Masoneilan 74000 Series Control Valves Instructions Manual | 3
Copyright 2021 Baker Hughes Company. All rights reserved.
Unpacking
Care must be exercised when unpacking the valve to prevent
damage to the accessories and component parts. Contact the
local Baker Hughes Sales Office or Aftermarket Center with any
issues or problems. Be sure to note the valve model number and
serial number in all correspondence.
Installation
The 74000 Series control valve must always be
installed with the flow tending to close the valve plug.
For applications where insulation of the valve body is
required, do not insulate the valve bonnet.
Piping Cleanliness
Before installing the valve in the line, clean piping and valve of all
foreign material such as welding chips, scale, oil, grease or dirt.
Gasket mating surfaces must be thoroughly cleaned to ensure
leak-free joints. Sacrificial start-up fixtures can be purchased
from Baker Hughes to protect the operational trim during the
installation and line flushing phases.
If major system or piping modifications (or repairs)
are performed, thorough flushing and blowdown of
the system will be required prior to reinstalling the
74000 Series trim. Sacrificial flushing trim should
be installed in this valve to protect the integrity of
the flow passages. Failure to follow this warning will
violate the valve warranty agreement and could result
in control instability, excessive noise levels, and valve
leakage.
Isolation Bypass Valve
To allow for in-line inspection, maintenance and removal of the
valve without service interruption, provide a manually operated
shutoff valve on each side of the control valve and a manually
operated throttling valve in the bypass line.
Heat Insulation
When wrapping this valve with heat insulation, note that the 74000
Series is a bottom entry valve requiring unique considerations.
To allow for maintenance, the insulation configuration should
allow for removal of valve body from the line and separation of
the upper and lower body components at the flange joint. Also
note that the packing box is integral to the upper body and should
not be externally insulated so that this region does not retain
excessive heat.
Hydrostatic Testing and Line
Cleaning
During this operation, the control valve must not be used as an
isolating valve. This means that the valve must always be opened
before carrying out pressure tests in the process line, cleaning of
pipes, etc. Otherwise equipment damage or failure of the seal
rings could result. Flushing and hydrostatic test equipment can
be purchased from the Baker Hughes factory.
Flow Direction
The valve must be installed so that the process fluid will flow
through the valve in the direction indicated by the flow arrow
located on the body.
Welded Connections
Carefully review the information in this section prior
to welding any valves inline. Refer any additional
questions to the local Baker Hughes Sales Office or
Service Center.
Pre-Weld Preparation
Carefully follow the installation steps defined in the sections
noted above prior to performing weld procedures.
Welding Process
Perform welding process in accordance with the standard
requirements for the materials and weld construction of the
specific valve. Apply post weld heat treatment if required.
Internal valve components should be removed prior
to performing any post weld heat treatment in order to
prevent damage. If unable to remove the elastomeric
components, then other methods must be employed
to prevent the local temperature around the seals
from exceeding the maximum material limits (typically
450°F/232°C for PTFE-based materials).
Post Weld Cleaning & Assembly
Inspect the body, bonnet, and trim components for cleanliness
and surface condition. Remove any foreign materials, such as
weld chips, slag or scale. Make sure there are no nicks, scratches,
burrs or sharp corners on sealing and sliding surfaces. Clean all
gasket interface surfaces and reassemble using new gaskets to
ensure sealing integrity.
