PORTABLE PRESSURE GAUGE TESTER

Abstract: A pressure testing and calibrating apparatus comprising: a fluid filled pressure vessel (2) including an observation port and a sealable glass hatch (3); a pump means (9) attached to or integral with said pressure vessel (2) and connected for fluid flow communication therewith, to raise the pressure within said vessel (2) above ambient; a means (12) to release the raised pressure within said vessel (2) prior to unsealing said hatch (3); and a means (13) to accurately ascertain the pressure within said vessel (2). The instrument to be calibrated is paced in the vessel (2).

Description: Title: "PORTABLE PRESSURE GAUGE TESTER" Background of the Invention Field of the Invention The present invention relates to pressure gauge testing apparatus. Such apparatus are primarily used in testing laboratories to calibrate or re-calibrate pressure measuring instruments, but can also be used to ascertain the ability of other instruments to withstand high pressures. An object of the present invention is to enable calibrations and tests to be done, remote from the usual testing laboratories, by providing an accurate portable pressure testing apparatus. Summary of the Invention The present invention consists in a pressure testing and calibrating apparatus comprising: a fluid filled pressure vessel including an observation port and a sealable hatch; a pump means attached to or integral with said pressure vessel and connected for fluid flow communication therewith, to raise the pressure within said vessel above ambient; a means to release the raised pressure within said vessel prior to unsealing said hatch; and a means to accurately ascertain the pressure within said vessel. Preferably said hatch includes said observation port. Brief Description of the Drawings A preferred embodiment of the invention will now be described by way of example only with reference to the accompanying drawing being; an exploded perspective view of a pressure testing apparatus according to the invention. Description of the Preferred Embodiments Referring to the drawing, a water filled pressure vessel comprises an upstanding cylindrical pot 2, closed at one end and a circular toughened glass hatch 3 adapted to sealingly engage an open end of the pot 2. An annular locking collar 4 includes a plurality of circumferentially spaced, inwardly radially projecting screw-down flanges 5, mutually interengageable with respective outwardly radially projecting screw-down flanges 6, disposed adjacent the open end of the pot 2. The collar 4 is thus adapted to clampingly engage the hatch 3 with the open end of the pot 2 upon rotation relative to the pot 2, so as to seal thereagainst by way of a sealing gasket or ring 7. However any suitable sealing means may be used. The glass hatch 3 has a convex surface 8 adapted to displace most of the air from the pot 2 upon engagement therewith when the pot is substantially full of water. The purpose being to expel air from within the pressure vessel which would otherwise impede its efficient pressurisation. The convex glass hatch provides a magnified image of the contents of the vessel. A positive displacement piston and cylinder type hand operable pump 9 of the type commonly used in hydraulic car jacks, is attached to the pot 2 and is connected therewith for fluid flow communication. Repeatedly depressing a pump piston 11 causes water to flow unidirectionally by way of a non-return valve into the vessel 1 from a pump reservoir, thus compressing any residual air and raising the pressure within the vessel 1. Alternatively, the pump may comprise a screw-down piston and cylinder in the manner of a syringe, in which case, rotation in one direction may cause pressurization whilst rotation in the opposite direction will cause depressurization. Opening a valve 12 allows the pressurised water within the pressure vessel to flow back into the reservoir under the action of the compressed air. A pressure gauge in the form of an arcuate air filled capillary tube 13 is disposed within the glass hatch and when in use provides a measure of the pressure in the pot 2. However, any suitable type of pressure gauge which can be read through the hatch or from a remote indicator may be used. In operation the pot 2 is filled with water and an instrument to be calibrated is placed in the pot. The hatch 3 is fitted to the pot 2 and secured by rotation of the locking collar 4 relative to the pot. The valve 12 is closed by clockwise rotation and the pump is operated until a desired pressure within the pot is reached, as indicated by the capillary tube 13. This value is then compared with that indicated by the instrument as seen through the hatch. Repeating this procedure at various pressures enables a measure of the instruments inaccuracy to be determined over a range of pressures.

Claims: CLAIMS 1. A pressure testing and calibrating apparatus comprising: a fluid filled pressure vessel including an observation port and a sealable hatch; a pump means attached to or integral with said pressure vessel and connected for fluid flow communication therewith, to raise the pressure with said vessel above ambient; a means to release the raised pressure within said vessel prior to unsealing said hatch; and a means to accurately ascertain the pressure within said vessel. 2. A pressure testing and calibrating apparatus according to claim 1 wherein said hatch includes said observation port. 3. A pressure testing and calibrating apparatus according to claim 2 wherein said hatch is transparent. 4. A pressure testing and calibrating apparatus according to claim 3 wherein said hatch is fabricated from toughened glass. 5. A pressure testing and calibrating apparatus according to any of the preceding claims wherein said hatch has a cover surface. 6 A pressure testing and calibrating apparatus according to any of the preceding claims wherein said hatch is releasably sealed to said vessel by an annular locking collar including a plurality of circumferentially spaced inwardly radially projecting screw-down flanges, mutually interengageable with respective outwardly projections, screw-down flanges of said vessel; said collar being effective to clamp a sealing ring or gasket between said vessel and said hatch to thereby seal said vessel. 7. A pressure testing and calibrating apparatus according to any one of the preceding claims wherein said pump means is a positive displacement pump. 8. A pressure testing and calibrating apparatus according to claim 7 wherein said positive displacement pump is a piston and cylinder type pump. 9. A pressure testing and calibrating apparatus according to anyone of the preceding claims wherein said means to release the raised pressure is a valve. 10. A pressure testing and calibrating apparatus according to claim 7 wherein said means to ascertain the pressure within said vessel is a capillary type pressure gauge. 11. A pressure testing and calibrating apparatus according to claim 10 wherein said gauge is integeral with said hatch. 12. A pressure testing and calibrating apparatus substantially as herein described with reference to the accompanying drawing.

Inventors: BRECKELL GREGORY JOSEPH, SANDS ROBERT LYNE, BRECKELL, GREGORY, JOSEPH, SANDS, ROBERT, LYNE
Applicants: BRECKELL GREGORY JOSEPH, SANDS ROBERT LYNE, BRECKELL, GREGORY, JOSEPH, SANDS, ROBERT, LYNE
Application year: 1985
Main classification: G01L27
IPC codes: G01L27