Using a special type of axial-flow check valve, in order to ensure the safe and efficient operation of equipment, piping systems

With the large domestic oil refining and ethylene and other petrochemical projects and the new expansion , long-distance oil and gas pipeline systems and large ethylene plant compressors and large pumps and other working conditions more demanding pipeline system that requires selection of quick closing , low pressure loss and noise valve. Especially the gas medium , for ordinary swing , dual plate check valves,  High pressure ball valve  is often not fully open , resulting in medium flow instability, pressure loss , prone to mechanical vibration , noise, large , etc., thus  Needle valve  a large compression the normal operation of the pump unit . Then you need to use a special type of axial flow check valve, in order to ensure the safe and efficient operation of equipment and pipeline systems . Axial quick closing check valve function . Axial flow check valve and swing , dual plate check valve , compared short trip, especially the relatively large  Check valve  stroke is shorter , you can achieve rapid closure . The fluid system the damaging effects of water hammer to a minimum. Axial flow check valve closed completely along with the reverse flow of fluid , short stroke valve ensures fast dynamic response, and reverse flow through the valve to a minimum , thereby preventing the risk of water hammer phenomenon occurs . Turn to protect equipment from damage caused by fluid backflow . Can completely prevent the media back cause upstream device damage.

Elaborated resistivity backflow prevention device backflow prevention performance

Currently on the market there have been some low resistance, energy-efficient new backflow prevention device. As its name with "low resistance", "backflow" This attractive words, but also in the popular and raise doubts and controversy, and continues not broken. The following will explain the dynamic hydraulic control point resistivity  Instrument needle valves  prevention backflow prevention device performance, given prior to analysis and recognition industry consensus standards. Consensus 1: backflow prevention device is defined as "a strictly limited water pressure in the pipeline only one-way flow of hydraulic control combination device." The so-called strict to prevent  Male connector shall include: ① can prevent all conditions occur  Check valve reflux; ② can prevent all conditions occur siphon reflux; ③ outlet end as long as the media back to the inlet side, are called backflow contamination. Consensus 2: backflow prevention device structure is characterized by a two-return unit and drain drainage device component. Therefore, any discharge drainage device does not include backflow prevention devices are not called backflow prevention device.

Swing check valve and nozzle check valve, two identical pump conditions

Select the correct meaning and principles of the check valve in the hydraulic system pump , check valve plays a very important role, but it also brings a lot of trouble . Central power plants such as the UK , 16% of accidents are caused by a non-return valve which stops unexpectedly leaving the pump check valve closed water hammer accident rate is highest. Such water hammer strength not only by the impact of the entire hydraulic system , but also by the characteristics of the check valve itself . Two  High pressure ball valve  parallel springs station system that they were installed at the pump outlet DN 600 swing check valve and nozzle check valves , two pumps  Valve manifolds  are identical, while three parallel pumps have a when the pump stops unexpectedly , two kinds were measured downstream of the check valve of the water hammer pressure variation parameter , as shown in Figure 2 . Figure 2 curves show the characteristics of the water valve itself has a great  Check valve  of impact, therefore, of a particular line , the correct choice of the pump station valve is particularly important. The selection of the ideal valve should follow the following principles : ( 1 ) check valve must have the ability to resist corrosion pumped medium ; ( 2 ) check valve nominal pressure with the working system to match ; ( 3 ) check valve fully open resistance losses must meet the technical design requirements, normal working hours, should be able to ensure full ;