Leslie Controls GP Pressure reducing valve User Manual
Page 3
Page 3
SECTION II — OPERATION
For installation, adjustment of loading device and operating
details, consult the proper instructions pertaining to the par-
ticular type of loading, sensing or other operating device.
Overall Valve Dimensions
For overall valve dimensions — face-to-face, height, etc., —
consult the drawing which applies to the valve in use.
Principle of Operation
The control valves are operated by means of an airloading
force delivered by a loading valve, temperature pilot or similar
device which delivers an air signal to the diaphragm of the
regulator. Figure 3 shows the loading pressures required for
various valve sizes and pressure drops. Diaphragm pressure
quoted, for any particular size or pressure drop, is the pres-
sure required on the diaphragm to open the valve under the
existing conditions. Beyond this value an ratio of 1:1 delivered
steam pressure to additional air loading pressure will be
obtained. The valve will them maintain the controlled pres-
sure accurately and in direct relation to the loading pressure
value above that which is necessary to open the valve.
Operation of GP Type Control Valves
In conjunction With Air Loaders
Important: DO NOT apply air-loading force to diaphragm of
control valve until inlet stop valve is fully opened with full pres-
sure to inlet of the control valve.
Starting Up:
1.
Open inlet stop valve.
2.
Close outlet stop valve.
3.
Dispose of condensation, dirt, etc., by opening the
strainer blow-off valve.
4.
Crack outlet stop valve to permit slight flow when
adjusting the control valve.
5.
Slowly supply loading pressure to control valve
diaphragm until the valve begins to open. Gradually
increase loading pressure until desired downsteam
controlled pressure is obtained.
6.
Slowly open outlet stop valve.
7.
To increase controlled pressure, increase loading pres-
sure. To decrease controlled pressure, decrease load-
ing pressure.
Shutting down:
To turn steam off, relieve loading pressure from diaphragm of
the control valve and close inlet and outlet stop valves.