GB2451146A

GB2451146A - Calibration pump with manually operated combined pressure adjusting and release mechanism

Info

Publication number: GB2451146A
Application number: GB0717093A
Authority: GB
Inventors: Cary Ratner
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-07-20
Filing date: 2007-09-04
Publication date: 2009-01-21
Anticipated expiration: 2027-09-04
Also published as: GB0717093D0; DE102008003167A1; DE102008003167B4; GB2451146B

Abstract

A hand operated hydraulic calibration pump comprises a main housing (1, fig 2) having a reservoir 2 and pump (3) for pumping fluid from the reservoir 2 to a second chamber 4 and test point outlet 5. Activation of the pump is carried out via squeezing handles (3, 4) together to operate a piston (not shown) inside pump housing 61. The pump further comprises a combined pressure adjusting and pressure release mechanism 6 for making small adjustments to the pressure in the second chamber 4. Mechanism 6 is operated by concentric knobs 29, 34 with release control knob 34 extending from pressure control knob 29 so as to be located in a cavity 50 defined by an end of the knob 29. The pump further comprises an integral excess pressure relief valve (7) for releasing excess pressure in chamber 4, the relief valve operable across the entire range of pressures at which the pump operates. Inlet (13) and outlets 5, 19 have meshes that filter the fluid. In other embodiments an extent of movement of the handles may be adjusted and a passage in a pick-up tube may be parallel to a central bore.

Description

HYDRAULIC CALIBRATION PUMP

This invention relates to a hydraulic pump to be used for the calibration and testing of pressure sensors.

An embodiment of the invention will now be described, by example only, with reference to the accompanying drawings, in which:-Figure 1 is a side view of a hand operated hydraulic pump in accordance with an embodiment of the invention; Figure 2 is another side view of a hydraulic pump in accordance with the embodiment of the invention; Figure 3 is a cross-sectional view of the main body of the hydraulic pump shown in Figures 1 and 2; Figure 4 is a cross-sectional view of the main body of the hydraulic pump shown in Figures 1 and 2 in a plane at right angles to that of Figure 3: Figure 5 is a cross-sectional view of the piston and fill valves of the pump shown in Figures 1 and 2; Figure 6 is cross-sectional view of an excess pressure relief valve of the pump of Figures 1 and 2; Figure 7 is a cross-sectional view of a Vernier adjusting knob of the pump shown in Figures 1 and 2; and Figures 8 to 14 are repeats of Figures 1 to 7 but with reference numerals that link each component shown to the component listed in the

associated tables.

Referring to the Figures, the hand operated hydraulic pump comprises a main housing 1 that comprises a reservoir 2 with transparent tapered wall and pump 3 for pumping fluid from reservoir 2 to a second chamber 4 and test point outlet 5. Activation of the pump is carried out via squeezing handles 3, 4 together to operate a piston (not shown) inside pump housing 61. The pump further comprises a combined pressure adjusting and pressure release mechanism 6 for making small adjustments to the pressure in the second chamber 4 and an integral excess pressure relief valve 7 for releasing excess pressure in chamber 4.

The pump 3 comprises the pump housing 61 that defines a central bore 8 in which a piston (not shown) can be moved longitudinally to pressurise fluid in bore 8. The bore 8 has an outlet 9 through which fluid can be forced into the second chamber 4. The flow of fluid through outlet 9 is controlled by check valve 10. Check valve 10 comprises a valve member 11 that is urged against valve seat 17 by a spring 12 and the pressure of fluid in chamber 4. The bore 8 also has an inlet 13 that is in communication with reservoir 2 via a pick-up tube 14 that is aligned parallel to bore 8. Fluid flow from the pickup tube 14 to bore 8 through the inlet 13 is controlled by a poppet valve 15 that provides directional control of fluid flow allowing fluid to flow into bore 8. At end 18 of pick-up tube 14 is a mesh 19 that acts to filter fluid entering the pick-up tube 14 and therefore, bore 8.

The piston (not shown) is connected to piston rod assembly 70 that is movable under actuation of the handles 3, 4 to drive the piston. Piston rod assembly 70 comprises a shaft 71 engaged, such as by a screw thread, with a fastener 72 such that the location of fastener 72 is adjustable along the shaft 71. Fastener 72 at its end 73 has a flange 74 that is pivotally connected to an end of arms 75, 76, the other ends of the arms 75, 76 being connected to handles 3, 4.

Drawing of the piston towards end 16 of the pump housing 6 (by allowing the handles 3, 4 to move apart) opens poppet valve 15 and draws fluid from reservoir 2 into bore 8 via pick-up tube 14. Infiltration of dirt to the pump 3 is prevented by mesh 19. Squeezing of the handles 3, 4 together forces the piston into the bore 8 away from end 16, increasing fluid pressure in bore 8. The poppet valve 15 prevents fluid from flowing back into reservoir 2 and as the pressure in bore 8 increases under action of the piston it exerts a force on valve member 11 of check valve 9.

When the pressure in bore 8 applies a force on valve member 11 that is greater than the opposing force applied to the valve member 11 by the fluid pressure in chamber 4 and spring 12, the valve member 11 is caused to lift from seat 17 to allow fluid to flow from bore 8 into chamber 4.

Check valve 10 prevents the return of fluid to bore 8 from chamber 4. In this way, the pump 3 can be used to increase fluid pressure in chamber 4.

Priming of the pump may require significant force to be applied to handles 3, 4 to remove air entrained in the fluid. To make it easier for the user to prime the pump, the user can adjust fastener 72 to draw handles 3, 4 together shortening the stroke (extent of movement of the handles) to actuate the pump. It is believed that this provides an ergonomic advantage with the user being able to apply a greater force to the handles 3, 4 when they are close together.

Second chamber 4 comprises a series of passageways that connect test point outlet 5, pressure gauge outlet 19, pressure adjustment mechanism 6 and pressure relief valve 7. Test point outlet 5 is for connecting chamber 4 of the hydraulic pump to a device to be calibrated. Pressure gauge outlet 19 is for connecting chamber 4 to a device for measuring the pressure in chamber 4. Test point outlet 5 and pressure gauge outlet 19 are provided with meshes 37, 38 that filter fluid passing into and out of chamber 4 via these outlets 5, 19.

In use, the pressure in chamber 4 can be finely adjusted using mechanism 6 which can be operated to make small adjustments to the volume of chamber 4 and therefore, the pressure in chamber 4. Mechanism 6 comprises a main body 20 having a central bore 21 in which is provided a piston 22 slidable within bore 21. Piston 22 has a narrow neck 24 defining a central passageway 25 that is in communication with chamber 4, the neck 24 broadening out to define a bore 26 housing a shaft 23 that is slidable relative to the walls of the piston 22. Shaft 23 has a V-shaped end 27 that abuts a ball 28 that is trapped between end 27 of shaft 23 and the end of neck 24. In a wall of the piston 22 there is provided a passageway 32 that connects passageway 25 to reservoir 2. In one condition ball 28 seals passageway 32 and chamber 33 from passageway 25 and in another condition the passageways 32 and 25 are in fluidic communication.

Mechanism 6 further comprises an adjustment control knob 29 having at one end 30 a screw thread that engages with a complimentary screw thread on the main body 20 with the other end 84 of knob 29 comprising a flattened loop that defines a square shaped cavity 50. The knob 29 further comprises an inner annular abutment 31 that engages with an outer annular projection 62 on the piston 22 to regulate the extent of movement of piston 22 out from the main body 20.

Connected to an end of the shaft 23 is a release control knob 34. The knob 34 is arranged to extend from knob 29 so as to be located in cavity defined by the end of knob 29. In this embodiment, knob 34 is located so as to be concentric with knob 29 (i.e. located around a common centre). By this arrangement, the user can operate both control knobs 39, 34 with the same hand. Furthermore, end 84 of knob 29 protects knob 34 from impacts that could cause damage to the pump, such as breaking of shaft 23.

In use, piston 22 can be caused to slide inwardly and outwardly of the main body 20 by adjusting the knob 29 thereby varying the volume defined by passageway 25 and the central bore of main body 20. In the event that the user wishes to release the pressure in chamber 4, the user can pull knob 34 outwardly, moving shaft 23 away from the neck of piston 22, allowing ball 28 to move under the fluid pressure in chamber 4 away from passageway 32 such that fluid in chamber 4 is released to reservoir 2 via passageways 25 and 32.

Excess pressure relief valve 7 comprises a housing 40 and a piston 41 movable in the housing 40. The end 45 of piston 41 has an 0- ring 46 that cooperates with valve seat 44 to regulate flow of fluid from chamber 4.

Movement of the piston 41 is regulated by a cap 42 that is connected to the housing 40 by a screw thread 43. Piston 41 is urged towards seat 44 by Belleville washers 81, 82. By adjusting the cap 42 it is possible to set the sealing pressure of 0-ring 46 with seat 44 and therefore, the maximum possible pressure in chamber 4 before fluid pressure overcomes the seal formed by the 0-ring 46 and seat 44 and is vented to the atmosphere. The pressure relief valve 7 can operate across the entire operable range of the pump, typically 0 to 68x106 Pascals (1O,000psi).

The reference numerals in Figure 9, Figure 10 and Figure 11 correspond to the components listed in the following table: ITEM P/N DESC QTY 23 PP-0131 WASHER, SEALING, 1/4 BSPP 1 22 8-32 X 1/2 SHCS SS 3 21 10-32 X 5/8 SHCS SS 1/4-20 X 3/8 LOW HEAD SS 2 19 PP-0339 0-RING, 1/16 X 3/8 1 18 PP-0135 0-RING, 1/16 X 1/2 1 17 PP-0337 WASHER, SEALING, 3/8BSPP 1 16 PP-0317 TEST POINT 1 PP-0316 FILTER, MESS. .44 1 14 PP-0314 FILTER, MESH, .59 1 13 PP-0313 0-RING, 1/16 X 5/8 1 12 PP-0312 WASHER, NYLON 2 11 20-2060 PLUG, FILL PORT 1 20-2032-1 ADP, GAUGE,3/8MX1/4NPTF 1 9 20-2031 MAIN HOUSING 1 8 20-2050 ASM, VERNEIR ADJUST 1 7 20-2040 ASM, PISTON DRIVE 1 6 20-2020 ASM, PRESSURE RELIEF 1 20-2010 ASM, PUMP/FILL VALVE 1 4 PP-0302 0-RING, 1/16 X 2 3/8 2 2 20-2015A END CAP, RESERVOIR 1 1 20-2014A RESERVOIR 1 The reference numerals in Figure 12 correspond to the components listed in the following table: ITEM P/N DESC QTY 10-32 x 5/8 SHCS SS 2 14 PP-0331 0-RING, 1/16 X 1 3/8 1 13 PP-0131 WASHER, SEALING, 1/4BSPP 1 12 PP-0329 WASHER, SEAL, 1/8" 1 11 PP-0328 0-RING, 1/16 X 3/8 1 PP-0315 FILTER, MESH, .375 1 9 PP-0327 SNAP RING, INT, .375 1 8 PP-0309 SPRING, CHECK VALVE 2 7 PP-0307 0-RING, MAIN CHECK 1 6 20-2019 TUBE, PICK-UP 2 20-2055 VALVE, MAIN CHECK 2 4 20-2018 HOUSING, PICK-UP 1 3 20-2017 HOUSING. PUMP 1 2 20-2012A HOUSING, FILL VALVE 1 The reference numerals in Figure 13 correspond to the components listed in the following table: ITEM P/N DESC QTY 7 PP-0301 0-RING, 4mmID x 1mm 1 6 PPO131 WASHER, 1/4 BSPP 1 5 PP-0310 WASHER, BELLEVILLE TBD 4 PP-0311 3/16 BALL, ST STL 1 3 20-2023 HOUSING 1 2 20-2022 CAP 1 1 20-2021 PISTON, PRES RELIEF 1 The reference numerals in Figure 14 correspond to the components listed in the following table:

ITEM PIN DESC QTY

17 PP-0341 0-RING, 3mm ID X 1mm 1 16 8-32 X 3/16 CUP POINT (SS) 3 WASHER, AN960-C816L 1 13 PP-0333 SNAP RING, "C", .50 1 12 PP-0131 WASHER, 1/4 BSPP 1 11 PP-0311 BALL, 3/16, SS 1 PP-0332 8-32 X 3/16 DOG PT (SS) 3 9 PP-0322 0-RING, HI PRESSURE 1 8 PP-0321 WASHER, BACKUP 1 7 PP-0135 0-RING 1/16 X 1/2 OD 1 6 20-2057 WASHER, THRUST 1 20-2056 KNOB, RELEASE 1 4 20-2054 BODY, VERNIER 1 3 20-2053 SHAFT, PRESSURE RELEASE 1 2 20-2052 PISTON, VERNIER 1 1 20-205 1 KNOB, VERNIER 1

Claims

I CLAIMS

1. A hydraulic calibration pump comprising a pump for pumping fluid from a fluid reservoir to a chamber, an adjustment mechanism for making adjustments to the volume of the chamber to control the pressure in the chamber, the adjustment mechanism operated by an adjustment control, and a pressure release mechanism for releasing pressure in the chamber by selectively connecting the chamber to the fluid reservoir, the pressure release mechanism manually operated by a pressure release control that is mounted so as to extend out from the adjustment control.

2. A hydraulic calibration pump according to claim 1, wherein the adjustment control has a cavity therein in which the pressure release control is located.

3. A hydraulic calibration pump according to claim 1 or claim 2, wherein the pressure release control is concentric with the adjustment control.

4. A hydraulic calibration pump comprising a pump for pressurising fluid in a chamber, the pump comprising an inlet and the chamber comprising at least two outlets, wherein the inlet and the at least two outlets are provided with filters for filtering fluid passing therethrough.

5. A hydraulic calibration pump according to claim 4, wherein the chamber comprises an outlet for connecting the pump to a device to be calibrated and an outlet for connecting the pump to a gauge, each outlet having a filter for filtering fluid passing therethrough.

6. A hydraulic calibration pump comprising a pump for pressurising fluid in a chamber, the pump having an inlet for fluid, the inlet connected to a fluid reservoir having tapered walls that are transparent or translucent.

7. A hydraulic calibration pump comprising a pump for pressurising fluid in a chamber and at least one movable handle for operating the pump, wherein the extent of movement of the at least one handle can be adjusted.

8. A hydraulic calibration pump comprising a pump for pressurising a fluid in a chamber and an integral pressure relief valve for releasing fluid from the chamber when the fluid pressure increases above a predetermined level, wherein the pressure relief valve can be adjusted to alter the predetermined level at which fluid is released from the chamber.

9. A hydraulic calibration pump comprising a pump for pressurising a fluid in a chamber and a pressure relief valve for releasing fluid from the chamber when the fluid pressure increases above a predetermined level, wherein the pressure relief valve can be adjusted to alter the predetermined level at which fluid is released from the chamber and is operable across an entire range of pressures at which the pump operates.

10. A hydraulic calibration pump comprising a pump for pressurising a fluid in a chamber and a pressure relief valve for releasing fluid from the chamber when the fluid pressure increases above a predetermined level, wherein the pressure relief valve can be adjusted to alter the predetermined level at which fluid is released from the chamber, the pressure relief valve comprising a piston operable with a valve seat to control the release of fluid, wherein the piston is urged towards the valve seat by at least one Belleville washer.

11. A hydraulic calibration pump comprising a pump for pressurising a fluid in a chamber, the pump having a central bore in which a piston is operable to pump fluid from an inlet to an outlet, the inlet being connected to a reservoir via a pick-up tube, wherein the passageway of the pick-up tube is parallel to central bore.

12. A hydraulic calibration pump substantially as described herein with reference to the accompanying drawings.