Emerson A31A Manual de instrucciones descargar pdf (Pagina 3)

Cryogenic-Rotary Valve

Instruction Manual

Form 5482

February 2005

at the beginning of the Maintenance

section in this instruction manual.

CAUTION

Responsibility for the safety of

process media and compatibility of

valve materials rests solely with the

purchaser and end-user. When

ordered, the valve configuration and

construction materials were selected

to meet particular pressure, pressure

drop, temperature, and controlled fluid

conditions. Because pressure drop

and temperature range capabilities

limit some combinations of materials,

do not apply any other conditions to

the valves without first contacting your

Fisher sales office.

Before installation check the maximum allowable

inlet pressures for Type A31A Cryogenic valves

shown in figure 2 and the Specifications table.

Adjusting the Actuator Travel Stops

WARNING

The edges of a rotating valve disc have

a shearing effect that may result in

personal injury. To avoid personal

injury, keep clear of the disc edges

when rotating the disc.

CAUTION

When using an actuator, the actuator

travel stops or the actuator travel (for

actuators without adjustable stops)

must be adjusted so that the disc stop

in the valve body does not absorb the

output of the actuator. Failure to limit

actuator travel as described in the next

step can result in damage to the valve

shaft or other valve parts.

1. Locate the actuator travel stop that establishes

the closed position of the valve disc. When adjusting

the travel stop or travel, make sure that the disc is

from 0.03 to 0.76 mm (0.001 to 0.030 inch) away

from the internal stop in the valve body. This

adjustment is necessary to be certain that the

actuator output torque is fully absorbed by the

actuator travel stop or by the actuator. The internal

travel stop in the valve body should not absorb any

of the actuator torque.

2. Before installing the valve/actuator assembly in

the process line, cycle the valve several times to be

sure the valve disc returns to the proper position.

Valve Orientation

Note

When the process flow is gas, install

the valve with the shaft in the

horizontal position.

When the process flow is liquid the

valve should be installed at an incline

above horizontal of at least 20

degrees, as shown in figure 3. Inclined

installation can enhance valve

performance by preventing direct

cryogenic liquid contact with the

packing.

The Type A31A Cryogenic valve is designed for

installation with the shaft(s) in any orientation around

the pipeline: horizontal, vertical, or at an

intermediate angle. However, when installing the

valve in cryogenic service, follow the

recommendations below, which are based on

application experience:

D Installing the valve with the extension housing

or bonnet four to six inches beyond the cold box

(see figure 3) provides space for slight boil-off of

cryogenic liquids.

D When installed with the extension stem inclined

20 degrees above horizontal, the vapor pocket

resulting from cryogenic liquid boil-off prevents the

colder liquid from contacting the stem packing area.

D Recommended installation for optimum seal

performance of the NOVEX and Kel-F seals is

reverse flow (into the back of the disc).

D A flow tag with an arrow is provided for proper

installation.

1 2 3 4 5 6 7 8 ... 23 24

Comentarios a estos manuales

Sin comentarios

Emerson A31A Manual de instrucciones Pagina 3

Comentarios a estos manuales

Relacionado con productos y manuales para Motor accesorios y componentes de vehículos Emerson A31A