The excess fuel oil from the oil burner 12a is returned on line 19A] into the valve manifold 10a through a manifold tee 26NB, through line I9A2 and oil return valve B, through the manifold tee 26BC and out of the valve manifold through oil return line 19A3.

Another valve included in the valve manifold assembly 10a is the oil bypass valve C which is connected between the manifold tees 26AC and 26BC by oil lines 15Al and 19A3. The valve C is'fully closed when valves A and B are open corresponding to the BURNER ON condition of operation. Valve C is included in the valve manifold 10a for the purpose of optimizing firing rate control by maintaining system oil flow steady regardless of the number of burners in service. This optimization is provided by causing valve C to become fully opened, so that the pressure drop across it will approximate the combined manifold assembly and burner pressure drop, when fuel oil flow to the oil burner 12a is shut off corresponding to the fully closed position of valves A and B. This condition will be referred as BURNER OFF. The inclusion of valve C also provides that there is a continuous flow of fuel oil in the oil supply line 15A1 and the oil return line 19A3, respectively leading to and from the valve manifold 10a, during the time that the oil burner 12a is out of operation. The continuous flow of fuel oil through line 15Al, through valve C and through line I9A3 keeps the oil supply and return lines warm and clear when a burner is not in service. It should be recognized that this feature is included for each of the valve manifolds interposed between the

other oil burners

12b, 12c and their respective oil supply lineslSBl, 15C1 and oil return lines 19B3, 19C3.

The system illustrated in FIG. 1 also includes a valve arrangement for the purpose of purging and cooling lines 15A3 and I9AI when the oil burner 12a has been shut down corresponding to the BURNER OFF condition. In order to accomplish the purging and cooling function, the valve manifold assembly 10a includes a steam supply valve P and a pair of steam valves M and N. The steam supply valve p is connected to a steam supply header 22 on a steam supply line 22Al. A steam supply header valve 24 and a steam pressure indicator 23 is interposed between the steam supply header 22 and line 22Al for the purpose of adjusting the steam pressure to the most effective values for purging and cooling. The header valve 24 includes a steam pressure regulator 25 with an adjustable set point which can be automatically changed to maintain the steam pressure output from valve 24 at a first predetermined level for purging and at a second predetermined level, usually lower than the first level, for cooling. A bypass valve arrangement of valves in line 22A1 can also be used to independently adjust the steam pressure to the most effective values. A plurality of

steam supply tees

23b, 23c, 23n are connected in the steam supply line 22Al in order to supply purging and cooling steam on lines 22B1 22Cl 22Nl respectively, through the associated valve manifolds to the other oil burners in the system. The valves P, M, N are concurrently opened after valves A and B are fully closed and valve C is still opening further.

The flow of either purging or cooling steam follows the course of the dashed arrows through the valve manifold 10a along the path through the steam line 22A1 and valve P, through lines 22A2, through manifold tees 26PV and 26MN dividing toward valves M and N and lines 22A3 and 22A4 respectively. The steam is output from the valve manifold 10a through the tee 26AM and forces the fuel oil entrapped in the line 15A3 and the oil burner 12a out of the nozzle 13a into the combustion chamber 14 to purge the oil when the valves are positioned in the BURNER OFF condition. Similarly the steam forces the fuel oil entrapped in the lines 22A4 and 19A] and the oil burner 12a out of the system. The steam purge of the system can be accomplished at a pressure of I p.s.i.g., and this will insure against coking and subsequent clogging of the oil supply lines, oil burner 12a and nozzle 130 when the burner is initially turned off. Cooling steam at a pressure of 60 p.s.i.g. can be applied, through the same route as the purge steam, after the system has been purged in order to cool the lines 15A3, 19Al, the oil burner 12a and nozzle 130 while in the BURNER OFF condition. These values of purge pressure and cooling pressure are typical, and any pressure sufficient to accomplish these functions may be used instead. This cooling steam is supplied to the system when the burner nozzle 13a is retracted from the firing position, and this insures that the oil burner 12a and nozzle 13a will be kept sufficiently cool to prevent coking upon a subsequent firing of the burner.

The valve manifold assembly 104 also includes a drain valve V connected between the manifold tee 26PV and a drain line 22AV. The purpose of valve V is to drain any leakage of fuel oil from valves M and N during the time that valves A and B are open corresponding, to the BURNER ON condition, and also while the burner is being shut down. The V valve also serves to drain any steam or its condensate in lines 22A2 from previous purging or cooling. The valves B and V begin to open and fully close concurrently; valve A precedes the opening and closing of valves B and V by a predetermined time interval. This delay insures that valve A will be open for a time interval before valve B has begun to open in order to allow the supply oil to reach the oil burner before return oil. This interval is adjustable, according to the invention, and may typically be on the order of 0.5 seconds.

Referring now to FIGS. 2, 3 and 4 showing a front elevational view, and a back elevational view, respectively, of a preferred embodiment of the invention, the valve manifold assembly 10a appears in the lower portion of each of each of the figures. Each of the valves A, B, C, M, N, P and V are mounted in a baseplate 30 by means of respective valve bonnets A56, B56, C56, M56, N56, P56 and V56. It may more clearly be seen with reference to FIG. that the valves A, B and V are aligned form a first valve bank along one side of the baseplate 30 and the valves M, C, N and are aligned to form a second valve bank on the other side of baseplate 30. The manifold tees within the valve manifold a of FIG. 1 are correspondingly designated in FIGS. 25 with the same alphanumeric characters.

Again referring to FIG. 2, the valve actuator manifold of the present invention includes the valve manifold assembly 1011 mounted below the baseplate 30, a valve actuator assembly 32 mounted above the baseplate 30 and a manual-automatic controller 34 mounted above the valve actuator assembly 32. The valve manifold assembly 104 can also be cast in a unitary block formed with manifold passages and the valves mounted therein. Such an arrangement would provide additional savings in space and weight over previous arrangements. Since the unitary block manifold arrangement is equivalent in function to the assembly described herein and the details for its construction are within the skill of one in the art, it will not be further described herein.

The controller 34 includes a gear train and a system logic terminal within 36, connected to a system control logic (not shown), for controlling the actuation of all the valves. The system control logic is generally remotely located in a master control room. A shaft 39 is geared to the gear train within 36, and a declutchable handwheel 38 is locked to shaft 39 in order to provide manual control. An induction motor 40 is mounted to mechanically couple with the gear train 36, and it is electrically-coupled to the system logic terminal therein by a wire conduit 42. A position indicator 44 projects from the top of the controller 34 as can be clearly seen in FIG. 3, and this indicator 44 is used to shown whether the first and second bank of valves is stroked for BURNER ON, BURNER OFF or an intermediate TRIP condition. The designation TRIP condition as used herein is that state of the valves when valve C is open and all other valves in the manifold are closed to prevent steam from purging oil into the combustion chamber while explosive conditions exist.

The valve actuator assembly 32 is kept free of contaminants by means of an actuator cover 46 which is shown partially cutaway in order to expose the interior of the valve actuator assembly 32. The controller 34 is secured to a yoke 48 by means of mounting

screws

45a, 45b, and the yoke 48 is secured to the baseplate 30 by means of mounting

screws

49a, 49b. A ram assembly within the yoke 48 will be subsequently described with respect to FIGS. 3 and 4. The valve actuator assembly 32 includes a plurality of independent bias assemblies designated by the numeral 58 preceded by the alphabetical character corresponding to the respective valve with which it is associated. The valve stem emerging from each respective valve is correspondingly alphanumerically designated with the numeral 57 A pair of bushing blocks 50, 52 are mounted to the baseplate 30, or to the unitary manifold block if such is used, in spaced relationship with respect to the first and second valve banks. The bushing block 50 includes a lubricated bushing 51 and the bushing block 52 includes a lubricated bushing 53 through which a drive shaft 54 is joumaled. The drive shaft 54 is dimensioned to extend from beyond the line joining the stern axis of valves A and M to beyond the stem axis of valves P and V so as to provide the means for actuating each of the valves. The drive shaft 54 is splined at 55 as well as in the regions aligned with each axis joining the opposing sets of valves A-M, B-N and P-V.

With reference to FIG. 3, the valve bias assembly M58 for valve M is shown in partial cross section, and FIG. 3 also more clearly shows the actuator assembly for stroking the first and second valve banks. The valve bias assembly, as well as the valve mounting arrangement is identical for each of the seven valves in the valve actuator assembly 32, and the following description for valve M applies for each bias assembly.

The valve stem M57 is connected by means of screw threads to a valve stem extension 60. A disc-shaped position indicator 6] with a hole through its center is interposed between the shoulder of stem extension 60 and a locknut 62 is threaded on stem M57. The position indicator 61 has an edge proximate to an indicator scale M78 which provides an indication of the relative stroke of the valve M. A portion of the stem extension 60 is threaded near its center to receive a threaded stern plate M64 which may be positioned plus or minus a reference position on the stem extension 60. This serves as an adjustment for the valve as will be described subsequently. A lockwasher 65 and a jam nut 66 threaded on the stern extension 60 lock the stem plate M64 after it has been properly located.

Three mounting

posts

68a, 68b, 680 are screw fastened to an annular mounting plate M63 which is secured to baseplate 30 by a plurality of

screws

63a, 63b as may be seen by referring to FIG. 2. The valve bonnet M56 is shouldered on the inner rim of plate M63 and clamped thereto by a ring nut M67 screwed to a threaded portion of the valve bonnet M56 above plate M63. This arrangement, used for mounting each of the valves, provides that the bias assembly is aligned with the valve stem for each valve. If any of the assemblies are not aligned, it can be aligned by adding shims between the baseplate 30 and the respective mounting plate. The feature in FIG. 2 designated M69 is the upper portion of the packing assembly for the valve stem M57 and is also the same for each remaining valve.

Each of the mounting

posts

68a, 68b, 680 also have a sleeve inserted thereover, and the free ends of the posts are threaded to receive a spring guide cap 70 at a predetermined height above the baseplate 30. Three

locknuts

72a, 72b, 720 are threaded over the respective posts in order to fasten the spring guide cap 70 against the force of a bias spring 76 disposed between the stem plate M64 and a spring guide 74 in the interior of spring guide cap 70. The spring guide cap 70 has a centrally located aperture 73 through which the upper portion of the stem extension 60 moves in order to insure axial alignment of the stem extension 60.

In FIG. 3, the valve M in the left bank is stroked alternatively with the valve A in the right bank by the reciprocating action of a crank arm AM80 which has an involute spline at 55 engaged with the spline of the drive shaft 54. The crank arm AM80 is split for ease of assembly, and the splines are locked under clamping action by drawing the split halves together by means of a screw AM81. The crank arm AM80 extends perpendicular to the longitudinal axis of the drive shaft 54 and terminates in a pair of fork lifter surfaces M82 engaging stem plate M64 and a pair of fork lifter surfaces A82 engaging a stem plate A64 for valve A. An identical crank arm assembly to that of AM80 is provided to actuate valve pairs B, M and V, P. A crank arm C80 for valve C is shown in FIGS. 2 and 4, the fork lifter surfaces C82 being shown in FIG. 2 engaging the stem plate C64 for valve C. The opposite end of crank arm C80 extends to the region of the yoke 48 and terminates in a pair of drive forks C83 which will subsequently be described with reference to FIGS. 4 and 40. It should be recognized that the crank arm C80 is designed to sustain heavier loading forces than the other crank arms in the valve actuator assembly 32 since the crank arm C80 is used to stroke valve C as well as providing the motive force for the other valves in the valve actuator assembly by the rotation of drive shaft 54.

Referring again to FIG. 3, a position limit signal switch A84 is shown associated with the valve bias assembly A58 for valve A. A bracket A86 is used to mo unt the limit switch A84 to the baseplate 30. The limit switch A84 includes a switch body 88, wherein the switch contacts reside, and a switch lever 90 is pivoted thereto having a follower wheel 92 in contact with the stem plate A64 so that the stroke of valve stem A57 moves the switch lever 90 to actuate the switch contacts. A position limit switch assembly similar to that for valve A is also provided for valves B and P as shown in FIGS. 2 and 4. The interconnection and operation of the limit switches A84, B84, P84 with the system logic terminal within 36, the system control logic and the induction motor 40 will later be described with reference to FIG. 6.

Referring to FIG. 4 and to FIG. 4a, more clearly showing the driving assembly within the yoke 48, a ram screw 94 projects downwardly from the gear train within 36 into the yoke 48. The controller 34 is geared with a conventional Acme screw for driving the ram screw 94 upwardly and downwardly under power of either the handwheel 38 or the motor 40. The controller 34 may be of the type manufactured by the Link- Belt Company known as ELECTRODYNE, TN-2000 Series, Automatic Valve Operator. This type of controller provides a declutchable handwheel 38 and an internal torque limit switch for limiting the stroke of the ram screw 94 at a predetermined load. The controller 34 may also be one of several other types available and known to those skilled in the art.

The end of the ram screw 94 projecting into the yoke 48 is threaded into an actuator ram 96 and is secured thereto by a lock washer 99 and jam nut 98. The actuator ram 96 has a centrally located slot 100, as may be seen by referring to FIG. 4a. The lower end of the actuator ram 96 projects into a guide block 107 which has a centrally located aperture therethrough to allow the actuator ram 96 to vertically move therewithin. A mating fit of machined surfaces reduces friction and provides smooth action. The guide block 107 may be split into identical halves for ease of assembly, and in any event it is secured to the yoke 48 by means of a plurality of mounting screws 1080, 108b. A lubrication fitting 109 is provided in the guide block 107 in order to introduce a lubricant to reduce the friction within the guide block 107.

As described earlier, the crank arm C80 terminates within the yoke 48 in a pair of drive forks C83. The drive forks C83 have an aligned bore therethrough for accommodating a roller shaft 102 which passes through the horizontal slot 100 in the actuator ram 96. The purpose of the horizontal slot 100 in the actuator ram 96 is for providing the proper clearance to permit the actuator ram 96 to move in the vertical plane while the crank arm traces an arcuate path having a center on the axis of the drive shaft 54. A stop plate 103 is secured to the fork lifter C83 at one end of the roller shaft 102 in order to retain the roller shaft 102 therewithin, and a similar stop plate 104 is secured to the fork lifter C83 at the other end of the roller shaft 102. The combination of the stop plates 103, 104 and the fork lifter C82 mentioned above are also provided to retain a lubricant which may be replenished through a pair of

lubrication fittings

105, 106 in the stop plates 103, 104 respectively.

As may be seen in FIG. 4, a set of mechanical stops are provided in order to limit the actuator ram 96 at each end of its vertical stroke if the position limit signal switches or torque limit switch are exceeded. A stop screw 110, in alignment with the actuator ram 96, is threaded through the baseplate 30 and locked thereto by means of a lock washer 114 and a jam nut 112. The purpose for this mechanical stop is to prevent the ram screw 94 from moving downwardly through the aperture 111 in the yoke 48 more than a predetermined amount as determined by the position of the stop screw 110. At the upper end of the ram screw 44a, near the indicator 44, a conventional fixed stop 44b in the shape of a washer is used to prevent the actuator ram 96 from moving vertically upward more than a predetermined amount. It should be understood that the provision of stops is necessary in the hand mode of operation, by the handwheel 38, because the torque limit switch within the controller 34 is only operative in the automatic mode of operation, i.e. when the motor 40 is operative. It should also be clear that the indication given by the indicator 44, as is more clearly seen with reference to FIG. 3, is by way of the vertical position of a ram screw extension 44a in the indicator 44. Normally, the fixed stops are not reached in the hand mode of operation since the person turning the handwheel 38 will stop turning when the extension 44a reaches the appropriate vertical level corresponding to BURNER OFF, TRIP, BURNER ON for lowermost, intermediate and highest level indications respectively.

Referring now to FIG. 6, the interrelationships between the position limit signal switches A84, B84 and P84 are shown. These switches are connected to the system logic terminal within block 36 and the system control logic provides control of the motor 40 therethrough. These switches are mechanically actuated by the stem motion of valves A, B, P as schematically illustrated by the mechanical connection between the valve stems A57, B57, P57 and the related switch contacts. These switches are utilized as a means of signaling the system control logic so that it may cut off power to the motor 40 when the selected operating condition of the valves has been achieved. It should be recalled from FIG. 5 that valves A, B and their associated switches are in the first valve bank, and valve P and its associated switches are in the second valve bank, thus providing limit switches in each valve bank.

The state of the switches A84, B84, P84 in FIG. 6 are for the TRIP condition for the valves in the valve manifold assembly 10a. The TRIP condition as defined earlier means that valves A, B, M, N, P and V are fully closed and valve C is partially open, corresponding to the horizontal position of the crank arms designated by the numeral in FIGS. 2 and 3. The switch A84 includes switch contacts and switch contacts 122 which are both closed when valve A is closed, and switch B84 includes

switch contacts

124 and 126. The switch contacts 124 are closed when valve B is closed, and the switch contacts 126 are open when valve B is closed. The switch P84 is identical in operation to switch 884 since it includes switch contacts 128 which are closed when valve P is closed and switch contacts 130 which are open when valve P is closed. It should be understood from the foregoing that the switch contacts associated with each of the valves A, B, P reverse their respective states (i.e. closed to open, open to closed), when the respective valves open a predetermined amount.

The

switch contacts

120, 124 are wired in series, and a series connection for

switch contacts

122, 128 is also provided. The wiring scheme into the system logic terminal 36 will now be explored. As was described above, the condition shown for the switch contacts is for the TRIP condition corresponding to all valves being closed except the valve C which is partially open. This insures that steam will not purge oil into the furnace while explosive conditions exist. This condition may be more readily visualized by referring to FIG. 7 which is a graphical representation of the valve characteristics for the valve manifold assembly and shows the TRIP condition at an intermediate abscissa on the graph. The series connection between

switch contacts

122 and 128, when both the first and second banks of valves are closed, signals the system control logic that the TRIP condition is the state of the valves. If the burner is signalled into operation, valves A, B, V begin to open as illustrated by the valve characteristics above the intermediate abscissa in FIG. 7. This continues until the BURNER ON condition is reached where the valves A, B, V are maintained open while the burner is in operation. The switch contacts 126 in switch B84 are closed when valve B is open thus signalling the system control logic that the BURNER ON condition prevails.

If it is desired to shut the burner off, the first bank of valves A, B, V are stroked closed and the second bank of valves M, C, N, P are stroked in the open direction until the BURNER OFF condition is achieved as shown below the intennediate abscissa in FIG. 7. The valves M, C, N, P are maintained open. When valve P is open, the switch contacts 130 in switch P84 are closed, thus signalling that the valves in the second bank are opened so as to signal the system control logic that the purging or cooling steam is being supplied to burner. It should also be noted that when valves A, B are closed, the series connection between

switch contacts

120, 124 signals the system control logic that supply and return oil pressure has been shut off.

Considering that the valve manifold 10a is a safety shutoff device for a burner, the valves chosen to be used should insure positive shutofi of both the fuel oil and steam supplied to each burner. The valves chosen to be used should also have suitable characteristics to allow a smooth transition from one operat ing condition to another so that the operation of one burner or group of burners does not substantially affect other burners which may be in service and to provide a minimum pressure difierential across each valve when it is open. An additional consideration for the valves chosen to be used in the manifold is that they require minimum maintenance and provide maximum reliability since the number of valves used in a plural burner boiler system may become large.

Referring now to FIG. 4 in conjunction with the valve characteristics shown in FIG. 7, the oil supply valve A, shown in partial cross section, is of a single seat design with a spring to close arrangement provided by the valve bias assembly A58. The valve A is designed so that line pressure also tends to close the valve, thus providing for a maximum shutoff capability of the valve. Valve A includes a removable valve seat A142 and a valve plug A140 which is specially shaped so that the flow to the burner is very small when the valve begins to open. The plug and seat of valve B is like that of valve A so that the flow of fuel oil in the return line is very small when valve B begins to open. This feature is illustrated in the opening portion of the characteristic curves for valves A, B in FIG. 7, and it is essential in order to minimize oil header pressure fluctuations as a burner is shut down or lit. The valve plugs for valves A and B have a Teflon insert (A144 for valve A) which seals off flow when it contacts the bore of the seat A142. The metal portion of the plug A140 contacts the metal seat A142 after another one-fourth inch of stem travel. This value is typical and varies with the design of the valve. This overtrav'el feature provides a margin within which the limit switches A84, B84 can be properly set in order to insure that the respective valve is shut off when the switch signals that condition to the system control logic. The characteristic curve for valve B in FIG. 7 shows that it begins to open a short time interval after valve A begins to open. This delay is adjustable by means of locking the stem plate B64 at a position on the valve stem extension B60 so that the fork lifter surfaces B82 contact the stern plate B64 subsequent to the contacting of the stem plate A64 by its fork lifter surfaces A82. This initial delay of opening valve B insures that supply oil will begin to reach the burner nozzle before the return oil valve B begins to open. Both the valves A and B along with the remaining valves in the travel each have approximately percent of their flow area exposed. Referring to FIG. 2, valve N includes a plug N140, a seat N142 and a Teflon insert N144 which serves the same purpose as the Teflon insert provided in valves A and B. The quick opening characteristic of valve N, typical also of valves M, P, V, is attributed to the shorter length of the plug N140 as may be seen by comparing its length with that of plug A140 in FIG. 4. Valves M, P open concurrently with valve N as may be seen by referring to FIG. 7. The drain valve V begins to open and closes concurrently with valve B as shown.

The oil bypass valve C, shown in partial cross section in FIG. 2, includes a seat C142 and a plug C140 which has a linear characteristic. The C valve has a metalto-metal seat design so that fuel oil flow can be diverted through it before valves A and B reach shutoff. The valve C is furnished with a linear characteristic because the difference in supply and return oil pressures is approximately the same over the entire flow range of the burner. The C valve having the characteristic designated 1) in FIG. 7 may typically be used for burners having capacities up to l4,000 pounds per hour and the C valve having the characteristic (2) may be used for burners having a maximum capacity of 30,000 pounds per hour.

It should be noted that the C valve begins to open before the A and B valves are fully closed, and the C valve continues to open until at the TRIP condition it is approximately 50 percent open. The C valve continues to be stroked open as the bank of valves including valves C, M, N, and P are stroked open in the direction of the BURNER OFF condition. At the BURNER OFF condition the M, N, P valves are 50 percent open corresponding to 30 percent flow area exposed and the C valve is percent open corresponding to 100 percent flow area exposed. The 20 percent restriction of flow area in the M, N, P valves at the BURNER OFF condition is present for the reason that the C valve is concurrently stroked open with these valves, and the C valve must be open for both the TRIP and BURNER OFF condition. The partial opening of the C valve in the TRIP condition satisfies one of its functions which is that of keeping the fuel oil supply and return lines, HA1, HA3 in FIG. 1, warm and clear for both conditions.

The opening sequence of the C valve also assists in the function of minimizing oil header pressure fluctuations as a burner is shut .down or lit since it begins to open before valves A and B are fully closed and does not close until valves A and B are partially open in the opposite direction of operation. If it is found necessary to either increase or decrease the steam flow to the particular burner or group of burners for purging or cooling, the valves M, N, P can be adjusted by repositioning their respective stem plates to the proper position in order to change the openings of valves M, N, and P. In this way it is also possible to adjust the trip condition opening of the C valve.

Referring again to FIG. 7 and in particular to the time ordinate of the graph which is graduated in seconds, it should be noted that the total stroke speed of the valves in the manifold is 15.7 seconds from the BURNER ON to the BURNER OFF condition. This is a typical time interval when the induction motor 40 is supplied with 60 c.p.s. power. A 50 c.p.s. source of power to the motor would cause the total stroke speed to be approximately I9 seconds. Oil flow, however, is interrupted when stroking from the BURNER ON to BURNER TRIP or BURNER OFF conditions in approximately 8 seconds with 60 c.p.s. power and 9.5 seconds with 50 c.p.s. power supplied .to the motor. These values are typical but are not to be construed as limiting since modifications and alterations will occur to others upon the understanding of this specification.

.It is our intention to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalence thereof.

What we claim as new and desire to secure by Letters Patent of the United States is:

l. A valve actuator manifold for lighting off, maintaining fire on, and shutting down one or more burners in a return flow oil burner system, comprising:

a base having a central axis and a plurality of spaced apertures, some of the apertures forming aperture pairs, each pair having one aperture on either side of the central axis located on an axis perpendicular to the central axis;

a plurality of valves independently biased in the closed direction, said valves being mounted in said base and some of said valves forming a first valve bank on one side of the central axis and the other said valves forming a second valve bank on the other side of the central axis, each said valve having a valve stem which is adapted to actuate said valve through the aperture associated therewith in said base;

a drive shafi joumaled for rotation through a predetermined angle plus and minus of a reference position, said shaft being joumaled along an axis parallel to the central axis of said base;

a plurality of crank arms spaced along said drive shaft and locked thereto, each said crank arm projecting perpendicular from the journal axis of said drive shaft, each of said crank arms embracing at least one of said valve stems to actuate said valve upon rotating of said drive shaft;

means for interconnecting the inputs and outputs of said plurality of valves to oil and steam sources and returns for the burner; and,

means for controlling the angular position of said drive shaft to alternatively actuate said first and second valve banks to supply the burner in the oil burner system with oil and steam for lighting off, maintaining fire on and shutting down the burner.

2. The valve manifold of claim 1, wherein each said valve includes a spring to close bias assembly, said bias assembly comprising: a valve stem extension secured to the valve stem, said stem extension having exterior threads; a stem plate having interior threads threaded over said extension, said stem plate being lifted by said crank arm to open said valve; and, means for locking said stem plate to said extension at substantially any point on the threaded portion of said stem extension so that said valve is stroked open in a predetermined sequence with respect to the other said valves.

3. The valve manifold of claim 2, wherein said first valve bank includes an oil supply valve and an oil return valve to communicate oil to and from said burner when said first valve bank is actuated, said oil supply valve and oil return valve including first means for signalling said control means when both of said valves reach a predetermined position.

4. The valve manifold of claim 3, wherein said second valve bank includes a steam supply valve, a pair of steam valves to communicate variable pressure steam from said steam supply valve to said burner when said second valve bank is actuated, and an oil bypass valve to shunt oil passed said first valve bank when said second valve bank is actuated, said oil bypass valve also being adapted to shunt oil passed said first valve bank when all of the remaining valves of said plurality are closed, said steam supply valve including second means for signalling said control means when both said steam supply valve and said oil supply valve reach a predetermined position.

5. The valve manifold of claim 4, wherein said first valve bank also includes a drain valve to drain any oil leakage from said pair of steam valves and from said interconnecting means between said pair of steam valves and said steam supply valve when said first valve bank is actuated, said drain valve also serving to drain any condensed steam when said first valve bank is actuated.

6. The valve manifold of claim 4, wherein said oil bypass valve is a linear operating valve providing full flow capacity when said second valve bank is actuated and providing zero flow capacity when said first valve bank is partially actuated.

7. The valve manifold of claim 4, wherein said control means includes an electrically driven motor, alternatively activated by said first and second signalling means, mechanically coupled to said drive shaft for alternatively actuating said first and second valve banks.

The valve manifold of claim 7, wherein said control means also includes means for interrupting the power to said motor upon excessive angular deviation of said drive shaft from the predetermined angular limits.

9. The valve manifold of claim 3, wherein said oil supply valve and oil return valve each include a slow opening valve plug as compared with relatively fast opening valve plugs for said pair of steam valves, said steam supply valve and said oil drain valve, so as to minimize oil pressure fluctuations in the retum flow oil burner system when lighting off and shutting down the burner.

10. The valve manifold of claim 9, wherein said crank arm associated with said oil supply valve opens said oil supply valve in advance of opening said oil return valve and said drain valve by said associated crank arms and more in advance to fully closing said oil bypass valve by said associated crank arm in order to provide a smooth transition between supply and return oil to said burner when lighting off the burner.

11. The valve manifold of claim 9, wherein all of said valves in said first valve bank, said pair of steam valves and said steam supply valve in said second valve bank each include a Teflon insert on said respective valve plugs adapted to contact the bore of the valve seat to effect shutoff of said respective valves in advance of shutoff by the seating of the respective valve plugs.

Claims

1. A valve actuator manifold for lighting off, maintaining fire on, and shutting down one or more burners in a return flow oil burner system, comprising: a base having a central axis and a plurality of spaced apertures, some of the apertures forming aperture pairs, each pair having one aperture on either side of the central axis located on an axis perpendicular to the central axis; a plurality of valves independently biased in the closed direction, said valves being mounted in said base and some of said valves forming a first valve bank on one side of the central axis and the other said valves forming a second valve bank on the other side of the central axis, each said valve having a valve stem which is adapted to actuate said valve through the aperture associated therewith in said base; a drive shaft journaled for rotation through a predetermined angle plus and minus of a reference position, said shaft being journaled along an axis parallel to the central axis of said base; a plurality of crank arms spaced along said drive shaft and locked thereto, each said crank arm projecting perpendicular from the journal axis of said drive shaft, each of said crank arms embracing at least one of said valve stems to actuate said valve upon rotating of said drive shaft; means for interconnecting the inputs and outputs of said plurality of valves to oil and steam sources and returns for the burner; and, means for controlling the angular position of said drive shaft to alternatively actuate said first and second valve banks to supply the burner in the oil burner system with oil and steam for lighting off, maintaining fire on and shutting down the burner.

8. The valve manifold of claim 7, wherein said control means also includes means for interrupting the power to said motor upon excessive angular deviation of said drive shaft from the predetermined angular limits.

9. The valve manifold of claim 3, wherein said oil supply valve and oil return valve each include a slow opening valve plug as compared with relatively fast opening valve plugs for said pair of steam valves, said steam supply valve and said oil drain valve, so as to minimize oil pressure fluctuations in the return flow oil burner system when lighting off and shutting down the burner.