CHAPTER 7
REPAIR OF REGULATORS
7-1. General.
The regulators are spring-loaded diaphragm type
(Fig. 7-l). Regulator pressure is adjusted by in-
creasing or decreasing the pressure on spring (9)
above the diaphragm (8) with adjusting handle (11)
through the top of cover (13). Increasing spring
pressure increases regulated pressure. Direction of
air flow is indicated by an arrow on body (7) near
the inlet side of the regulator. Air enters the inlet
on the arrow marked side and flows past a valve (4),
which is held open by diaphragm (8), through the
body (7) and leaves the outlet side. If air pressure in
the body (7) is more than the force of the spring on
the diaphragm, the diaphragm is forced up which,
in turn, allows valve (4) to follow and close against
a seat in the body (7). As air is used from outlet side,
body pressure drops, letting diaphragm force valve
(4) away from seat allowing more air into the body
(7). Thus, outlet pressure is held constant.
7-2. Procedure.
a. Disassemble regulator using Figure 7-1 as a
guide. Proceed as follows:
NOTE
Regulators can be disassembled in
place on the paint tank. Leave body (7)
piped to tank head.
(1) Unscrew bottom plug (1) from body (7). O-
Ring (2), spring (3) and valve (4) will all be free and
come out of body (7) when bottom plug (1) is re-
moved.
(2) Unscrew four screws (6) and lift cover (13)
from body (7). Diaphragm (8), spring (9) and disc
(10) are now free and can be lifted from body (7).
(3) Remove adjusting screw (11) and nut (12)
from cover (13).
NOTE
It is not necessary to remove pipe plug
(5) from body (7).
b. Clean all parts with a petroleum based solvent
such as kerosene or diesel fuel.
c. Check all parts for damage or undue wear. Use
only serviceable parts when assembling regulator.
d. Assemble regulator using Figure 7-1 as a
guide, proceed as follows:
(1) Screw nut (12) onto adjusting handle (11)
and screw adjusting handle (11) into cover (13).
(2) Align diaphragm (8) over body (7) so holes
line up. Place spring (9) on center of diaphragm (8)
and disc (10) in center of spring (9). Place cover (13)
over diaphragm (8) so holes line up. Insert four
screws (6) into cover (13) holes and screw down
tight.
{3) Place O-Ring (2) over threads on bottom
plug (l), and insert valve (4) into center of spring
(3). Carefully insert all four parts (1,2,3, &4) into
body (7) and screw bottom plug (1) by hand until
tight.
e. Regulator should now be installed on the pres-
sure tank and checked for proper operation. With an
air inlet pressure of from 65 to 80 psi, turn adjust-
ing screw (11) until pressure gage reads 40 psi.
Monitor pressure gage for two to three minutes,
pressure should remain constant. If not, look for a
regulator assembly error.
7-1
TM 5-4940-228-14
