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Trade Verify
Address: Wuliyao Industrial Zone, Yanshan County, Hebei Province, China
Contact name:Sam Cui
Hebei Lufeng Piping Equipment Co., Ltd. |
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Modern industrial equipment process request centrifugal pump are
basically work under condition of variable flow. An automatic
recirculation valve (ARC valve) is a multifunctional valve whose
primary purpose is to ensure that a pre-determined minimum flow is
assured through a centrifugal pump at all times. This is important
as centrifugal pumps
suffer from overheating and cavitation and can be permanently
damaged if they run dry.
Through many years of research and development, continuous
innovation and practice, shanghai datian valve Co. research ZD
series Automatic recirculation control Valve, to prevent
overheating, serious noise, unstable and erosion damage of
centrifugal pump under low load operation. As long as the flow rate
of the pump valve
below a certain value, the bypass backflow mouth will automatically
open to ensure necessary minimum flow of pump.
If you use centrifugal pumps for any liquid-boiler feed water,
condensate, or process fluids, a significant investment has been
made in the pump, driver and related controls. Minimum flow
protection is vital upon
pump start up and low demand conditions. If reliable protection
does not exist, the following unfavorable effects can interfere
with the performance and reliable operation of the pump. The
liquid’s temperature will rise due to friction and hydraulic losses
within the pump. Figure 2a illustrates the temperature rise in
relationship to the H-Q curve. The curve indicates that at or near
the best efficiency point,
the temperature rise is minimal and not significant to the pump
operation.
The process flow removes the generated heat from the pump. The
temperature increases as the flow through the pump is reduced.
Frictional and hydraulic losses generate heat, while the quantity
of fluid to which this heat is transmitted is reduced. The rise in
temperature results in the formation of vapor. The elevated
temperature / vapor pressure of the liquid results in problems
ranging from damaged seals and bearings to complete failure of the
rotating elements. Internal recirculation within the pump, often
termed incipient
recirculation, can cause a form of cavitation leading to impeller
damage. Internal recirculation is illustrated in Figures 2b and 2c.
High specific speed pumps have power curves which rise as the flow reduces. If adequate flow is not maintained, motor overload will result.
Continuous circulat ing system
Minimum requirement of continuous circulating system pump is
unrelated with the discharge of Process flow changes system. After
setting of minimum flow, through orifice plate directly backflow to
storage tank. Although continuous minimum flow circulation can
protect pump very good,but pump must provide greater power output
to ensure system process flow plus recycle flow, which causing
additional energy waste.
Control circulat ing system
Control circulatory system is assembly by the check valve, flow
gauge, minimum flow control valve, control circulation system,
control circulation system can provide minimum flow protection,
when process flow is greater than minimum flow of pump, loop
closed, no extra energy loss. But system is complex, control
components, purchase, installation, maintenance cost is higher.
Automat ic recirculat ion control valve
Automatic recirculation valve set check valve, flow perception,
bypass control valve, multi-stage step-down in one, do not need
power, control system and wiring, essential safety. Taking up small
space, reducing the possibility of high-speed fluid to
malfunction to minimum, with lower Installation and maintenance
cost,It is the priority pump protection way of modern industrial
process.
ZDT Model Automatic recirculation control valve
ZDL Model Automatic recirculation control valve
ZDM Model Automatic recirculation control valve
