Cla-Val 501A Series - Manual

Wafer Swing Check Valve
DESCRIPTION
The Cla-Val Model 501A Wafer Swing Check Valve combines low
head loss characteristics and a compact space saving design. It
is intended for use with a wide variety of fluids including water, oil,
gas, and steam. The 501A Check Valve is designed for installa-
tion between ANSI flanges centered and supported by the flange
bolts.
INSTALLATION
The Cla-Val 501A Check Valve is designed to fit between ANSI
Class 125 and Class 150 Flanges (flat face). Two standard flange
gaskets for each valve are recommended.
Determine minimum bolt/stud length by adding check valve length
to ANSI bolt length. ANSI bolt length can be found in the following
standards: For Class 125 use ASME/AWWA/ANSI standard
B16.1, or For Class 150 use ASME/AWWA/ANSI standard B16.5.
The Cla-Val 501A Check Valve is installed between pipe flanges
with the nameplate or eye bolt on top and with the flow arrow indi-
cating the "free flow" direction. The 501A is intended for horizon-
tal pipe installations, but can operate satisfactorily in vertical up
flow applications. See engineering data sheet E-501A for recom-
mendations.
During flowing conditions the clapper swings into the downstream
piping. To avoid valve damage this piping must be: 1.) full internal
pipe diameter, 2.) without internal mechanical obstructions, and
3.) straight for a minimum of 3 pipe diameters from the valve out-
let.
The valve is supported between the flanges by long flange bolts
and nuts or studs and nuts connecting the two pipe flanges. The
valve is centered to the pipe by the flange bolts. 12 " and larger
size valves are quite heavy, so some form of support is recom-
mended.
Two customer supplied gaskets are needed.
1.) Before valve is installed, pipe line should be flushed of all
chips, scale, and debris.
2.) It is recommended that either gate or block valves be installed
near both ends of the 501A Check valve to facilitate isolating the
valve for preventative maintenance and repair.
3.) Verify flange dimensions match valve rating and dimensions.
4.) Loosely install lower half of the flange bolts with gaskets on
both flanges.
5.) Lower 501A Check Valve between flanges and gaskets with
nameplate or eye bolt upwards and centered until it is resting and
supported by lower bolts. Note flow arrow
orientation to be sure it is correct for the application.
6.) Install remaining upper bolts and tighten in a “cross-over” pat-
tern until no leaks appear.
OPERATION
The standard soft seat provides a drip tight seal and the quick
spring assisted closure minimizes the possibility of water hammer.
The clapper initiates closure before flow reversal to prevent any
surges created by the check valve closure.
MAINTENANCE
Due to the low wearing working parts and simple construction the
501A Check valve will provide many years of trouble free service.
However, for critical applications or for preventative maintenance,
an annual visual inspection is recommended.
The primary symptom that signals the need for valve servicing is
when the synthetic rubber seal (Nitrile or Viton) which can wear
during service eventually creates a small leaking condition in the
check direction. Valves subject to a high frequency of operations
may require spring replacement at earlier intervals. This should
become apparent when valve closure is noisy.
1. Caution. It should be realized that the valve cannot be serviced
under pressure. Steps should be taken to remedy this situation
before proceeding any further.
2. Removal from the pipe line for maintenance only requires the
removal of upper half of the flange bolts and the lower half being
loosened only.
DISASSEMBLY
1. Remove valve from pipe line.
2. Lay valve down with clapper assembly facing upwards (flow
arrow pointing up). Protect valve from damage.
3. Remove pipe plug.
4. Remove hinge pin. Slightly compress spring with hand tools to
allow easy removal.
One end of the hinge pin is threaded to assist in removal. Install
a mating threaded rod to serve as a tool when removing pin.
5. Carefully lift clapper and hinge arm assembly out of valve. Do
not damage seating surfaces of valve body. On larger valves it
may be easier to unbolt clapper from hinge arm.
6. Remove two thrust washer bushings and spring.
7. Remove 'O' ring seat seal in valve body with a small hand tool.
8. Inspect all parts for signs of wear or damage. Replace if nec-
essary.
REASSEMBLY
1. Reassembly is basically the reverse of disassembly steps.
2. Clean all parts.
INSTALLATION / OPERATION / MAINTENANCE
Series 501A
MODEL