Pressure test gauge

Abstract: A pressure test gauge is described, more particularly for testing the air pressure at the outlet of a spraygun. The pressure test gauge comprises a body (1) having an inlet (2) which may take the form of a replaceable screw in unit (3) sealed airtight with the body (1). The unit (3) encircles the inlet (2) and connects with passages (4, 5) passing through body (1). The passage (5) is a small bore tube which connects inlet (2) with a pressure gauge (6) which has a display (7). Intermediate the inlet unit (3) and gauge (6) is a valve (8) comprising a barrel (9) with an outer screw-thread (10) screwed into body (1); extending axially of valve (8) is a metering hole (11). The gauge body may have ribs (12) to facilitate gripping the body and a bracket (13) with screws (14) to secure it to a wall.

Description: This invention relates to a pressure test gauge more particularly for testing the air pressure at the outlet nozzle of a spraygun. In known sprayguns for spraying paint or other fluids the outlet pressure is required for environmental and operational purposes to be maintained at 10 p.s.i. It is common practice to test the outlet pressure of the air pressure passing through the spraygun using an adapter to connect the spraygun nozzle to a pressure test gauge or to fit a specially adapted test nozzle in place of the one to be used for spraying. The measurement of the air pressure must be the pressure of the air flowing through the nozzle outlet rather than a stationary head of pressure. US-A-3 630 080 describes an electronic pressure gauge incorporated into the wall of a pressure chamber in a paint spray gun. This known practice has the disadvantage that the testing of the nozzle pressure, as may be required before using the spraygun or during use, is a complex and often messy process in fitting an adapter to a nozzle coated in paint. According to the present invention there is provided a pressure test gauge comprising a body having an inlet with means to seal the inlet to the source of air pressure to be tested, a gauge connected to the inlet, and a valve connected between the inlet and gauge to the outside of the body wherein a separate passage is connected between the inlet and the gauge. Conveniently, the valve comprises a screw-threaded barrel with an axial metering hole. In a preferred construction the gauge has a digital display. An embodiment of an air pressure test gauge will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a pressure test gauge according to the present invention; Figure 2 is a longitudinal cross-section taken along the line II-II of Figure 1. Figure 3 is an end view of the test gauge shown in Figures 1 and 2; Figure 4 is a side elevation of a modified construction of the test gauge; and Figure 5 is an end view of Figure 4. The pressure test gauge comprises a body 1 having an inlet 2 which may take the form of a replaceable screw in unit 3 sealed air-tight with the body 1. The unit 3 encircles the inlet 2 and connects with passages 4 and 5 passing through the body 1. The passage 5 is a small bore tube which connects the inlet 2 with a pressure gauge 6 which may have a digital or analogue display 7. Intermediate the inlet unit 3 and the gauge 6 is a valve 8 comprising a barrel 9 with an outer screw-thread 10 to screw the valve into the body 1. Extending axially of the valve is a metering hole 11. The pressure test gauge has a series of ribs 12 to facilitate the gauge to be held and applied in the hand when in use, or the gauge body 1 may be mounted on a surface, e.g. a wall, adjacent the location of use. In the example illustrated the body may be connected via bracket 13 with screws 14 to secure it to a wall (not shown). The spraygun can readily be checked for the correct outlet pressure by pushing the spraygun nozzle 15 (shown in chain-dotted line) against the pressure test gauge inlet 2. In operation, the unit 3 is selected to fit the front profile of the appropriate spraygun nozzle 15 and is then screwed into the pressure test gauge body 1. The valve 8 is selected to match the air flow characteristics of the spraygun nozzle in use and is screwed into the gauge body 1. Thus the air is allowed to flow while in the passage 4 while air is passed through the small bore tube to test the air pressure by the gauge 6. A modified test gauge construction is illustrated in Figures 4 and 5 in which like parts have the same reference numerals as in Figures 1 and 2. This gauge is modified for use in testing static pressure of subsidiary functions of equipment associated with spray guns. The inlet 2 to the gauge is closed by a blanking plug 16 and the valve 8 is replaced by an appropriate quick release connector 17 so that the air pressure passes via the tube 18 into the passage 4 encircling the tube 5 and passes via the recess 19 in the blanking plug 16 along the tube 5 to the gauge 6 to be tested.

Claims: A pressure test gauge comprising a body (1) having an inlet (2) with means (3) to seal the inlet (2) to the source of air pressure to be tested, a first passage (4,11) connecting the inlet (2) to the outside of the body (1) through a valve (8), and a pressure gauge (6), characterised in that said pressure gauge (6) is connected to said inlet (2) by a separate passage (5) which extends through that part of said first passage (4) connected to the inlet (2). A gauge as claimed in Claim 1, characterised in that the means (3) to seal the inlet (2) to the source of air pressure is a replaceable unit sealed in an air-tight manner to the gauge body (1). A gauge as claimed in Claims 1 or 2, characterised in that the separate passage (5) is a small bore tube which is surrounded by an annular passage (4) between the inlet (2) and a passage (11) through the valve (8) to the outside of the body (1). A gauge as claimed in Claim 3, characterised in that the passage (11) through the valve (8) is an axial hole. A gauge as claimed in any preceding claim, characterised in that the gauge (6) has a digital display (7). A gauge as claimed in any of Claims 1 to 3, characterised in tbat the gauge (6) has an analogue display (7). A gauge as claimed in any preceding claim, characterised in that the body (1) has means (13, 14) to secure it to a surface. A gauge, as claimed in Claim 7, characterised in that the securing means comprise a bracket (13) with one of more holes for a screw (14) or screws (14). A gauge as claimed in Claim 1, characterised in that the valve (8) is screwed with a quick release connector to the gauge body (1) to enable the gauge (6) to be used for static pressure measurements of subsidiary functions of spray equipment associated with a spraygun. A gauge as claimed in Claim 2 or 9, characterised in that the means (3) to seal the inlet is blanked off by a blanking plug (16) and the valve (8) is replaced by a quick release connector (17).

Inventors: GUTTORIELLO ANGELO, PETTIT NEVILLE THOMAS, SMITH ROWLAND CHARLES, GUTTORIELLO, ANGELO, PETTIT, NEVILLE THOMAS, SMITH, ROWLAND CHARLES
Applicants: ITW LTD, ITW LIMITED
Application year: 1993
Main classification: G01L19
IPC codes: G01L19