CVS Controls 667 Instruction Manual - Page 3

Browse online or download pdf Instruction Manual for Controller CVS Controls 667. CVS Controls 667 8 pages. Diaphragm actuator

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AIR

LIFTS

STEM UP

Figure 2: Schematic of CVS Type 667 Actuator

Loading Connection cont'd

5. If the valve stem travel or pressure range is

incorrect, refer to the "Adjustments" section of

this manual.

Do not place the valve in service if it is not

responding properly to diaphragm loading pressure

changes.

For ease of service, ensure that the control valve is

located for easy access and serviceability with room

above for accessibility. Ensure that sufficient room is

provided below should removal of the actuator and

valve plug be necessary.

Adjustments

Travel

Refer to the nameplate on the yoke of the actuator

for details on the specific construction and operating

range of the control valve assembly.

The requirements of your specific application will

dictate the spring and diaphragm used in your CVS

Type 667 Actuator, and when in service, the actuator

should create full travel of the valve plug when

diaphragm pressure is applied according to the

range indicated on the name plate. Generally, the

diaphragm pressure range is 3 to 15 PSI or 6 to 30

PSI, but other ranges may be used.

If the motion during the actuator travel differs from

the travel stamped on the actuator nameplate, adjust

according to the following directions. In order to

adjust the travel of a direct-acting valve, slightly

pressure the actuator to move the valve plug off of

the seat. This reduces the chance of damaging the

valve plug or seat during adjustments.

SPRING

PUSHES

DOWN

STEM SEAL

STEM

1. Loosen and back off the stem locknuts and

indicator disc from the stem connector.

2. Loosen the stem connector cap screws.

Note: Do not use wrenches or other tools

directly on the valve stem as this could cause

damage to the stem surface and valve packing.

3. Tighten the locknuts (Keys 14 and 20) and

complete the adjustment by either screwing the

valve stem into the stem connector to lengthen

travel or out of the stem connector to shorten

travel.

4. Cycle the actuator to ensure that the correct

travel has been achieved and repeat the

adjustment if necessary.

5. When the correct travel has been reached

tighten the stem connector cap screws.

6. Raise the travel indicator disc by threading the

stem locknuts against the stem connector.

7. Adjust the travel scale to match the disc.

Spring

If the loading pressure range applied to reach the

desired travel differs from that specified on the

nameplate, a spring adjustment is required.

Check the "Bench Set" pressure range on the

nameplate when the valve contains no pressure and

the packing is loosely inserted in the bonnet. Refer

to the "Diaphragm Pressure" range on the nameplate

when the valve is controlling the specified pressure

drop and the packing is tightened to stop leaks

around the stem.

1. Monitor the loading pressure while making

adjustments. Be sure not to exceed the

pressure specifications of either the loading

regulator or the actuator casings.

2. Each actuator spring has a fixed pressure span.

Changing the spring compression shifts the span

up or down to make the valve travel coincide

with the loading pressure range.

Figure 3: Nameplate on CVS Type 667 Actuator