Function: The dynamic flow balance valve keeps the flow constant between 31-600KPa.
Role: Keep the flow through the valve constant.
Theory: When the incoming flow pressure P1 increases, the sleeve of the valve sleeve moves downward, compressing the spring inside the valve bladder, and reducing the flow area of the valve hole at the bottom of the valve bladder, that is, reducing the Kv value of the valve bladder. Thus, although the pressure difference 螖P across the damper is increased, the Kv value is reduced, and the product of the two, that is, the flow rate Q, remains substantially unchanged under the action of the spring.
The pipeline of the constant flow system is installed at the end without stepping.
The pump system is chilled water pump and cooling water pump to prevent the pump from over-flowing when the number of units changes.
A place where a constant flow rate is required, such as a cooling tower.
Water supply pipes or return pipes can be installed.
Selection and precautions
Selection: Only according to the flow selection.
A. The valve pressure working range is greater than the minimum starting pressure difference.
B. It cannot be installed in series with the proportional integral electric control valve.
Constant flow system hydraulic balance scheme
Dynamic differential pressure balancing valve
Theory: The high pressure upstream of the electric regulating valve is guided to the lower side of the control bellows through the pressure guiding tube; the pressure downstream of the electric regulating valve is guided to the upper side of the control bellows through the external pressure guiding tube or the internal pressure guiding hole.
When the pressure on the high pressure side rises, the bellows moves upwards, causing the valve stem and the valve cone to move upward, causing the pressure on the medium pressure side to rise, thereby dynamically maintaining the pressure difference between the medium pressure side and the high pressure side and the spring. The preset force balance ensures the dynamic constant of the pressure difference across the electric control valve. When the pressure on the high pressure side is lowered, the bellows moves downward, and the situation is similar.
Adjust the differential pressure of the spring to adjust the differential pressure setting.
Function: Dynamically keep the pressure difference between the controlled points constant at the set value.
Function:
Ensure dynamic hydraulic balance of the controlled system to prevent dynamic imbalance in the system.
Prevents noise and vibration from being generated by the electric control valve regulating valve.
The regulating valve in the system can be selected with a driver with less driving force to avoid the danger of burning the valve.
Provides good valve authority for the regulating valve, ensures the realization of the linear heat-dissipating controlled system, and ensures the rapid and stable system.
The debugging workload is very small, the installation cycle is accelerated, and debugging can be avoided when the system is changed or expanded.
Conveniently correct the difference between actual and design conditions.
Maximum flow limit function.
Ensure dynamic hydraulic balance of the controlled system.
The dynamic differential pressure balancing valve dynamically maintains the pressure difference 螖P between the controlled points constant at the set value, and the Kv value of the other unoperated electric regulating valve does not change, so the water quantity of the branch is dynamically constant. The amount of water in the branch changes only when the electric regulating valve is actuated, that is, when the Kv value changes.
Prevent electric noise and vibration from the electric control valve.
The adjustment valve uses a driver with a smaller driving force.
The pressure difference between the two ends of the electric regulating valve is constant, and the pressure fluctuation of the system is absorbed by the dynamic differential pressure balancing valve. Therefore, the adjusting valve uses a driver with a smaller driving force.
Provides good valve authority for the regulator valve.
Definition of valve authority:
The pipeline of the fixed and variable flow system is installed at the end without step by step.
The pipeline, branch pipe or riser of the variable flow system is installed without stepping.
The valve of the single-pressure pipe must be installed back to the water, and the valve water supply or return pipe of the double-pressure pipe can be installed.
Selection: The valve body is selected according to the Kv value. The Kv value of the selected valve is greater than the design value. The valve pressure drop is used to calculate the valve Kv value, not the control pressure difference. Select the drive with a controlled differential pressure.
Dynamic differential pressure balance electric control valve
Theory: The essence is that a dynamic differential pressure balancing valve and an electric regulating valve are combined into one. The valve is a double valve cone structure, the upper valve cone is the valve cone of the electric regulating valve, and the lower valve cone is the valve of the dynamic differential pressure balancing valve. Cone, the dynamic differential pressure balancing valve provides a constant pressure difference (0.2Bar or 0.5Bar) before and after the electric valve cone (upper valve cone). The pressure fluctuation of the system is absorbed by the dynamic differential pressure balancing valve, when the electric valve cone ( When the upper valve cone is not actuated, the valve flow capacity kv is constant, and the pressure difference 螖P is constant, so the flow rate Q of the valve is constant; only when the electric valve cone (upper valve cone) acts, the flow through the valve will Changes have occurred, thus achieving a perfect unification of dynamic balance and adjustment functions.
Process: The upper and lower ends of the diaphragm form a balance with the force of the internal spring, ie P1 = P2+P spring.
When the system pressure fluctuates, when P1 increases, the balance is destroyed, and the force below the diaphragm is greater than the upper side, so the diaphragm will move upwards, close the small differential pressure control valve spool, so that P2 increases and reaches equilibrium again. Show.
On the contrary, the differential pressure control valve is opened so that the pressure difference of the regulating valve spool is always constant throughout the operation of the switch, so that the flow rate change through the valve is only one-to-one corresponding to the opening degree of the regulating valve.
The pipeline of the variable flow system is installed at the end without stepping.
The main advantage:
1. The occupied space is small, and the automatic balance of the system is good.
2. One leak point is missing for each group of valves.
3. Easy to install and maintain.
Disadvantages:
1. It is not as flexible as the split solution (dynamic differential pressure balance valve + electric control valve), and the differential pressure of the split solution can be adjusted on site.
Variable flow system hydraulic balance scheme
Solutions to common phenomena of hydraulic imbalance:
1. The system is uneven in temperature and heat. The running energy consumption of the pump is too high 鈫 hydraulic calculation, reasonable piping, the same program, static balancing valve. Dynamic differential pressure balancing valve or dynamic flow balancing valve, integral valve.
2. Variable flow system operation is out of regulation. The load is stable, but the room regulating valve moves frequently, causing the room temperature to fluctuate frequently. The system stabilization time is too long 鈫 dynamic differential pressure balance valve or integral valve.
3. The regulating valve produces noise and vibration. The regulating valve is not closed, and there is a danger of burning the valve in severe cases. The valve of the regulating valve is too small, the curve of the valve is deformed, and the linear heat-dissipating controlled system becomes a controlled system of the throwing heat. Dynamic differential pressure balancing valve or integral valve.
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