Differences between valves

Please have an expert answer this! This question is a bit profound!

A self-acting control valve is a control device that requires no external energy source; it relies on changes in the pressure, temperature, or flow rate of the medium being measured to carry out automatic regulation according to preset values, and it is an energy-saving instrument. It integrates various functions such as control and execution, forming an independent instrument control system on its own. It integrates the functions of a transmitter, a controller, and an actuator. Different from control valves in their general sense. Self-acting control valves include self-acting pressure (micro-pressure) control valves, self-acting (differential pressure) flow control valves, self-acting temperature control valves, and several other types. The self-acting pressure control valve is one of its members; thanks to its lack of need for external power, simple structure, ease of use, and low maintenance requirements, it is particularly suitable for urban heating systems, as well as in situations where there is no electricity or gas supply but control is still necessary. According to German reports, when this product is used in urban heating and heating systems, the thermal efficiency increases by 30% to 40% compared to before, resulting in significant energy savings. There is a pressure difference before and after the self-regulating valve; if it is installed in the wrong direction, the pressure at the back side will not meet the requirements for operation, and thus regulation will not be possible. The remote control valve is a hydraulically operated valve with multiple functions, and it is mainly installed at the inlet of water tanks or elevated water towers. When the water level reaches the set height, the main valve is closed by a float-controlled valve, thereby stopping the supply of water ； When the water level drops, the main valve is opened by a float-controlled pilot valve to allow water to flow into the tank, thereby enabling automatic water replenishment. The liquid level is controlled with precision, unaffected by water pressure ； Diaphragm-type remote control float valves can be installed at any position depending on the height of the tank and the available space; they are easy to maintain, debug, and inspect, offer reliable sealing, and have a long service life. Diaphragm valves feature reliable performance, high strength, and smooth operation, and are suitable for pipes with a diameter of 450 or less.