DeZurik 250 Manuale di istruzioni - Pagina 4

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DeZURIK

DeZURIK MODELS 145 AND 250 DIAPHRAGM ACTUATOR ISO MOUNTING

Description

The DeZURIK Model 145 or 250 Diaphragm Actuator is a pneumatic rack-and-gear spring-return rotary

actuator used for on-off or modulating control. The actuator is used on a quarter-turn valve with an ISO

actuator mounting configuration. The Model number-145 or 250-is the actuator size, and designates

the effective pressure area in square inches of the spring-loaded diaphragm. The spring action may be

spring-to-close or spring-to-open, and is reversible without additional parts. A choice of three spring

ranges is available-20, 35 or 60 PSI (140, 240 or 420 kPa).

One pneumatic signal line connection is required to the ½" NPT port on the end of the actuator. The

pneumatic signal pressure must equal – but not exceed by more than 10 PSI (70 kPa)-the spring rating

of zero to 20, 35 or 60 PSI (140, 240 or 420 kPa) as shown on the actuator label.

For high vibration installations, additional mounting support is recommended on the spring end of the

actuator to prevent damage to the actuator and/or the piping system. Mount the support from the

pipeline to the end of the spring cartridge.

The actuator is powered pneumatically, and rotates 90 degrees between the open and closed positions.

The action of the actuator is either spring-to-close or spring-to-open, as determined by the orientation of

the diaphragm and the spring cartridge, as shown in Figure 1. The action selected is shown on the

actuator label. With spring-to-close, increasing signal pressure to the actuator opens the valve, and

decreasing pressure closes the valve; with spring-to-open, increasing pressure closes the valve, and

decreasing pressure opens the valve.

The actuator is lubricated at the factory and does not require routine maintenance.

The open and closed position stops are the two hex head cap screws (B23) shown in Figure 1. The

stops are adjustable and prevent the actuator from rotating beyond the open and closed positions of the

valve. If the actuator is factory-mounted on the valve the stops are preset and do not require further

adjustment. If the actuator is not mounted on the valve or if the actuator is removed and/or

disassembled, the stops will require adjustment as described below. Refer to the Valve Instructions for

the closed position requirements and adjust the stops with the actuator mounted on the valve. Refer to

Figure 1 for component identification.

For closed stop adjustment on spring-to-close actuators or open stop adjustment on spring-to-open

actuators:

1. Relieve the air pressure to the actuator.

2. Loosen the jam nut (B24) on the appropriate stop screw (B23). Refer to Figure 1.

3. Turn the stop screw in or out until the valve is in the correct position. The screw will turn easier

if air pressure-just enough to relieve the force on the screw-is applied to the actuator. Relieve

the pressure to check the stop screw adjustment.

4. Hold the stop screw from turning and tighten the jam nut to 230 ± 30 foot founds (312 ± 41 Nm)

if carbon steel or to 140 ± 18 foot pounds (190 ± 24 Nm) if stainless steel.

September 2015

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D10368