MKS HPS LPV1-25-AC Series, Operation And Maintenance Manual

Page: 32 / 52

24
HPS HPS
HPS HPS
HPS
®
Square Body LoPro Square Body LoPro
Square Body LoPro Square Body LoPro
Square Body LoPro
Seri es Seri es
Seri es Seri es Seri es
24
7.2.3 Actuator Assembly Installation
Insert the actuator assembly into the valve body. As with removal, take care
to avoid damaging the bellows. Be sure that the bonnet o-ring is in place.
The bellows flange is appropriately tapered to aid in retaining the o-ring in
the proper position during assembly.
Before bolting the actuator to the valve body, make sure the pneumatic port
is located in the desired orientation. Insert the four bolts and tighten the
actuator to the valve body. The actuator assembly is completely installed
when the bottom of the actuator is flush to the top of the valve body and the
four attaching bolts are tightened to 45-50 in. lb. (» 5.0 Nm).
Reconnect the pneumatic supply and electrical connections (if applicable).
Refer to section 7.4 for details on limit switch assembly.
It is highly recommended to check the assembly for leaks using a high
quality Helium mass spectrometer leak detector. The vent slot in-
between the actuator cap and the bonnet flage is used for leak detection.
With the interior of the valve evacuated and attached to the He mass
spectrometer, insert the tracer gas probe into this slot. If a leak is
detected, either the bellows or the bonnet seal is faulty. The nosepiece
seal and port flange seals may be tested through a variety of methods
and will not be detailed here.
7.3 Actuator Assembly – Manual Version
7.3.1 Actuator Assembly Removal and Disassembly
The following procedure does not require removal of the valve body
from the system. However, several aspects of the procedure are
more easily performed if the entire valve is removed. Read section
7.1.2 prior to removing the entire valve or a valve’s actuator
assembly from a vacuum system.
The actuator assembly is attached to the bonnet of the valve by four bolts.
To remove the actuator assembly, simply loosen and remove these four
bolts. After the bolts are removed, pull the actuator assembly out of the
valve body. The bellows is fabricated of .006" thick 321 stainless steel.
While withdrawing the actuator assembly, exercise care to avoid damaging
the bellows. If the bonnet o-ring has adhered to the sealing surface in the
body carefully remove it by hand. If a tool is required for this task, it should
be made of a material softer than stainless steel to avoid scratching the
sealing surface.
Replacement of malfunctioning actuators with new assemblies is
recommended (see parts list section 7.6 for details).