control valve Instrumentation

What is a balancing valve?

What is a balanced system and what is the need for balancing?

A balanced system can be defined as a distribution system that has proper flow in the whole system corresponds to the flow rate that is specified for the design of the system. If the proper balancing of the system is not done then it could cause the unequal distribution of the flow and because of this, there will be a surplus effect in some of the terminals. It is not possible to make a properly balanced system by manipulating the piping or altering the pipe dimension only. In order to get a balanced system proper adjustment of the balanced valve is needed.

What is a balancing valve and why are they used in a hydronic system?

A balancing valve can be considered as a combination of a regulating valve and flow measuring device in one piece of the body. We can see a balancing valve in a hydronic system to achieve a proper balancing of water flows in hydronic heating and cooling system. The balancing valve could perform as a shut-off valve, a flow measuring device, and also a flow adjusting valve. The balancing valve can accurately measure the terminal flow in the commissioning process, the balancing valve also has a mechanical memory in order to permit the reopening of the valve to its correct position after servicing the terminal. A manual balancing valve should be balanced because the balancing procedure can detect most of the hydronic faults during the commissioning operation.

What is a static and dynamic balancing valve and how do they work?

The balancing valves are of two types they are static and dynamic balancing valves. The balancing valve could provide proper flow in a system and can increase the system’s efficiency.

Static balance valve

The major feature of a static balance valve is that the open orifice area can be changed manually and can be fixed into a static value. So now the flow coefficient can be obtained and by checking the wheel position, and this valve is connected with measuring equipment to do the indirect flow measurement. This valve can be pre-adjusted according to the calculated pressure distribution in the HVAC system.

Dynamic balancing valve

The major feature of this valve is that it can be adjusted to a given flow and it can be locked to ensure this flow. This is an automatic regulator valve and it would regulate with reference to the differential pressure automatically adjusts to the flow coefficient in order to maintain the required flow. The flow coefficient of the valve automatically compensates for any changes of the differential pressure and because of this, the flow will never exceed the preset flow.

What is a thermostatic balancing valve?

A thermostatic balancing valve is used in a hot water circulating systems utilizing circulating pumps. This valve would regulate the flow rate by checking the water temperature continuously by a thermostat. Thus the hydraulic balancing is maintained automatically. Mostly these valves are installed in horizontal or vertical positions. The thermostatic balancing valve must be selected for a pipeline according to the intersection of the flow rate and also according to the required pressure drop.

What is the need for balancing?

If the correct balancing of the system is not done then it could cause unequal distribution of the flow and this could cause a surplus effect in most of the terminals. The result of an unbalanced system will be that the proper heating and chilling won’t be achieved. If the proper balancing is done then correct flow in boilers and chillers can be achieved, and also the proper distribution of the flow in the system can be achieved.

How to install a balancing valve?

The balancing valve must not be placed on the supply side, the standard ports and handle must clear thick insulation. The balancing valve must be on the return side of the coil it should be located just before the exit isolation valve.

What is an automatic balancing valve?

The automatic balancing valve has an automatic device that can maintain a constant flow in hydronic systems when there are pressure fluctuations. These valves are mostly used in constant variable systems and also in variable volume systems.

What are the advantages of a balancing valve?

  • System accuracy can be increased
  • Proper flow can be achieved in a system with the help of a balancing valve
  • Dynamic system balance can be achieved
  • It can save the pump energy
  • It can do flow measurement and balance
  • It can also detect the pressure
  • These valves can be used for both the heating and cooling applications

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