Cashco DL - Manual (Page 2)

IOM-D/DL 2
10.B. Model D Cryogenic Regulator - Option D-5 or D-36
(Refer to Figure 4):
SECTION III
III. PRINCIPLE OF OPERATION
1. Movement occurs as pressure variations register on
the diaphragm. The registering pressure is the out-
let, P
2
, or downstream pressure. The range spring
or loading pressure (Opt.-20) op pos es di a phragm
movement. As outlet pressure drops, the range
spring or loading pressure pushes the dia phragm
down, opening the port; as outlet pres sure in creas-
es, the diaphragm push es up and the port opening
closes.
2. A complete diaphragm failure will cause the reg u la-
tor to fail open.
1. Start with the block valves closed. A bypass valve
may be used to maintain outlet pres sure in the
downstream sys tem without chang ing the fol low ing
steps.
2. Relax the range spring by turning the ad just ing screw
counter clockwise (CCW) a min i mum of three (3) full
revolutions or reduce loading pressure (Opt.-20).
This re duc es the outlet (down stream) pres sure set
point.
3. If it is a “hot” piping system, and equipped with a
bypass valve, slowly open the bypass valve to pre-
heat the system piping and to allow slow ex pan sion
of the piping. Ensure proper steam trap operation
if installed. Close ly monitor outlet (down stream)
pres sure via gauge to en sure not over-pres sur iz ing.
NOTE: If no bypass valve is installed, extra caution
should be used in start ing up a cold system; i.e. do
ev ery thing slow ly.
4. Crack open the outlet (downstream) block valve.
5. Slowly open the inlet (upstream) block valve ob-
serv ing the outlet (downstream) pressure gauge.
Determine if the reg u la tor is fl owing. If not, slowly
rotate the regulator adjusting screw (6) clock wise
(CW) or increase loading pressure (Opt.-20) until
fl ow begins.
SECTION IV
IV. STARTUP
6. Continue to slowly open the inlet (upstream) block
valve until fully open.
7. Continue to slowly open the outlet (downstream)
block valve, especially when the downstream pip ing
system isn't pressurized. If the outlet (down stream)
pressure exceeds the desired pres sure, close the
block valve and go to Step 2, then return to Step
4.
8. When fl ow is established steady enough that the
outlet (downstream) block valve is fully open, begin
to slowly close the bypass valve if installed.
9. Develop system fl ow to a level near its expected
normal rate, and reset the regulator set point by turn-
ing the adjusting screw (6) CW to increase outlet
pressure, or CCW to reduce outlet pressure.
10. Reduce system fl ow to a minimum level and ob serve
set point. Outlet pressure will rise from the set point
of Step 9. The maximum rise in outlet pressure on
decreasing fl ow should not exceed the stated upper
limit of the range spring by greater than 10%; i.e. 10-
40 psig (.69 - 2.8 Barg) range spring, at low fl ow the
outlet pres sure should not exceed 44 psig (3 Barg),
if it does, consult factory.
a. Recommended installation is with spring cham-
ber hang ing directly below the body in a vertical
down wards ori en ta tion. Al lows water to drain;
i.e. rainwater, et cet era.
b. Recommend inert purge gas to spring cham ber
thru vent hole and out drain hole.
11. Regulators are not to be di rect bur ied under-
ground.
12. For insulated piping systems, rec om men da tion is to
not insulate regulator.
13. Spring Chamber Vent Tap - Option D-25 or DL-
25: Pipe spring chamber vent opening to remote
lo ca tion. Orient so as not to take on rainwater.
CAUTION
DO NOT HYDROSTATIC TEST THRU AN IN STALLED
UNIT; ISOLATE REGU LA TOR FROM TEST. The
upper range spring pressure level listed on the
nameplate or 100 psig (6.9 Barg) minimum is the
rec om mend ed “upper op era tive lim it” for the sens-
ing dia phragm (see Sec tion IV. Startup, Num ber 7.)
Higher pres sures could cause in ter nal dam age. In
addition, note on the name plate that the Inlet and
Outlet pres sure and tem pera ture ratings are at dif-
fer ent levels.