Crane WEINMAN 100, Инструкция по установке и эксплуатации, Страница: 6 / 12

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pump.
• Drain/Purge plugs furnished to routinely remove
foreign particles and protect pump and other system
components.
• Optional pressure tap allows monitoring of strainer
condition.
• Blowdown tapping supplied to protect pump seals from
drainage by foreign particles.
SUCTION DIFFUSER INSTALLATION:
1. Provide for distance “L2” (see Suction
Diffuser Catalog page for illustration and “L2”
dimension). “L2” represents distance necessary
for removal of strainer and stabilizing vanes.
2. Mount standard I.D. support leg and foot to pad
cast-on body of suction diffuser.
3. After piping and initial circulation are complete,
remove fine mesh start-up strainer.
4. If optional pressure tap is provided, a gauge can
then be connected to both the pump suction
and the Suction Diffuser’s schrader valve. An
increase in pressure drop will indicate when the
strainer may require cleaning.
SUCTION DIFFUSER MAINTENANCE:
It is recommended that the stabilizing vanes be
periodically inspected and the permanent strainer be
periodically cleaned. This will ensure smooth flow into
the pump and avoid damage to the pump components.
DISCHARGE PIPING
The discharge piping should never be of a smaller size
than the discharge connection of the pump and, in most
cases, should be one and sometimes two sizes larger
in order to avoid excessive frictional loss. Avoid sudden
or abrupt changes in pipe sizes which cause shock or
frictional losses.
Use increasers of the concentric type. Eccentric
increasers are not required for the discharge line.
Gate and check valves should be installed in the line with
the check placed between pump and gate valve. A check
valve, under most conditions of service, is required as a
protection to the pump against excessive surge pressure
when a foot valve is used on the suction, as well as for
protection against reversed rotation if no foot valve is
used.
In installations where noise is highly objectionable,
such as hospitals, hotels and apartment buildings, the
discharge pipe should not be attached to steel work or
hollow walls without being insulated properly against
vibration. In extreme cases, it is desirable that the dis-
charge line be provided with a flexible connection.
TDV DESIGN AND OPERATION:
The principle of operation for the TDV valve is extremely
simple. When in the open position, the clapper swings
out of the flow. If the flow stops, the spring allows the
clapper to close.
When closing the valve, a final “bumping” action with a
wrench gives the final positive seal closure.
TDV MAINTENANCE:
The TDV valve requires no day-to-day maintenance or
lubrication, but it is suggested that the valve be operated
once a month to assure it is in operable condition.
If at any time it is suspected that the valve is leaking,
either in the plug position or as a check, it is possible that
foreign particles are trapped between the mating faces
of the seal and seat, and are preventing tight seal action.
Cycling the valve from full open close causes a jetting
action that will wash away foreign particles that may be
trapped. Also, cycling the valve will usually squeeze any
build-up away from the seat mating faces and allow tight
shut-off again.
It is not uncommon to discover that when a TDV valve
has been reported leaking in the closed position, that the
valve is actually not completely closed. The cam-based
design of the TDV valve makes it almost impossible
to over-close. The TDV is designed to close at an
approximate ninety degree rotation of the plug stem.
To close the valve, rotate the stem on quarter turn and
tighten.
The TDV wrench is specially suited for the cam-based
design of the valve to assure a positive closure. The
most satisfactory closure is accomplished by turning the
plug to a tight fit and then “bumping” the plug lightly using
the TDV wrench. The use of cheater or a handwheel
should not be necessary.
If these procedures have been completed and a
tight seal is still not apparent, the valve should be
disassembled and inspected for damage of the clapper
seal and seat face, or for excessive wear of the clapper
pin and pin hanger supports.
For balancing procedures, please refer to the TDV
Catalog page.
Open Position
With the plug in the open
position, the clapper
operates as an efficient
check valve. The clapper
being hinged at an angle
provides 90% less dead
weight to minimize clapper
slam and chatter.
Balancing
The plug holds the clapper
at the selected flow
requirement for balancing.