US3491794A - Valve with force apparatus to oppose an applied suction force - Google Patents

Description

Jan. 27, 1970 E. v. GARNER 3,491,794

VALVE WITH FORCE APPARATUS To OPPOSE AN APPLIED SUCTION FORCE Filed Feb. 9, 1968 2 Sheets-Sheet 1 :3 r. H 1/55! E /A 6 E. v. GARNER 3,491,794

VALVE WITH FORCE APPARATUS TO OPPOSE AN APPLIED SUCTION FORCE Jan. 27, 1970 2 Sheets-Sheet 2 Filed Feb. 9, 1968 lIO VAC.

FIG 5 FEG 6 IN Hg United States Patent 3,491,794 VALVE WITH FORCE APPARATUS T0 OPPOSE AN APPLIED SUCTION FORCE Edward Vernon Garner, East Walpole, Mass., assignor to Bird Machine Company, South Walpole, Mass., a corporation of Massachusetts Filed Feb. 9, 1968, Ser. No. 704,467 Int. Cl. F16k 39/02 US. Cl. 137-565 11 Claims ABSTRACT OF THE DISCLOSURE A valve including apparatus for relieving pressure induced by vacuum between relatively movable parts of the valve and comprising force applying apparatus for applying a force opposite to that applied by the vacuum to one of said parts and actuating apparatus for the force applying apparatus responsive to the amount of the vacuum.

This invention relates to valves.

It is a principal object of the present invention to reduce the power required to drive, and to eliminate the valve chatter in, large vacuum-loaded valves. Other objects include decreasing the wear rate in such valves and providing for quick and easy separation of their major components for cleaning.

The invention accomplishes these and other objects by providing in a valve including two members having ports therein aranged to communicate with each other along an interface and suction apparatus for applying suction to at least one port, force applying apparatus for applying force in a direction tending to separate the members and an actuating system for actuating and controlling the force applying apparatus in acordance with changes in the suction level. In preferred embodiments the actuating system actuates the force applying apparatus only when the suction exceeds a predetermined level and the force applying apparatus is a fluid presure applying system which is manually actuable for separating the two members when no suction is being applied thereto.

Other objects, features and advantages will appear from the following detailed description of a preferred embodiment of the invention, taken in conjunction with the attached drawings in which:

FIG. 1 is a plan, partially schematic view of a valve and pressure relief system acording to the invention;

FIG. 2 is a schematic view of hydraulic force applying apparatus used in the system of FIG. 1;

FIG. 3 is a circuit diagram of an electric control system for the apparatus of FIG. 2;

FIG. 4 is a schematic view of an alternative force ap plying apparatus for use with the system of FIG. 1;

FIG. 5 is a graphical representation of the operation of the system of FIGS. 1-3; and

FIG. 6 is a graphical representation of the operation of a system including the apparatus of FIG. 4.

Referring more particularly to the drawings, there is shown in FIGURE 1 a valve in the form. of a fluid distributor, generally designated 10, of the type disclosed in Roos US. Patent No. 2,997,068. As illustrated, distributor 10 comprises a manifold 12 mounted on a stationary head 14 for rotation about its central axis 16 relative to head 14. Head 14 is secured to the upper end of a pedestal 18. Manifold 12 and head 14- each include a plurality of ports, 20 and 22 respectively, arranged in annular array about axis 16. Manifold 12 also includes a sealing ring 24 made of suitable bearing material, provided with ports 26 corresponding with ports 20 and secured on the bottom of manifold 12 to form a flat bearing face perpendicular to the axis of rotation and in rotary sliding sealing en- Patented Jan. 27, 1970 gagement with the upper face of head 14. Each port 26 of ring 24 of manifold 12 is brought into communication with each opposing port 22 of head 14 during rotation of manifold 12. Hoses 28 extend from each port 20 of manifold 12 to a filter cell (not shown). A conduit 30 is connected to each port 22 of head 14. Typically, one of conduits 30 is conected to a source of air or steam under pressure (not shown). The remaining conduits 30 are connected, as schematically illustrated in FIG. 1, to the inlet 33 of a vacum pump 31. Pump 31 continuously applies suction to most of conduits 30, this suction being applied to the filter cells conected to hoses 28 Whenever the respective ports 20, 26 are in communication.

Manifold 12 is located relative to head 14 by a cylindrical vertical spindle 32 centered by suitable bearings 34 within a centarl cylindrical bearing housing portion 36 of head 14. The upper end 38 of spindle 32 is fastened to manifold 12; the lower end 40 engages a thrust bearing 42. Housing portion 36, spindle 32 and thrust bearing 42 are all coaxial with axis 16.

Mounted within pedestal 18 coaxially with spindle 32 are a cylindrical cylinder mount 44 secured at its upper end to head 14, and a hydraulic cylinder 46 secured to the generally closed base of mount 44. The piston 50 of hydraulic cylinder 46, extends upwardly through a hole in the base of mount 44. A cylindrical tip member 52 connects the upper end of piston 50 and the bottom of a bearing support 48 in which thrust bearing 42 is seated. As shown, bearing support 48 is keyed to mount 44 by key 49 to prevent rotation and moves vertically within mount 44. A compression spring 54 surrounds tip member 52 to keep constant preload on thrust bearing 42. The upper end of spring 54 bears against bearing support 48 and its lower end against the base of mount 44. At the lower end of hydraulic cylinder 46 is provided apparatus including a stop adjust nut 56, a safety stop 58, a microswitch 60 and a switch actuating member 62 for limiting the vertical travel of piston 50. Hydraulic tubing extends from the inlet 64 and outlet 66 of hydraulic cylinder 46 through the wall of pedestal 18 to a hydraulic pump 68 mounted outside pedestal 18. A hatch 70 is provided in the side of pedestal 18 to permit access to the components therein.

The hydraulic system 71 and electric system for controlling cylinder 68 are shown in FIGS. 2 and 3. Referring to FIGURE 2, a first high-pressure hydraulic line 67 extends from the outlet of pump 68 to the inlet 54 of cylinder 46, and a second low pressure or return hydraulic line 69 extends from the outlet 66 of cylinder 46 to the pump sump 72. A pressure switch 74 and pressure gauge 76 are attached to high pressure line 67 adjacent the outlet of pump 68. A bleeder line 82, in which are provided a needle valve 78 and solenoid operated hydraulic valve 80 extends between high pressure line 67 and to the portion of return line 69 between pump 68 and sump 72.

FIGURE 3 illustrates the electrical control system in its normal operating configuration. As shown, the electrical system comprises a pair of taps 84 adapted for connection to a suitable source such as 110 volt A.C., and an upper branch 86 and lower branch 88 extending from taps 84 to the motor of pump 68. An indicator light 90 is connected in parallel with the pump. Three switches, microswitch 60, a vacuum switch 92 connected to the inlet 33 of vacuum pump 31, and pressure switch 74 are provided in series in upper branch 86. A by-pass line 94 including a manual operation switch 96 is connected in parallel with the portion of upper branch ineluding switches 60 and 92. A solenoid 81 controlling hydraulic valve 80 is connected in parallel with portion of the circuit including pump 68, light 90 and pressure switch 74 so that it will be actuated through branch line 86 when vacuum switch 92 and microswitch 60 are closed, or through by-pass line 94 when manual operation switch 96 is closed.

The illustrated system is automatically operable to reduce the force with which the sealing ring 24 of manifold 12 bears against head 14, thereby largely or entirely avoiding valve chatter and greatly reducing wear, and is manually operable to lift manifold 12 oif stationary head 14 for valve cleaning and maintenance. For automatic operation, the hydraulic and electrical systems of FIGURES 2 and 3 are set to actuate hydraulic cylinder 46, thereby causing its piston 50 to exert an upward vertical force against spindle 32 and manifold 12, whenever the vacum level at the inlet of vacuum pump 31 is greater than a predetermined level, typically 10 in. of mercury, below which valve chatter does not normally occur or is relatively insignificant. Microswitch 60 is normally held in a closed position by switch actuator 62. Pressure switch 74 is normally closed and automatically opens when the pressure at the outlet of pump 68 reaches or exceeds the present desired operating pressure of the hydraulic system. This operating pressure is determined with reference to the size of cylinder 46 and weight of manifold 12, and the opening point of switch 74 adjusted so that the force applied by piston 50 will be slightly less than the dead weight of the manifold plus a predetermined vacuum load. With reference to FIG. 3, it will be seen that power will be applied to pump 68 through branch line 86, actuating the pump, when vacuum switch 92 is closed. Vacuum switch 92 senses and is responsive to the vacuum level at the inlet of pump 31, and automatically closes whenever this sensed level is greater than the predetermined level. As shown, closing switch 92 also actuates solenoid 81 controlling hydraulic valve 80, closing valve 80.

In operation, pump 68 operates from the time switch 92 is closed until the pressure in the hydraulic system reaches the preset point at which pressure switch 74 automatically opens. As switch 74 is opened, current continues to flow through solenoid 81 so that thereafter valve 80 is held in its closed position and maintains a substantially constant high pressure in line 67, and correspondingly constant upward force by piston 50 even though the pump is not operating. Piston 50 continues to exert this force as long as the vacuum at the inlet of vacuum pump 31 stays above the predetermined level, e.g. 10" Hg. If the vacuum level drops below this level, switch 92 automatically opens, stopping current flow through solenoid 81 (and through the motor of pump 68 if the hydraulic system has not reached its preset level) and opening hydraulic valve 80. The high pressure fluid in line 67 then flows through bleeder line 82 (see FIG. 2) into sump 72.

As graphically illustrated in FIGURE 5, the force F with which manifold 12 bears against head .14 depends on the force caused by the weight of the manifold, F the force caused by the vacuum applied to the manifold through conduits 30, and, when applied, the upward force, F applied by hydraulic cylinder 46. Without the force supplying apparatus of the present invention, the total force F would continuously increase with increasing vacuum, as shown by dashed line 100. With the system of the present invention, as shown by solid line 102, the force increases from F until the hydraulic system is actuated at the illustrative predetermined vacuum level of 10" Hg, decreases by an amount equal to F and again increases from the lower end as the vacuum continues to rise. At all vacuum levels greater than 10" Hg, the total force is less, by an amount equal to F than it would be without the force supplying apparatus. The illustrative vacuum level of Hg has been chosen as the point at which the system is actuated on the basis of experiments which show that valve chatter does not generally occur until the vacuum reaches this level.

When the disclosed system is operating as above, in its automatic pressure relief mode, it is important that piston 50 be restrained so that the manifold 12 cannot accidentially be lifted off stationary head 14, e.g., by a sudden vacuum decrease. Stop adjust nut 56 and safety stop 58 are therefore adjusted to limit the piston advance to a small amount such as inch.

For valve cleaning and maintenance, when the manifold and head are to be separated, safety stop 58 and switch actuator 62 are removed so that piston 50 is free to move its full stroke, typically about 6". Needle valve 78 is then closed and hydraulic pump 68 actuated by closing manual operation switch 96 (see FIG. 3). The resulting force applied by piston 50 is greater than the weight of manifold 12 and therefore, moves the manifold vertically upward a distance equal to the full 6" stroke of the piston 50. As valve 78 in bleeder line 28 is closed, the manifold stays raised after switch 96 is released. To lower the manifold back onto head 14, needle valve 78 is opened and the high pressure fluid in line 67 drained through bleeder line 82 into sump 72.

FIGURE 4 illustrates an alternate hydraulic system 71' for use in the pressure relief system of the invention. System 71' is similar to previously disclosed system 71 and includes hydraulic lines 67 and 69 extending between pump 68 and cylinder 46, sump 72', pressure gauge 76', pressure switch 74', and needle valve 78' and solenoid operated hydraulic valve 80' in bleeder line 82'. Additionally, system 71 includes a differential pressure regulator 104 connected in shunt between high pressure line 67' adjacent inlet 64 of cylinder 46 and return line 69 and responsive through a relay 106 to the vacuum level at the inlet of pump 92 for varying the hydraulic pressure in line 69, and at the inlet of cylinder 46, in response to changes in the vacuum level. In practice, relay 106 and regulator 104 are adjusted so that, for all vacuum levels greater than the 10" Hg at which the system is actuated, the upward vertical force applied by piston 50 is equal to the downward force caused by vacuum in excess of 10 Hg so that the total force with which manifold 12 bears against head 14 remains constant. Whenever the vacuum level at pump 31 is at or below the cut-on level of 10" Hg, regulator 104 provides an open line between lines 67 and 69 and no force is applied by piston 50. As the vacuum level rises, relay 106 closes regulator 104 to establish a regulator back-pressure, thereby permitting the pressure in line 67' to build up to that pressure. The amount of regulator closure, and hence the regulator back-pressure and the pressure in line 67' at the cylinder inlet, depends on and varies according to the sensed vacuum level. In practice, high pressure hydraulic fluid produced by pump 68 flows through regulator 104 and is continuously recirculated so that the hydraulic pressure in line 67' at the cylinder inlet remains equal to the back-pressure established by the regulator.

The operation of regulator 104 is graphically illustrated in FIG. 6. As the vacuum level at pump 31 rises, the total force between manifold 12 and head 14 increases from F until, at 10" Hg, the pressure relief system is actuated. Lure shows the force F which would be present if the force applying apparatus were not in operation. With the apparatus in operation relay 106 and regulator 104 increase the pressure at the inlet of cylinder 46 as the vacuum level continues to rise above 10" Hg so that the upward force of piston 50 is equal to the downward force caused by the incremental vacuum in excess of 10" Hg, and the total force between the head 14 and manifold 12 (solid line 105), remains constant and equal to that existing at 10" Hg.

Other embodiments within the scope of the following claims will occur to those skilled in the art.

I claim:

1. In a valve including first and second members having ports therein arranged to communicate with each other at the interface of said members, said members being mounted for sliding movement with respect to each other along said interface, and suction apparatus for applying suction to at least one port of a member whereby said members are forced together, a pressure relief system for decreasing the force with which said members bear against each other, said system comprising:

force applying apparatus connected to one of said members for applying force to said one member in a direction to oppose the force caused by said suction;

and

an actuating system coupled with said force applying apparatus and responsive to said suction apparatus for controlling said force applying apparatus in accordance with change in the amount of suction applied by said suction apparatus.

2. The valve according to claim 1 wherein said actuating system activates and deactivates said force applying apparatus as the suction applied by said suction apparatus increases above and falls below a predetermined level respectively.

3. The valve according to claim 2 wherein said actuating system activates said force applying apparatus to apply a predetermined force to said one of said members and to maintain said force while the amount of said suction exceeds said predetermined level.

4. The valve according to claim 1 wherein said actuating system controls said force applying apparatus to apply to said one of said members force which increases and decreases as suction applied by said suction apparatus increases and decreases respectively.

5. The valve of claim 3 wherein said interface is substantially horizontal and said predetermined force applied by said force applying apparatus is applied to the upper of said members and is greater than the weight of the upper of said members.

6. The valve of claim 1 wherein said actuating system includes means for manually actuating said force applying apparatus to separate said members.

7. The valve of claim 1 wherein one of said members is mounted for rotatry movement relative to the other of said members, and said force applying apparatus includes a fluid pressure applying system connected to said one member for applying said force thereto.

8. The valve of claim 7 wherein said pressure applying system includes a relatively movable piston and cylinder operatively connected to said one of said members and which includes means detachably secured between said cylinder and piston for limiting the relative movement thereof to a distance substantially less than the full stroke thereof.

9. The valve of claim 1 wherein said force applying apparatus comprises a fluid pressure applying system for applying pressure to said one of said members, and said actuating system comprises electrical circuitry including a switch coupled to said fluid pressure applying system and said suction apparatus and responsive to said suction apparatus for actuating said fluid pressure applying system.

10. The valve of claim 9 wherein said fluid pressure applying system includes means coupled to said suction apparatus for varying the force applied by said fluid pressure applying system in response to variation in said suction.

11. The valve of claim 10 wherein said fluid pressure applying system includes a piston and cylinder relatively movable by said fluid pressure and operatively connected to said one of said members, and said means comprises a differential pressure regulator connected in shunt with said piston and cylinder.

References Cited UNITED STATES PATENTS 2,611,392 9/1952 Johnson.

ARNOLD ROSENTHAL, Primary Examiner US. Cl. X.R.

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