1. Balancing valve dynamics operating principles
It is mainly through changes in the flow Disc balancing valve
the area around the valves to adjust to the change, thus achieving
the purpose of flow control. When we mention the balancing valve
dynamics, we usually mean the throttling element whose local resistance
could change. The equation of simplifying flow for the incompressible
fluid is as followed:
Q=KA£¨¡÷P£©, Q--the flow through
the balancing valve£»K--the flow coefficients of valve
opening£»A--open area of valve disc
¡÷P--pressure difference around the valve, at the
premise of unaltered valve opening, the change of K could be negligible.
Therefore, we should make A£¨¡÷P£©unchanged
to keep the flow constant.
Moreover, the balancing
valve is made up of disc whose open area is changeable,
spring with high degree of accuracy£¨¡À5£¥£©and
support device. Once the spring receives the pressure difference
it will control the size of open area automatically so that the
flow through valve could be constant.
This valve is the control part in the transfer system of pipeline
fluid and it is used to alter channel section and medium flowing
direction. Its main function is stream guidance, stop, regulate,
and throttle, non-return, distributaries, diverter, over flow
relief and so on. The valves used for flow controlling have wide
varieties and specifications, from the simplest globe valve to
complex valves used in the autonomous system, the nominal diameter
from the tiny meter valve to 10m industrial pipeline valves. The
valve can also be used to control the flow of some fluid, such
as water, steam, oil, gas, mud, some corrosive medium, and liquid
metal and radioactive fluid. The working pressure of this valve
could be from 0.0013MPa to 1000MPa and the working temperature
from -269¡æ to 1430¡æ. The operation of
the valve could adopt manual, electric, pneumatic, and hydraulic,
gear box, Eletro magnetic, solenoid& hydraulic, electric&
hydraulic, pneumatic& hydraulic, spur gear, bevel gear; which
all could be simply open or closed according to the required scheduled
action or independent of transducing signal when under the effects
of pressure, temperature or any other transducing signal. With
the help of driving the disc could be rising and falling, slippage,
swinging or swiveling and also achieve the control of the flow
area size in the end.
2. Balancing valve
dynamics working process
When the pressure difference around balancing valve is less than
the minimum start-up pressure is because of the uncompressed spring,
in this case the passage area is the largest. When the pressure
difference around balancing
valve is in the working scope disc will compress the
spring and then the water flow through the round holes on both
sides of the disc and geometry type channel. Under the movement
of disc the geometry type channel both sides will be affected
and changed also with the passage area, so the water flow rate
will mainly keep constant in such pressure difference range. When
the pressure difference around balancing valve surpassing the
working scope means the disc is completely compressed by spring.
The water only flow through the round holes on both sides of disc.
In this case the disc becomes the fixed adjustor and the flow
rate is proportional to the differential pressure and rises with
the increase of pressure difference.
The balancing valve dynamics have some affective characteristics,
limiting the max flow of end equipment of the air conditioner
in some pressure range, keeping the flow constant automatically.
In the large, complex, non-constant air conditioner heating project,
the valve could simplify system testing process and shorten the
testing time. Specially used in the direct return water system,
the valve could be easy to achieve water power duty balanced,
meet the need of environmental temperature designed and keep the
end equipment of the air conditioner no interacted by any other
ends' operation.
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