US3763893A

US3763893A - Pneumatic accumulator

Info

Publication number: US3763893A
Authority: US
Inventors: C Kriegel
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-04-03
Filing date: 1972-04-03
Publication date: 1973-10-09
Anticipated expiration: 1990-10-09

Abstract

A pneumatic accumulator which includes a housing and a reservoir for accumulating a volume of air under pressure. An air supply is provided through an orifice providing a controlled rate of filling the accumulator to line pressure. Air is bled from the reservoir at a slower rate. A slidable piston, operating a pair of diaphragms, closes off flow into the reservoir when operated. The piston is snap acting, moving to a second piston permitting the reservoir to fill but blocking drainage of the reservoir.

Description

United States Patent [191 Kriegel 1 Oct. 9, 1973 [54] PNEUMATIC ACCUMULATOR 3,601,155 8/1971 Brown l37/625.66

76 I t: CrlP.Ki l4018L k d, I men or a 2-25: woo Primary Examiner-Henry T. Kllnksiek Assistant Examiner-Robert J. Miller Flledi P 1972 Attorney-Donald Gunn et al. [21] Appl. No.: 240,685

. I [57] ABSTRACT [52] s CL l 137/625 6 A pneumatic accumulator which includes a housing [5.1] Im- CL 6k 31/38'5 and a reservoir for accumulating a volume of air under [58] Field of 137/325 6 625 66 pressure. An air supply is provided through an orifice 137/625 65 27 providing a controlled rate of filling the accumulator to line pressure. Air is bled from the reservoir at a [56] References Cited slower rate. A slidable piston, operating a pair of diaphragms, closes off flow into the reservoir when oper- UNITED STATES PATENTS ated. The piston is snap acting, moving to a second Dyson piston permitting the reservoir to but blocking 3,076,477 2/1963 Brandenberg. 137/625.6 drainage of the reset-vow 3,470,910 10/1969 Loveless l37/625.6 3,653,408 4/1972 Coiner 137/625.6 10 Claims, 2 Drawing Figures PNEUMATIC ACCUMULATOR BACKGROUND OF THE INVENTION In pneumatic systems, various pneumatic signals are formed. One of the more common pneumatic signals is that from an accumulator. In time past, accumulators have had the form of a large tank typically vented into the system through a timed control valve. This serves quite well as a less than precision pressure accumlator, but in some instances, this is not sufficiently precise or accurate to meet the needs of a pressure accumulator. Precision pressure accumulators have not heretofore been readily available. The present invention, however, is an apparatus which forms a precision pressure accumulator which accumulates a measured volume of air or other pneumatic fluid at a predetermined pressure and which thereafter, vents this air on the formation of a mechanical signal to the accumulator. The air is accumulated to line pressure and is vented to a predetermined lower pressure. The precision of the operation is believed to manifest upon a description of the preferred embodiment.

SUMMARY OF THE INVENTION The present invention is summarized as a housing having a chamber is connected with an inlet providing a pneumatic fluid at a predetermined level. The inlet communicates past a seat which is closed by a diaphram moved by a piston. When the diaphram and piston are away from the seat, pressure fluid enters the structure flowing past the seat and then through a control orifice. The orifice controls the rate at which the accumulator is filled. The chamber in the accumulator is drained by means of a passage which connects to a second seat. The second seat is closed by the above mentioned piston. The piston is kept in one of two positions by means of pressure differential forces. Differential pressure forces the piston to a first position clearing the first seat and permitting filling'of the reservoir. Once the reservoir has been filled, the reservoir pressure itself is made available for application to the opposite end of the piston. When the piston is moved by. a mechanical leakage to actuate discharge, it closes off the first valve seat, permitting the reservoir to be exhausted without further filling from the supply line. Reservoir pressure is then used on the opposite face of the piston to maintain the piston in a position preventing filling of the reservoir while permitting depletion of the chamber through an outlet line.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENT Attention is first directed to FIG. 1 of the drawings where the pressure accumulator is indicated by the numeral 10. It comprises a body 12 which has a hollow cavity 14. The cavity is very substantial in size. The cavity 14 is sealed by means of a bottom plate 16 which is joined to the body by means of a number of bolts 18.

The seal between the bottom-plate 16 and the body 12 is made leak proof by means of a o-ring 20 which is positioned in a groove encircling the bottom plate 16. The cavity 14 includes the indention in the bottom plate 16. The cavity 14 preferably is a rather precisely calculated cavity. This permits the present invention to accumulate a precisely measured volume of pneumatic fluid.

The pressure accumulator is formed of other components. The body 12 is positioned adjacent to a first diaphram 22. The diaphram 22 is immediately adjacent to a second body member 24. The body member 24 is positioned immediately adjacent to a second diaphram 26. A cap plate 28 is positioned on top of the diaphram 26 and positions a mechanical actuator 30. The actuator initiates operation of the pressure accumulator as will be described. A piston assembly generally indicated at 32 is movable within the second body member 24 and the body cap 28. The piston 32 is connected to the second diaphram 26 which is manipulated on movement of the piston 32.

After identifying the major components of the assembly, attention is next directed to the passages and valve seats which will be described to thereby set forth the method'of assembly and operation of the pressure ac-- cumulator 10 of the present invention. The numeral 40 identifies a pressure inlet. The pressure inlet 40 is a threaded opening adapted to be communicated with a pressure source. The inlet 40 communicates with a passage 42 which emerges just below the first diaphram 22. The passage 42 emerges at an opening 44 which will be termed a valve seat for reasons to be set forth hereinafter. The opening 44 is at the top end of the body member 12. A second passage 46 is a short distance from the opening 44. The

passages

42 and 46 emerge just below the diaphram 22. The passage 46 then communicates with a needle valve 50. The device 50 includes a needle valve body supported on an o-ring movable in a tapered hole or opening which is connected to the passage 46. The valve 50 thus controls the flow of pressure fluid from the passage 46 through a second passage 52. In other words, air or other pneumatic fluid is introduced through the passage 42 and moves into the second passage 46. The flow or rate of the pneumatic fluid is controlled by the position of the needle valve assembly 50. The flow enters into the chamber 14 through the passage 52 after being regulated by the needle valve 50.

To this juncture, an arrangement has been described whereby the chamber 14 is filled from the pressure line. The chamber 14 is vented by a passage 60 which passage extends through the body member 12, the body member 24 and into the cap assembly 28. The passage 60 terminates above the second diaphram 26. The pas-- sage 60 is in communication with a facing shoulder 62 formed interiorially of the cap assembly 28. The shoulder 62 serves as a valve seat and will be denoted hereinafter as the second valve seat. The valve seat functions in cooperation with the piston 32 to open or close the valve seat to the flow of pressure fluid from the passage 60. The piston 32 functions as a valve member when it is contacted against the shoulder 62. This is shown in FIG. I while FIG. 2 shows the piston 32 at its downward position, thereby leaving the valve seat open for The chamber 14 is thus vented by a flow of pressure fluid through the passage 60 past the valve seat 62. The flow is directed into a small cavity 66. The cavity 66 is in communication with a passage 68 which communicates with a threaded port 70. The calibrated or precisely measured pressure signal is exhausted to other connective lines in the pneumatic system at the port 70. It will be observed that the mechanical actuator 30 is also positioned in the cavity 66 but this presents no particular problem because the cavity is oversized for this purpose.

The cavity 66 also communicates through a passage 72 to a tapered opening and a needle valve assembly 74. The needle valve assembly 74 is similar to the needle valve assembly 50 previously mentioned. It includes a threaded screw which is connected with a tapered needle valve which is positioned with respect to a tapered passage. When the needle valve is opened, fluid pressure is vented to atmosphere through a passage 76. The passage 76 is thus in communication with the passage 60 by means of the needle valve 74.

Attention is next directed to the make up of the piston 32. The piston 32 is preferably comprised of a pair of

members

86 and 88. They are positioned on opposite sides of the second diaphram 26. They are joined together by means of a bolt 90 which taps into the member 88. The bolt 90 pulls the

members

86 and 88 together to clamp the diaphram 26.

The member 86 is grooved about its top periphery and carries an o-ring 92 which cooperates with the shoulder 62 to form a pressure tight seal. It will be recalled that the shoulder 62 serves as a valve seat. The lower member 88 moves within an internal cavity formed in the body member 24. The cavity is vented to atmosphere and a passage 94 is provided for that purpose. The drawing illustrates the piston 32 being in contact with the diaphram 22 in both positions. However, the two members are not joined together but rather, the diaphram 22 is forced upwardly against the piston 32. Hence, the piston 32 bears at all times on the diaphram 22 and forces the diaphram 22 downwardly in change of position of the piston as shown in FIG. 1 and FIG. 2 when considered jointly.

In operation, the device is filled in the following manner. A supply line is connected to the fitting 40 and an outlet line is connected to the fitting 70. Pressure fluid is supplied at a stated pressure through the fitting 40 and flows through the first passage 42 and past the valve seat 44 to enter the passage 46. This is accomplished with the diaphram 22 in the up position as illustrated in FIG. 1. The pneumatic fluid flows into the passage 46 and then into the cavity 14 under regulation of the needle valve 50. The needle valve includes a threaded body which is preferably moved by means of a screw driver adjustment to different positions, thereby positioning the tapered needle valve in the tapered passage to control the rate of admission of pressure fluid to the cavity 14. If the needle valve is moved to the right as shown in FIG. 3, the cavity 14 fills faster. As will be observed, it functions somewhat as an adjustable orifice regulating the rate of flow into the cavity 14. The cavity 14 is filled. The only route for pressure fluid from the cavity 14 is through the passage 60. However, this passage 60 is blocked by the position of the piston 32 which closes the valve seat 62 previously described.

Once the cavity 14 has been filled, the piston remains in the up position illustrated in FIG. 1. The pressure accumulator is discharged by operation of the mechanical switch 30 which will be described in detail. The pressure accumulator can remain filled for an indefinite period of time without encountering any problems whatsoever. In any case, once the cavity is filled, the apparatus is ready for discharge.

Discharge of the pressure accumulator is achieved by momentarily depressing the push button switch 30. As the switch 30 is pushed down, it contacts the bolt 90 and forces the piston 32 downwardly. When the piston 32 moves downwardly, it forces the diaphram 22 against the valve seat 44. This closes the inlet passage from the chamber 14. Fluid can no longer enter the chamber 14 and fill the accumulator to line pressure. The piston 32 stays in the down position, nowithstanding release of the pushbutton 30. In other words, if the device forms a pressure signal which lasts many seconds or minutes, the pushbutton 30 need only be depressed momentarily and subsequently released. The piston 32 stays in the down position because the upper end or face of the piston is exposed to a higher pressure and has a larger surface area. The upper end of the piston is thus exposed to the pressure within the chamber 14 through the passage 60. The force acting on the upper face of the piston 32 is therefore larger than the force acting on the lower face. Viewing FIG. 1 and FIG. 2 together, it will be observed that the lower face has a smaller surface area. The smaller surface area is normally exposed to line pressure. However, movement upwardly and downwardly further reduces the amount of area exposed to line pressure. FIG. 1 illustrates the piston in the up position at which point the entire lower face of the piston 32 is exposed to line pressure. However, when it is in the down position as shown FIG. 2, the lower face area is equal to the cross sectional area of the passage 42. There is not an adequate force to overcome the force acting at the upper end and hence, the piston stays in the down position for a measured interval of time.

In operation, the needle'valve is first adjusted. This controls the rate of filling the chamber 14. As soon as pressure is applied through the inlet 40, the piston is forced upwardly, blocking the chamber 14 against further drainage and tending to fill the reservoir. The filling is subject to a rate of control determined by the needle valve 50. Once it has been filled, the chamber 14 rides at supply pressure.

When the pushbutton 30 is momentarily depressed,

I the exposure of the upper face of the piston 32 to preslarger surface area than the lower end. As a consequence, the force acting on the upper end of the piston, holds the piston in the down position. This is terminated when the pressure in the chamber 14 falls to a certain level. When the piston is in the down position, the supply is disconnected from the reservoir 14 and the reservoir 14 eventually is reduced in pressure close to outlet line pressure. The bottom pressure depends on the upstream restrictions from the fitting in part and also on the position of the needle valve 74. As shown in FIG. I the needle valve 74 controls the rate of discharge of the chamber 14 or, in other words, it controls the timed discharge of the pressure accumulator 10 of the present invention. It provides fine tuning, so to speak, which enables the device to function in a more precise manner. Thus, the accumulator discharges a precisely measured volume of air.

The foregoing is directed to the mode of operation of the preferred embodiment. The preferred embodiment is assembled of the various components which are shown in the drawings. Many alterations and variations in the structure can be adapted and may be implemented with relative ease. However, the preferred embodiment is that illustrated in the drawings. The scope of the present invention is determined by the claims which are appended hereto.

1 claim:

1. A pressure accumulator comprising:

a body having a closed cavity therein;

a passage in said body connected to said cavity and having an opening which is adapted to be connected to a pressure source;

a valve in said passage and cooperatively arranged with respect to a valve seat to control flow in said passage;

a second passage connected from said cavity to an outlet which is adapted to be connected with a line for using a pneumatic signal;

a second valve in said second passage and cooperatively arranged with respect to a valve seat to control flow in said second passage;

means connected to said first and second valves for operating them, said means being responsive to pressure within said cavity in its operation, and comprising a piston having two opposing faces;

said first face being arranged for exposure to a first pressure level within said body;

said second face being arranged for exposure to a second pressure level within said body;

and wherein said second pressure level is a function of the pressure within said cavity and is adapted to decay therewith after operation of said last named means;

said first and second faces being exposed to forces holding said piston in a second position for an interval and subsequently moving said piston from the second position to the first position after pas sage of an interval of time; and,

means operable to move said piston from the first to the second position.

2. A pressure accumulator comprising:

a body having a closed cavity therein;

means connected to said first and second valves for operating them, said means being responsive to pressure within said cavity in its operation, and comprising a movable piston;

said first valve comprising a portion of said movable piston;

a diaphram between said movable piston and said first valve seat and cooperatively arranged to close said first passage to the flow of pressure fluid therethrough;

said first valve seat comprising a facing shoulder adjacent to said diaphram and including a pair of openings in said shoulder facing toward said diaphram and adapted to be seated thereby, said openings being in portions of said first passage;

a chamber in said body for receiving said piston therein;

a shoulder in said chamber facing said piston, said shoulder comprising said second valve seat and said piston comprising said second valve;

said second passage extending to said chamber on one side of said piston and opening from the opposite side with said shoulder interposed between to control flow through said passage; and,

actuator means extending into said chamber for mov-' ing said piston away from said shoulder to open said second valve, and to close said first valve by placing said diaphram in sealing contact with said facing valve.

3. The structure of claim 2 including a needle ,valve in said passage to regulate the rate of flow therethrough.

4. The structure of claim 2 including a needle valve connected from said second passage and vented to an outlet to regulate the rate of flow from said cavity.

5. The structure of claim 2 wherein said piston is movably positioned with said chamber, and said chamber is closed at one side thereof by a second diaphram which is connected to said piston.

6. The structure of claim 5 wherein said body is formed of multiple components and said second diaphram is clamped between two components.

7. The structure of claim 2 wherein said piston has a first face which is not exposed to pressure in said secand passage when said piston is in a first position and which is exposed when said piston is in a second position, said face being limited in exposure when said shoulder in said chamber is contacted by said piston.

,8. The structure of claim 7 including a seal means arranged between said face and said shoulder.

9. The structure of claim 7 including a second diaphram in said chamber closing said chamber at one side thereof.

10. The structure of claim 7 including a needle valve assembly connected from said chamber to an outlet, said needle valve assembly being connected at a point in said chamber where said second valve prevents flow therethrough said needle valve assembly when said piston is in sealing contact with said shoulder in said chamber.

Claims

1. A pressure accumulator comprising: a body having a closed cavity therein; a passage in said body connected to said cavity and having an opening which is adapted to be connected to a pressure source; a valve in said passage and cooperatively arranged with respect to a valve seat to control flow in said passage; a second passage connected from said cavity to an outlet which is adapted to be connected with a line for using a pneumatic signal; a second valve in said second passage and cooperatively arranged with respect to a valve seat to control flow in said second passage; means connected to said first and second valves for operating them, said means being responsive to pressure within said cavity in its operation, and comprising a pIston having two opposing faces; said first face being arranged for exposure to a first pressure level within said body; said second face being arranged for exposure to a second pressure level within said body; and wherein said second pressure level is a function of the pressure within said cavity and is adapted to decay therewith after operation of said last named means; said first and second faces being exposed to forces holding said piston in a second position for an interval and subsequently moving said piston from the second position to the first position after passage of an interval of time; and, means operable to move said piston from the first to the second position.

2. A pressure accumulator comprising: a body having a closed cavity therein; a passage in said body connected to said cavity and having an opening which is adapted to be connected to a pressure source; a valve in said passage and cooperatively arranged with respect to a valve seat to control flow in said passage; a second passage connected from said cavity to an outlet which is adapted to be connected with a line for using a pneumatic signal; a second valve in said second passage and cooperatively arranged with respect to a valve seat to control flow in said second passage; means connected to said first and second valves for operating them, said means being responsive to pressure within said cavity in its operation, and comprising a movable piston; said first valve comprising a portion of said movable piston; a diaphram between said movable piston and said first valve seat and cooperatively arranged to close said first passage to the flow of pressure fluid therethrough; said first valve seat comprising a facing shoulder adjacent to said diaphram and including a pair of openings in said shoulder facing toward said diaphram and adapted to be seated thereby, said openings being in portions of said first passage; a chamber in said body for receiving said piston therein; a shoulder in said chamber facing said piston, said shoulder comprising said second valve seat and said piston comprising said second valve; said second passage extending to said chamber on one side of said piston and opening from the opposite side with said shoulder interposed between to control flow through said passage; and, actuator means extending into said chamber for moving said piston away from said shoulder to open said second valve, and to close said first valve by placing said diaphram in sealing contact with said facing valve.

3. The structure of claim 2 including a needle valve in said passage to regulate the rate of flow therethrough.

7. The structure of claim 2 wherein said piston has a first face which is not exposed to pressure in said second passage when said piston is in a first position and which is exposed when said piston is in a second position, said face being limited in exposure when said shoulder in said chamber is contacted by said piston.

8. The structure of claim 7 including a seal means arranged between said face and said shoulder.