1. The definition of a valve is a device used to control the direction, pressure and flow of a fluid in a fluid system. Valves are devices that flow or stop the media (liquid, gas, powder) in piping and equipment, and control the flow.
2. Manual regulating valve is to change the flow of system fluid by means of manual power operation.
3. In the heating and heating pipe network system, if there is only one main pipeline and no branch pipeline, there is no need to install a regulating valve; only when there are more than two branch pipelines in the system, for the pipe network system Only when the hydraulic balance is required, a manual adjustment valve is installed in the water supply or return water of each branch.
4. “Regulation” – as the name implies, it is to adjust the quantity or degree to suit the requirements; that is to say, the flow of each branch pipeline should be adjusted to the best required flow, not the total required by the system. flow decreased. Therefore, no matter whether the regulating valve is installed on the water supply or return pipeline, as long as the total flow of the system is not less than the flow rate calibrated by the nameplate of the pump, there is no so-called “cavitation” problem. Conversely, if the regulating valve is installed on the water supply pipeline of the system, if the total flow is less than the flow rate calibrated by the nameplate of the pump, what will be the consequences?
5. As the moderator teacher said, “it has been used in the return water pipeline before, and many materials are like this”, yes, the author has been engaged in HVAC work for many years, and has installed, managed, and debugged many heating and heating pipe network systems, regulating valves They are all installed on the return pipe of the branch system. Never seen a water pump “difficult to start” and “cavitation”.
6. In the heating and heating system, due to improper selection of the circulating water pump, such as too high lift, the characteristic curve of the water pump after operation does not match the characteristic curve of the actual pipe network system, resulting in excessive flow of the pump and excessive current of the motor and cannot run. At this time, the valve at the outlet end of the pump can be used as a regulating valve, and the valve can be properly closed to make the circulating pump run normally.