Stop Valves are closed by screwing a rubber gasket down onto a seat in the middle of the valve. Pros only use small versions that act as shutoff valves for fixtures such as sinks and toilets and outdoor sillcocks. Flow is inefficient because of the circuitous route the fluid (water, in most cases) has to follow. It's important to orient the valve in the right direction with the arrow (cast into the side of the valve) aligned with flow direction. That way, water flows against the bottom of the rubber gasket. If the valve is put in backward, the flow will force the gasket away from the top of the valve. Stop Valves, Shower Stop Valve, Water Stop Valves, Brass Stop Valve ZHEJIANG KINGSIR VALVE CO., LTD. , https://www.kingsir-valve.com
Metering pump basics
Dosing pump is designed for measuring the liquid pump. The vast majority of metering pumps use both piston and diaphragm pumps (see reciprocating pumps) and are also useful gear pumps because they maintain a constant flow independent of discharge pressure. There are two kinds of metering pump flow can be adjusted and can not be adjusted, the former is more applicable. The flow rate is mainly adjusted by changing the stroke length, such as changing the radius of the crank, the position of the back stop point on the plunger return stroke and the gap between the plunger rod and the crosshead. The flow rate can also be adjusted by changing the reciprocating frequency or both. Although the stroke length can be adjusted from zero to maximum, but in order to ensure measurement accuracy, are generally limited to 30 ~ 100% range. Metering pump metering accuracy refers to the accuracy of flow reproducibility, usually calculated according to the maximum flow rate. In the 10 ~ 100% adjustment range, the measurement accuracy of the general metering pump is ± 1% (special metering pump accuracy is higher). The main factors that affect the measurement accuracy are the sealing of the plunger packing and the integrity of the suction valve and discharge valve. Plunger metering pump has the advantages of high metering accuracy, wide adjustment range and high pressure. It only leaks at the packing seal, which will affect the metering accuracy of the pump after the packing is corroded and worn. This metering pump flow is generally 4 ~ 4000 liters / hour, the pressure is generally below 5 × 105 Pa. The main advantage of the diaphragm metering pump is that it does not leak and is therefore particularly suitable for applications where leaks are not tolerated, such as delivering flammable, explosive, toxic and radioactive media and also delivering liquids containing solid particles so it develops very fast . This metering pump flow is generally below 2500 liters / hour, the pressure can be 35 MPa. The use of metering pumps enables the delivery, metering and adjustment of three functions, simplifying the production process, automating and semi-automating and improving product quality. Using multiple cylinders or multiple metering pumps, several media can also be fed into the reactor at an accurate ratio for mixing.