Data Sheet

ManualsBrandsEmerson ManualsOtherCS800

Bulletin 71.1:CS800

travel of the relief seat. Since the diaphragm continues

to rise as downstream pressure builds, the diaphragm

lifts off of the relief seat to provide relief operation. The

secondary travel stop for internal relief is not available

on token relieving units. Units with high capacity

internal relief valve have 2-1/2 NPT vent size. See

Figures 10, 12, 14, 16, 18 and 20 for relief capacity.

Token Relief “T” and Low Flow Token

Relief “L”

Type numbers with the “T” or “L” sufx, e.g.,

Types CS800IT and CS800IL provide a low capacity/

token relief. Token relief provides relief from minor

overpressure caused by nicks or dents on the orice

or by thermal expansion of gas in the downstream line.

Token relief also provides a token or signal, in the form

of odor, that an overpressure situation is occurring.

Start-to-discharge values for Token reliefs are found

in Table 5. Maximum discharge capacities for Token

reliefs are found in Figure 8.

Types CS803 and CS823 Integral

True-Monitor™ Operation

Types CS803 and CS823 combine the operation of a

conventional two-regulator wide-open monitor set into

one body, see Figure 5. The Integral True-Monitor is

installed on the inlet side of the body and serves to

control downstream pressure in the situation where the

Primary regulator can no longer regulate downstream

pressure. During normal operation the True-Monitor is

in a wide-open state as its setpoint is set higher than

the primary regulator. See Tables 7 and 8 for guidance

regarding the setpoints of the regulator and associated

Integral Monitor sets. If the downstream pressure

should rise to the setpoint of the True-Monitor due to

loss of pressure control by the primary regulator, the

monitor will assume control and regulate ow to the

downstream system. Internal and external downstream

pressure registration are available. External pressure

registration requires a downstream sensing line. See

the Type TM600 Instruction Manual for additional

details of operation.

If a Token relief is present, the token relief will relieve

a small amount of gas to the atmosphere as an

indication that the Integral Monitor is controlling the

downstream pressure.

Types CS804, CS824 and CS854

Slam-Shut Operation

The Type VSX8 Slam-shut module on the

CS804 Series regulators is a fast acting shutoff

device that provides overpressure (OPSO) or

overpressure and underpressure (OPSO/UPSO)

protection by completely shutting off the ow of gas

to the downstream system. See Tables 12 and 13

for guidance regarding the typical setpoint of the

regulator and associated OPSO and UPSO sets.

The Type VSX8’s actions are independent of the

CS804 Series regulator and of variations to the inlet

pressure. The Type VSX8 provides the option of

internal or external downstream pressure registration.

External registration requires a downstream

sensing line.

The Type VSX8 shutoff disk is normally in the open

(reset) position, see Figure 6. If the downstream

pressure below the slam-shut diaphragm increases (or

decreases) until it reaches the slam-shut setpoint, this

diaphragm moves upward (or downward) to release

the trip mechanism which allows the spring force on

the stem to push the disk against the seat, shutting

off all gas ow. To reset the slam-shut after gas has

been shutoff, refer to Type VSX8 Instruction Manual

(D103127X012) for additional details.

Figure 8. Maximum Discharge Capacity for Token and Low Flow Token Relief

REGULATOR SETPOINT, psig / bar

Discharge Capacity in SCFH / Nm

/h at Maximum Operating Outlet

(3 psi / 0.21 bar setpoint) (Specific Gravity Gas = 0.6)

6 / 0.41

150 /

4.02

200 /

5.36

250 /

6.7

300 /

8.04

350 /

9.38

400 /

10.72

450 /

12.06

5.5 / 0.38

4.5 / 0.31

2.5 / 0.17

3.5 / 0.24

1.5 / 0.10

0.5 / 0.03

5 / 0.34

4 / 0.28

3 / 0.21

2 / 0.14

1 / 0.69

REGULATOR SETPOINT, psig / bar

Discharge Capacity in SCFH / Nm

/h at Maximum Operating Outlet

(3 psi / 0.21 bar setpoint) (Specific Gravity Gas = 0.6)

6 / 0.41

8 /

0.214

10 /

0.268

12 /

0.322

14 /

0.375

16 /

0.429

20 /

0.536

22 /

0.59

24 /

0.643

18 /

0.482

26 /

0.697