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Double expanding through conduit gate valve is one kind of bilateral forced sealing valve with the capability of protecting the sealing surface, this type of expanding through conduit gate valve can be widely installed onto pipelines and storage devices for oil products, natural gas and oil, and corrosive medium such as acid and alkali etc.
Sealing Principle:
Gear-driven device drives the stem making the main gate up and
down, the sub-gate will move alone with the main gate under the
force of link rod, Double expanding through conduit gate valve
realize its on/off activity in this way, the gate will be expanded
when the valve is fully opened or closed to control the medium.
Gates Structures:
The two-piece gates are on the start and end position of moving
process, because of changing of main gate and sub-gate according to
incline position making two sealing surface of two-piece gates
bring closing and expanding action. These actions can realize
effective sealing and protect the sealing surface during valve
open.
- When fully opened, the pair inclines of the two-piece gates will
be expanded till they are stick to the seats preventing medium and
impurity from entering.
- During the process of opening and closing, the pair inclines of
the two-piece gates will close to the two sides of valve ensuring
the gates moving freely
- When fully closed, the pair inclines of the two-piece gates will
detach and making the two sides of gates closing to the sealing
surface to enhance a perfect sealing
Features:
Full Bore Design making the Double expanding through conduit gate
valve suitable to be placed on pipelines to be cleaned by tube
cleaner, causing no block or damage to the valve itself and other
fittings
Floating seat structure design to realize flexible and rigid double
sealing capabilities. Deposit weld high-hardness alloy onto sealing
surface forming a metal to metal structure, both structures can
realize bilateral enforced sealing.
With unique top assembling design, professionals or well-trained
maintainers can replace the valve trims online – without
dissembling
When the Double expanding through conduit gate valve is fully
opened or closed, the chamber isolates from medium completely, by
this way, under an accident condition, open the empty valve and
draining valve to relieve the pressure firstly, and then carry out
the malfunction remove, drainage and packing replacement.
When accidental leakage happened to sealing, relieve the pressure
through grease injection, and the injection sealing gum into it, in
order to carry out the next step, this method can only be used as
an emergency management before taking measure.
Because of absolutely bilateral sealing don’t relieve the pressure
through the sealing surface to pipeline when the pressure in
chamber rises abnormally due to temperature rising or
metallographic variation, but relieve it through safety valve
placed on the valve body to keep safety for the pipeline and
devices.
Double expanding through conduit gate valve is with fire safe
design to API 6FA or JB/T6899
The position of installation is flexible which can be vertically,
horizontally reversely and obliquely installed.
Manually operated valve is with hand-wheel or gear device. When the
Double expanding through conduit gate valve is operated by
actuator, different ways of operation can be adopted according to
different customers’ requirements and different situations. Such as
pneumatic actuator, hydraulic actuated, electric actuated, to
realize quick opening and closing, site and remote control and
program control through computer. With pneumatic actuator, the
valve can be opened and closed rapidly within 15S to finish the
whole travel.
Double expanding through conduit gate valve can be connected with
pipelines through flanged or butt welded ends to ANSI, API, JIS,
ISO and BS Standards etc.