Table des Matières
Publicité
Les langues disponibles
Les langues disponibles
Installation - Operation - Maintenance
DESCRIPTION
The CRD Pressure Reducing Control automatically reduces a higher
inlet pressure to a lower outlet pressure. It is a direct acting, spring
loaded, diaphragm type control that operates hydraulically or pneumati-
cally. It may be used as a self-contained valve or as a pilot control for a
CLA-VAL main valve. It will hold a constant downstream pressure within
very close pressure limits.
OPERATION
The CRD Pressure Reducing Control is normally held open by the force
of the compression spring above the diaphragm; and delivery pressure
acts on the underside of the diaphragm. Flow through the valve respon-
ds to changes in downstream demand to maintain a pressure.
INSTALLATION
The CRD Pressure Reducing Control may be installed in any position.
There is one inlet port and two outlets, for either straight or angle instal-
lation. The second outlet port can be used for a gage connection. A flow
arrow is marked on the body casting.
ADJUSTMENT PROCEDURE
The CRD Pressure Reducing Control can be adjusted to provide a
delivery pressure range as specified on the nameplate. Pressure
adjustment is made by turning the adjustment screw to vary the spring
pressure on the diaphragm. The greater the compression on the spring
the higher the pressure setting.
1.
Turn the adjustment screw in (clockwise) to increase delivery
pressure.
2.
Turn the adjustment screw out (counter-clockwise) to decrease
the delivery pressure.
3.
When pressure adjustment is completed tighten jam nut
4.
on adjusting screw and replace protective cap.
5.
When this control is used, as a pilot control on a CLA-VAL main
valve, the adjustment should be made under flowing conditions.
The flow rate is not critical, but generally should be somewhat
lower than normal in order to provide an inlet pressure several
psi higher than the desired setting.
The approximate minimum flow rates given in the table are for the
main valve on which the CRD is installed.
Valve Size
1 1/4" -3"
Minimum
0,95 - 1,9
Flow l/s
MAINTENANCE
DISASSEMBLY
To disassemble follow the sequence of the item numbers assigned to
parts in the sectional illustration (CRD001TT).
REASSEMBLY
Reassembly is the reverse of disassembly. Caution must be taken to
avoid having the yoke (17) drag on the inlet nozzle of the body (18).
4"-8"
10"-16"
3,15 - 12,6
19,0 - 41,0
Pressure Reducing Control
Follow this procedure:
1.
Place yoke (17) in body and screw the disc retainer assembly (16)
until it bottoms.
2.
Install gasket (14) and spring (19) for 2-30 and 2-6.5 psi range
onto plug (13) and fasten into body. Disc retainer must enter guide
hole in plug as it is assembled. Screw the plug in by hand. Use
wrench to tighten only.
3.
Place diaphragm (12) diaphragm washer (11) and Belleville wa-
sher (20) on yoke. Screw on hex nut (10).
4.
Hold the diaphragm so that the screw holes in the diaphragm
and body align. Tighten diaphragm nut with a wrench. At the fi-
nal tightening release the diaphragm and permit it to rotate 5° to
10°. The diaphragm holes should now be properly aligned with the
body holes.
To check for proper alignment proceed as follows:
Rotate diaphragm clockwise and counter clockwise as far as possible.
Diaphragm screw holes should rotate equal distance on either side of
body screw holes ±1/8".
Repeat assembly procedure until diaphragm and yoke are properly
aligned. There must be no contact between yoke and body nozzle du-
ring its normal movement. To simulate this movement hold body and
diaphragm holes aligned. Move yoke to open and closed positions.
There must be no evidence of contact or dragging.
5.
Install spring (9) with spring guide (8).
6.
Install cover (5), adjusting screw (2) and nut (3), then cap (1).
SYMPTOM
PROBABLE CAUSE
No spring compression Tighten adjusting screw
Damaged spring
Fails to open
when deliver
Spring guide (8) is not
pressure
in place
lowers
Yoke dragging on inlet
nozzle
Spring compressed
solid
Mechanicalobstruction
Fails to close
when delivery
pressurerises
Worn disc
Yoke dragging on inlet
nozzle
Damaged diaphragm
Leakagefrom
cover vent
hole
Loose diaphragm nut
42
Serie 578
REMEDY
Disassemble and
replace
Assemble properly
Disassemble and
reassemble properly
(refer to Reassembly)
Back off adjusting screw
Disassemble and
reassemble properly
(refer to Reassembly)
Disassemble remove
and replace disc retainer
assembly
Disassemble and
reassemble properly
(refer to Reassembly)
Disassemble and
replace
Remove cover and
tighten nut
Publicité
Table des Matières
