Figure 2-1. Back Pressure Valve Test Set-Up
a. Install retainer (12) and packing (11) in
as specified, the inlet pressure, gage No. 1, shall be
groove of piston (9). Install second packing (11) in
groove of piston seat (10).
c. To test for full flow with back pressure,
b. Install piston seat (10) and piston (9) in
adjust the pressure regulator and the shutoff valve until
valve body (13).
the outlet pressure, gage No. 2, is 1700 100 psig and
the flowmeter indicates a flow of 4.0 scfm. With the
outlet pressure as specified the inlet pressure shall not
c. Position tube fitting gaskets (5) in grooves
exceed 1800 psig as indicated at gage No. 1.
of inlet and outlet fittings (3 and 4). Screw fittings into
appropriate ports of valve body (13) and tighten to a
d. Fully open the shutoff valve. Starting with
zero inlet pressure, open the pressure regulator to
d. Place spring (8), flanked by two spring
gradually increase inlet pressure to 1600 psig. With the
plates (7), into valve body (13). Screw valve cap (6)
inlet pressure as specified leakage through the back
into valve body until top surface of cap is approximately
pressure valve shall not exceed 5.0cc/min., as indicated
flush with upper edge of valve body.
by the flowmeter.
TEST AND ADJUSTMENT.
e. With the shutoff valve fully open, adjust
the pressure regulator for inlet. pressure of 1800 psig.
Close pressure regulator to decrease the inlet pressure
a. Install the back pressure valve into the test
to 1600 psig. With the inlet pressure decreased as
specified, leakage through the back pressure valve shall
not exceed 0.15 scfm as indicated by the flowmeter.
b. Open the shut-off valve fully. Open the
pressure regulator to gradually increase inlet pressure
Close the shutoff valve and adjust the
until the flowmeter indicates a flow of 4.0 scfm, to test
for full flow pressure. With the flow