TM 55-1930-209-14&P-3
4-7.1.4
Chemical metering pump check valves cleaning. Check valves are located in the foot valve, suction inlet
on dosing head, pressure outlet on dosing head, and injection valve on the process stream. These valves are all the
same and are disassembled for cleaning as follows:
NOTE
The following procedures are the same for both chemical metering pumps.
a.
Remove chemical metering pump according to paragraph 4-8.1.1.
b.
Once pump is removed, disassemble dosing head (Figure 4-2) as follows:
(1)
Remove four screws and flatwashers holding dosing head to pump. Remove dosing head, diaphragm,
and disc head.
(2) Set pump stroke length knob (Figure 3-5) at 0 percent.
(3)
Remove discharge valve body and C-ring. Remove valve ball and -ring.
(4)
Remove suction valve body and O-ring. Remove valve ball and O-ring.
(5)
Remove bleeder valve and O-ring.
(6)
Using small punch, press sleeve, valve ball, and two O-rings from discharge and suction valve bodies.
(7)
Thoroughly wash parts and clean water to remove dry or caked media. Replace any damaged or worn
O-rings or balls.
c.
Reassemble dosing head assembly as follows:
(1)
Install O-ring and valve ball in discharge valve body. Press in O-ring and sleeve.
(2)
Install O-ring on discharge valve body.
(3)
Install valve ball in dosing head. Install O-ring in dosing head. Install discharge valve.
(4)
Install O-ring and valve ball in suction valve body. Align hole in sleeve with hole in body. Press in O-
ring and sleeve.
(5)
Install O-ring in suction valve body.
(6)
Install valve ball and O-ring in dosing head. Install suction valve.
(7)
Install O-ring and bleeder valve in dosing head.
(8)
Set pump stroke length knob at 0 percent.
(9)
Set pump stroke knob at 100 percent.
(10) Rotate head disc down and align screw holes.
(11) Install diaphragm.
(12) Install dosing head with arrow pointing up. Install four screws and flat washers.
d.
Reinstall chemical metering pump in accordance with paragraph 4-8.1.1.
4-13
