US3212555A

US3212555A - Automatic gun integrity checking system

Info

Publication number: US3212555A
Application number: US421283A
Authority: US
Inventors: Jack A Schuss; Virginius Z Caracristi
Original assignee: Combustion Engineering Inc
Current assignee: Combustion Engineering Inc
Priority date: 1964-12-28
Filing date: 1964-12-28
Publication date: 1965-10-19
Anticipated expiration: 1982-10-19

Description

Oct. 19, 1965 J. A. scHuss ETAL 3212555 AUTOMATIC GUN INTEGRITY CHECKING SYSTEM Filed Dec. 28, 1964 2 Shee's-Sheet 1 OIL BURNER ATTORNEY Oct. 19, 1965 J. A. scHuss E'rAL 3,2l2,555

AUTOMATIC GUN INTEGRITY CHECKING SYSTEM 2 Sheets-Sheet 2 Filed Dec. 28, 1964 INVENTOR. JACK A. SCHUSS YV!RG|NIUS Z. CARCRISTI ATTORNEY United States Patent O 3,212,555 AUTMATHC GUN INTEGRHTY CHECIKHNG SYSTEM .llaclr A. Schuss, Hartford, and Virginins Z. Caracristi,

West Hartford, Conn., assignors to Combustion Engineering, Inc., Windsor, Conn., a corporation of Delaware Filed Dec. 28, 1964, Ser. No. 421,283 4- Claims. (Cl. 158-363) This application is a continuation-in-part of application Serial No. 240,872, filed November 29, 1962, now abandoned. This invention relates to an oil burning system, and in particular to such a system utilizing wide range burners.

One method of allowing increased turn down ratio (or a wide range of firing capacity) for oil burners using mechanical oil atomization means, is to utilize an oil supply line fceding oil to the burner, along With an oil return line, that under some Operating conditions allows a portion of the oil to return to the source of supply. When it is desired to decrease the fuel burning capacity of the oil burner, a valve positioned in the oil return line is gradually opened, thereby decreasing the oil pressure in the burner chamber, and consequently decreasing the amount of fuel that is actually burned. Recently, in large installations which require a multiplicity of oil burners, for example the furnace of a steam generating unit, endeavors are being made to more fully automate and smplify the controls or regulation of the entire burner system, so that less personnel is needed. This will eliminate to some eXtent the possibility of improper operation caused by human error. This invention is directed to control apparatus for oil burner systems using oil supply and oil return lines for each individual burner of the system.

In an automated plant with a multitude of devices and control loops .and with less time 'on the part of the operator, if any, to pay attention to the individual control loops, it is increasingly necessary that the control system itself monitor and supervise its own devices and take corrective action in case of malfunction.

It is an object of this invention to provide an automatic control for each individual burner of a burner system which will stop the flow of fuel to an individual burner in the event that one of the fuel lines leading to or from the burner ruptures, or the burner tip becomes badly worn.

It is a further object of this invention to provide a prechecking device for each burner of the system which will sense a break in the fuel line leading to or from an individual burner, or will sense a badly worn burner tip, and if such condition is sensed, .the prechecking device will thereafter prevent the opening of a valve in the fuel supply line for that particular burner.

'Other objects and advantages of our invention will be more readily understood by reference to the accompanying drawings in which:

FIGURE l is a diagrammatic illustration of a burner system incorporating our invention;

FIGURE 2 is an enlarged view of the control arrangement for a single one of the burners of the system of FIGURE 1; and

.FIGURE 3 is a cross sectional view showing the construction of a burner tip.

Referring to FIGURE 1,

numerals

10, 12 and 14 designate three oil burners of an oil burner system. Although only three burners have been illustrated, any number of burners could be .tied into the common system. For example, the burner system could be utilized at a steam generating site where the burners would supply 3,212,555 Patented ct. 19, 1965 ICC fuel to the boiler furnace, the heat generated by the burning of such fuel being utilized to generate steam. In such a system, it would not be uncommon to utilize as many as twelve or twenty-four individual oil burners in the burner system.

As illustrated, oil is supplied to each of the burners by means 'of -

oil supply lines

24, 26 and 28 all of which eX- tend from a common oil supply manifold 16. Constant delivery pump 18 Supplies oil to the manifold 16 at a constant pressure, for example 1000 p.s.i. Extending lfrom each of the

oil burners

10, 12 and 14 ar-e

oil return lines

30, 32 and 34 all of which are connected to a common oil return manifold 20. This returned oil flows into an oil sump or storage tank 22 which is connected to the upstream side of constant delivery pump 18. A valve 36 is positioned in oil return manifold 20 downstream of all of the individual oil return lines, and this valve can be opened or closed to |thus vary the oil pressure in each of the oil burners. Control 38 is indicated for varying the position of valve 36. This control 38 can receive a signal from any central control point where the amount of fuel to be fired in the burners is determined.

FIGURE 3 illustrates the details of the burner .tip of burner 10. As shown, central oil supply passage 82, which is connected to oil supply line 24, feeds oil through restricted openings 88 into chamber 84. These openings 88 introduce oil tangentially into chamber 84. Also connected to chamber 84 by means of restricted opening is annular oil return passage 80 which is connected to oil return line 30. The nozzle has a restricted opening 86 by means of which atomized oil is sprayed into a furnace interior where combustion occurs.

The details of an individual burner and its associated elements will now be explained. Since each burner of the entire burner system is dentical in construction and operation, only one of such burners 10 and its associated elements as indicated by numeral in FIGURE 1 will be described. Looking to FIGURE 2, positioned within supply line 24 is valve 40, the actuator of which is indicated at 42. Forming a portion of the supply line 24 is flexible hose 44. Flexible hose 46 forms a portion of the return line 30'. These two fiexible hoses are necessary in order to enable the oil burner 10 to be extended into and retracted from a furnace interior.

As shown, oil burner 10 may be moved either in a forward or backward direction by means of the pistoncylinder arrangement 48. Four-way valve unit 50 controls the admission and venting of air to the opposite sides of piston 48.

Suitable actuators

56 and 58 allow the connection of air supply line 52 or vent line 54 to either the left-hand or right-hand side of piston 48 as desired.

A check valve 60 is positioned within return line 30, which allows flow only in the direction from the oil burner 10 to the oil return manifold 20. Numeral 62 designates a pressure differential measuring device. This device consists of a fiexible diaphragm 64 having a stem t connected thereto which contains an electrical contact member thereon. The contact member contained on stem 66 is positioned so as to come into contact with contacts 68 when certain conditions exist, as more fully described hereafter. The pressure measuring device 62 contains pressure taps '72 and 74 connected to the upstream and downstream sides of check valve 60, respectvely.

Pressure measuring device 62 is continuously monitoring the oil burner while it is in operation. lf one of the hoses 454 or 46 ruptures or the burner tip becomes badly worn, .the device 62 causes the closure of oil supply valve 40, thus putting the oil burner out of operation.

Normally closed valve 40 is opened by energization of actuator 42. This energization takes place by closing switch 132 at the central control station, thus completing a Circuit to actuator 42 through conductors 168, 170, and normally closed

switches

146 and 135. Closure of switch 132 also puts into operation device 62, by energizing Conductors 1'76 and 178, which contains contacts 68 therein. The switch arm of device 62 coacts with the contacts 60.

During normal operation of the burner, three-way valve 112, which is in the oil return line 30, is in a position allowing flow from one portion of return line 30 to the other portion thereof. When the oil burners of the system are to be operated at their highest firing capacity, control 38 (shown in FIGURE 1) will receive a signal from the central control point which will move variable valve 36 to its fully closed position. Under these Conditions, the highest pressure possible exists in the burner tip chambers, such as Chamber 84 illustrated in FIGURE 3. Thus the oil in Chamber 84 is forced through nozzle opening 86 into the furnace interior at its highest rate. When it is desi-red t-o reduce the firing capacity of the burners, control 38 will move valve 36 to a position other than its fully closed position, thus allowing some of the oil to return to storage tank 22. This reduces the pressure in the burner chambers, thus reducing the firing rate of each individual burner.

When the

fiexible hoses

44 and 46 of the oil burner are in good condition and contain no leaks or breaks, and when the burner tip is properly attached and not badly worn, the pressure differential measuring device 62 will maintain Contacts 68 open. When the valve 36 in oil return manifold (shown in FIGURE l) is completely closed, there will be no flow through oil return line 30, nor in any of the other return lines. Thus the pressure differential across check valve 60 will be zero. When valve 36 is in an open position, there will be some flow through oil return line 30, and thus pressure ditferential measuring device 62 will sense a higher pressure in pressure tap 72 than it will in pressure tap 74, due to the slight restriction formed by check valve 60.

If one of the

fiexible hoses

44 or 46 ruptures or springs a leak, or if the burner tip becomes badly worn so that oil is not issuing therefrom in a fine atomized spray but is gushing therethrough, pressure diiferential measuring device 62 will cause closure of contacts 68, so as to energize relay 138, thus opening switch 146. Because there are a number of oil return lines that feed into the common oil return manifold 20 (FIGURE 1), a back pressure always exists in the manifold 20, and also in each of the

oil return lines

30, 32 and 34 downstream of the check valves placed therein. If one of the hoses breaks, or the burner tip becomes badly worn, all of the oil will be flowing through such break or badly worn tip, and the pressure on the upstream side of the Check valve Will be greatly reduced. The back pressure existing in oil return manifold 20 will under these conditions tend to cause the oil to flow in a reverse direction against check valve 60, of the particular oil burner where the hose break or badly worn burner tip exists. Thus the pressure in pressure tap 74 will exceed the pressure in pressure tap 72, moving the diaphragm 64, along with its connected stem 66, to the right. The contact member on stem 66 then will engage contacts 68, Completing the Circuit to relay 130, thus opening switch 146 under these conditions. This breaks the Circuit to actuator 42, causing immediate closure of valve 40.

Thus if the pressure measuring device 62 measures a zero pressure diiferential or a diiferential with the highest pressure on the upstream side of the check valve, the burner is in good condition, and is allowed to Continue to operate. If the pressure measuring device senses a higher pressure on the downstream side of the check valve than on the upstream side thereof, the valve in the supply line of that particular burner is closed. The remaining burners in the system will Continue to operate, and the only burner that will be removed from operation is the one containing the ruptured hose or badly worn burner 4 tip. Thus it can be seen that the burners are continuously monitored during their normal operation.

Also contained in the oil return line 30 is three-way valve 112. One of the purposes of this valve is to permit a prechecking yor pretesting of the flexible hoses and the burner tip prior to the time when oil is actually supplied thereto, to determine whether or not such members are in good condition. The pretesting medium is fiuid other than the fuel oil. Advantage is taken of the availability of air or steam for post-shutdown gun scavenging so that it can also be utilized as the gun pretesting medium. As illustrated in FIGURE 2, threeway valve 100 is connected to a suitable source of fiuid under substantially Constant pressure by supply line 104. This fluid may for example be either steam or air. Numeral 102 denotes a suitable actuator for valve 100, which is energized by closure of switch 130, by way of conductors 164 and 166. When actuator 102 is energized, it rotates valve 100 clockwise, thus connecting line 104 to line 113. When actuator 102 is not energized, line 113 is in communication with vent 106 through valve 100, as illustrated in FIGURE 2.

The line 113 downstream of valve contains check valve and a restriction 116, for example an orifice. This line 113 branches ofi? into line 108 which is Connected to the oil supply line 24 downstream of valve 40, and also line 110 which is connected to oil return line 30 through three-way valve 112. When actuator 114 is deenergized, valve 112 is in the position shown in FIGURE 2, allowing flow from line 110 into the right-hand portion of return line 30. Numeral 118 indicates a flow measuring device, which consists of a flexible diaphragm 119 having a stem 120 connected thereto, and pressure taps 126 and 128 positioned on the downstream and upstream sides of 116, respectively. Stem 120 contains a contact member which Coacts with contacts 122. When these two members are engaged, a Circuit is completed through switch 130, and

conductors

160, 162, energizing relay 136, thus opening normally closed switch 135. The pin 142, which is biased by spring 144, engages slot 140 when switch moves to its open position, thus locking it in that position. Thus once switch 135 is opened, it is locked in that position until reset by the operator.

The flow measuring device 118 works in the following manner. Upon closure of switch 130, valve 100 is actuated to its position connecting line 113 to the supply line 104. Valve 112 is in the position shown in FIGURE 2, allowing flow from line 110 to line 30; and valve 40 is in its closed position. If there are no breaks in the

hoses

44 and 46, and if the burner tip is not badly worn, a predetermined pressure dilferential will be established across orifice 116. If there is a break in one of these lines, or if the burner tip is badly worn, the flow through line 113 will be greatly increased, resulting in an increased pressure difierential across the orifice 116. When this pressure dilferential exceeds a predetermined maximum, indicating an unusually high rate of flow, contacts 122 will be engaged by the contact member carried by stem 120. This condition results in opening switch 135, and locking it in such open position by means of the pin and

slot arrangement

140, 142, as earlier deson'bed.

When switch 135 is locked in its open position, it will not be possible for normally closed valve 40 to be actuated to its open position by actuator 42. Valve 40 is opened in the normal Chain of events by closure of a switch 132 (from the central control point). Actuator 42 is energized through conductors 168 and 170, and normally closed

switches

146 and 135. Thus before valve 40 could be opened, it would be necessary for the operator to repair the broken hose or replace the worn burner tip, and remove the interlock by resetting switch 135 in its closed position.

The prechecking system that has been shown can also be used as the purging system for the burner. In other words, when the burner system is shut ofr by closing the valve 49 in the oil supply line, some oil will be trapped in the lines adjacent to the burner. By forcing steam or air through the purging system, this oil can be forced out of both the oil supply line and the oid return line, and also out of the burner tip, into the furnace interior.

The operation of the entire apparatus shown in FIG- URE 2 will now be described. The first step in starting up the burner unit is to move the burner into the furnace interior. Next, switch 130 is closed from the central control station. This energizes valve 100 by way of conductors 164 and 166, thus opening this valve, allowing steam or air to flow into line 113 for prechecking the burner. Valve 112 in return line 30 is in the position illustrated in FIGURE 2. If there is a ruptured hose or unduly worn burner tip, the flow through line 113 will be greatly increased, resulting in an increased pressure differential across orifice 116. This causes closure of contacts 122, thus completing a circuit through switch 130 and

Conductors

160, 162, to relay 136, thus opening switch 135. The switch is latched in its open position by pin and slot arrangement 141), 14-2, thus preventing valve 46 in the oil supply line 24 from thereafter being opened, by closure of switch 132.

After a predetermined period of time, the operator would open switch 131), and close switch 132, which is also located at the central control station. Opening of switch 130 de-energizes valve 106, allowing it to move to its vent position. Opening of switch 130 would also deenergize the Circuit to relay 136 of switch 135, but because of the latch arrangement, switch 135 would remain in the open position. If this happens, as mentioned above, it will not be possible to thereafter open valve 40.

If the burner was in proper working order during the pretesting operation, then switch 135 will have remained in its closed position. Thus when switch 132 is closed, a circuit will be completed through conductors 168, 170, and switches 146, 135 to energize actuator 42, thus opening valve 40. A circuit is also completed through

conductors

172, 174, energizing actuator 114. Energization of 114 rotates three-way valve 112 90 Clockwise, thereby putting the two portions of return line 30 in communication with each other. The burner is thus in operation, and the rate of firing of the burner can be controlled from the central control station by varying the position of valve 36 in the oil return manifold 20 (FIGURE 1).

Closure of switch 132 also puts the continuous monitoring or testing device 62 into operation. If at any time during the operation of the burner one of the hoses ruptures, or the burner tip becomes badly worn, the pressure differential measured by device 62 will be reversed (a higher pressure exists in pressure tap 74 than exists in pressure tap 72). This will Close contacts 68, thus completing a circuit through switch 132, conductors 176, 178 to relay 138. Switch 146 will be opened, and held in the open position by pin and slot arrangement 148, 151i). Opening of switch 146 breaks the circuit to actuator 42, and valve 40 immediately closes.

When switch 132 is initially closed, the pressure measuring device 62 will be registering a zero pressure dilferential, or a reverse pressure differential, since there will be no fuel oil flowing through the return line 30 for a few seconds. ContaCts 68 thus might be closed at this time. In order to prevent the opening of switch 146 for these few seconds, until an oil flow is established through the burner, a timer switch 134 is provided in series with contaCts 68. This timer swtich is normally open, but closes after a predetermined time delay. Thus, for example, the timer switch is set to close after a predetermined time, of or seconds, from the time at which switch 132 is closed. This prevents relay 138 from being energized and switch 146 from opening until oil is flowing through the burner, and pressure measuring device 62 is properly Operating.

Although the flow measuring device that has been illustrated in the prechecking or testing system is a pressure differential measurng device located in line 113, other types of flow measuring devices could be used. For example, a restriction could be placed in line 108 or in line 110, and the pressure differential measured thereacross. A predetermined increase or decrease in the thus measured pressure differential could be used to indicate a break in one of the fiexible hoses.

While we have illustrated a preferred embodiment of our invention, many modifications may be made without departing from the spirit of the invention, and we do not wish to be limited to the precise details of construction set forth, but desire to avail ourselves of all changes within the scope of the appended claims.

What we claim is:

1. A fuel burning system comprising a fuel pump, a first manifold connected to the downstream side of the pump, a second manifold connected to the upstream side of the pump, a plurality of burners each of which receives fuel from the pump, each burner having a tip formed with a chamber, a plurality of first pipes connecting the first manifold to the chambers, a valve in each of said first pipes, a plurality of second pipes connecting the chambers with the second manifold, variable means positioned in the second manifold for varying the pressure in each of the chambers, flow measuring means positioned within each of the second pipes, each fiow measuring means being operatively connected to the valve in the first pipe of its respective burner in such a manner as to move the valve to its closed position when the condition of the fuel is such that it tends to flow from the second manifold to the chamber.

2. A fuel burning system comprising a fuel pump, a first manifold connected to the downstream side of the pump, a second manifold connected to the upstream side of the pump, a plurality of burners each of which receives fuel from the pump, each burner having a tip formed with a Chamber, a plurality of first pipes connecting the first manifold to the chambers, a valve in each of said first pipes, a plurality of second pipes connecting the chambers with the second manifold, a check valve in each of the second pipes which permit fiow of fuel only in the direction from the chambers to the second manifold, variable means positioned in the second manifold for varying the pressure in each of the chambers, pressure measuring means for comparing the pressure on opposite sides of each check valve, a plurality of control means, each Control means being operatively connected to the pressure measuring means and the valve of its respective burner in such a manner as to move the valve to its closed position when the pressure in the second line on the downstream side of the check valve exceeds the pressure on the upstream side thereof.

3. A fuel burning system comprising a fuel pump, a burner which receives fuel from the pump, the burner having a tip formed with a Chamber, a first pipe connecting the downstream side of the pump to the Chamber, a second pipe connecting the Chamber to the upstream side of the pump, a first valve in said first pipe, a second valve in said second pipe, a purge and prechecking system comprising a third pipe connected at an end to a source of purging fiuid, fourth and fifth pipes, the other end of the third pipe connected to the inlet ends of both the fourth and fifth pipes, the outlet end of the fourth pipe connected to the first pipe downstream of the first valve, the outlet end of the fifth pipe connected to the second pipe upstream of the second valve, flow measuring means positioned within the purge and prechecking system and interconnected with the first valve in such a manner that if the flow through the purge and prechecking system exceeds a given predetermined amount the first valve is thereafter prevented from opening.

4. A fuel burning system comprising a fuel pump, a first manifold connected to the downstream side of the pump, a second manifold connected to the upstream side of the pump, a plurality of burners each of which receives fuel from the pump, each burner having a tip forrned With a Chamber, a plurality of first pipes connecting the first manifold to the chambers, a first valve in each of said first pipes, a plurality of second pipes connecting the chambers With the second manifold, a check valve in each of the second pipes which permit fiow of fuel only in the direction from the chambers to the second manifold, variable means positioned in the second manifold for varying the pressure in each of the chambers, pressure measuring means for comparing the pressure on opposite sides of each check valve, a plurality of control means, each control means being operatively connected to the pressure measuring means and the first valve of its respective burner in such a manner as to move the first valve to its closed position when the pressure of the fuel in the second line on the downstream side of the check valve exceeds the pressure on the upstream side thereof, a purge and prechecking system for each of the burners, each purge and prechecking system comprising a third pipe connected at one end to a source of purging fluid, fourth and fifth pipes, the other end of the third pipe connected to the inlet ends of both the fourth and fifth pipes, the outlet end of the fourth pipe connected to its respective first pipe downstream of the first valve, the outlet end of the fifth pipe connected to its respective second pipe upstream of the check valve, fiow measuring means positioned Within the purge and prechecking system and interconnected With its respective first valve in such a manner that if the fiow through the purge and prechecking system exceeds a given predetermined amount the first valve is thereafter prevented from opening.

References Cited by the Examiner UNITED STATES PATENTS 1,745,331 1/30 Parker 158- 360 JAMES W. WESTHAVER, Primary Examner.

Claims

1. A FUEL BURNING SYSTEM COMPRISING A FUEL PUMP, A FIRST MANIFOLD CONNECTED TO THE DOWNSTREAM SIDE OF THE PUMP, A SECOND MANIFOLD CONNECTED TO THE UPSTREAM SIDE OF THE PUMP, A PLURALITY OF BURNERS EACH OF WHICH RECEIVES FUEL FROM THE PUMP, EACH BURNER HAVING A TIP FORMED WITH A CHAMBER, A PLURALITY OF FIRST PIPES CONNECTING THE FIRST MANIFOLD TO THE CHAMBERS, A VALVE IN EACH OF SAID FIRST PIPES, A PLURALITY OF SECOND PIPES CONNECTING THE CHAMBERS WITH THE SECOND MANIFOLD, VARIABLE MEANS POSITIONED IN THE SECOND MANIFOLD FOR VARYING THE PRESSURE IN EACH OF THE CHAMBERS, FLOW MEASURING MEANS POSITIONED WITHIN EACH OF THE SECOND PIPES, EACH FLOW MEASURING MEANS BEING OPERATIVELY CONNECTED TO THE VALVE IN THE FIRST PIPE OF ITS RESPECTIVE BURNER IN SUCH A MANNER AS TO MOVE THE VALVE TO ITS CLOSED POSITION WHEN THE CONDITION OF THE FUEL IS SUCH THAT IT TENDS TO FLOW FROM THE SECOND MANIFOLD TO THE CHAMBER.