Hale Q Series Muscle - Manual (Page 48)

 Accessories / Options
48 MUSCLE (Midship) Pumps Installation, Operation, and Maintenance Manual
p/n: 029-0020-63-0
Figure 3-14: Hale (TPM) Total Pressure Master Relief Valve System
The TPM relief valve system automatically relieves excess pump pressure when oper-
ating from draft or positive incoming flows. The system self-restores to the non-reliev-
ing position when excessive pressure is no longer present. The PMD control permits
the pump operator to “set” a desired pressure for both internal and external relief
valves. The panel control has an easy-to-read and easy-to-set adjustment with an
approximate pressure setting indication.
How the TPM Works
The TPM system monitors and controls pump pressure and relieves excessive pres-
sure by first utilizing the internal relief valve (QG), thus returning flow to the pump suc-
tion.
If excessive pressure remains and there is positive pressure on the suction, a second-
ary external relief valve (PG30) responds by discharging excessive pressure to the
atmosphere.
The staging of the internal and external relief valves to operate in series ensures max-
imum protection against over pressure and eliminates the indiscriminate discharging
of water to the ground.
The external relief valve (PG30) is mounted on the discharge side of the pump. Dis-
charged water flowing through the valve provides a self-cleaning process and nearly