In order tobetter manage the work of each department, facilitate interdepartmental cooperation and improve working efficiency, Dervos officially released the company's ISO system document - DVS-procedure document on April 1, which will be officially implementedfrom the day   Thenew ISO system documents include a total of 31 specification documents,coveringall the content of the existing departments of the company. These documents provide guidance and requirements for howDervos could manage production and serveour customers in a more thoughtful and effective way.   Dervos, exploring the valve market for more than ten years, insists on bringing better quality products to the market. In the downturn of the market environment hit by the epidemic, we are still seeking and improving, hoping to serve our customers better.

A check valve for water applications requires as much considerations as you would collect in any other valve selection. Same as various other media, water has its own unique features curve that should beaccommodated to the valve for specific use in those media. Of course, this is an simple matter, but some less obvious reasons may be included when it come to choosing the perfect check valve for water. Problems with water delivery Water Hammer: Although this hydraulicproblem can bediscerned in other fluids, water hammeringhits when the medium is forced to stop or change direction suddenly. As water or other media is trapped in the pipe with only two directions to pass,thissituation comes with vibrationsof the pipe andirritating noise. Both hurt the system. Transporting water is aordinary thing incountless applications, but it remains ahard case nowadays because it’s almost impossible to maintain the flow indefinitely steady.The mostcommoncause of water-hammer is when a pump stops working without any warning. Water flows backwardtothe pump, because the check valve is not able toreact fast enough. Water hammer is sometimes referred towater slam. Reverse Flow: If left unchecked, reverse flowof water orany medium canrender the pump spin backwards, causingunexpected damage. Likewise,ifwater flows in the wrong direction, for any length of time, itwill hurt the entire system seriously. Unlike a backflow preventer, which consist of, work intandem with multiple check valves, a single check valve is notapanacea. Valve chatter: Valve chatter occursif valves open and close constantly and frequently. Valve chatter can cause damage to the valve and piping and can inflict totalfailure to the system. Checking for water problems Though check valves areremarkable reliable and endless new model and design are brought to the field every year, allproblems theytry to answer to are just these three listed above. Due toits simple structure, it can be immune from external factorslike power failure, but is still affected by flow direction, and by check valve design features and defects. There are two basic designs of check valves. One uses a disc (basically a flap) and one uses a free floating ball. They both have a single direction, which means that their job is to prevent water from flowing backwards through the pipe. Both types have advantages and disadvantages, but perform the same job with fairly equal success.Ultimately, however, the success of a check valverest with an not-too-fast-or-too-slow action. Finally, like mostvalves, its sealing performance determinesthe success of a check valve . All of these things should be taken into account when selecting a check valve.

Check valve is a valve thatits opening and closingpart relies on the medium flow and force tomove, precluding the backflow of the medium.As one ofautomatic valves, check valvemainly used for one-way flow of media on the pipeline, allowing the media to flow in one direction only.The fluid under pressure makes the valve flap open and flow from the inlet side to the outlet side. When the pressure on the inlet side is lower than the outlet side, the valve flap automatically closes under the action of fluid pressure an   Check valve according to its structural characteristics can be divided intoWAFER check valve, lift check valve, swing check valve, counter weight check valve, etc.   WAFER check valve   1. Compared with swing check valve, the flow resistance is large,Wafer check valve isnot suitable for theoutlet of high pressure (Class900 and above) pumps and compressor; not suitable for pulsating media conditions;not suitable for oxygen conditions.   2. Because it’s Structure of WAFER,Wafer check valve isnot suitable for large diameter (DN600 or more), high pressure (Class900 and above) occasions.   3. Wafer check valve should as far as possibleinstalledhorizontally. In case of vertical pipeline, make sure the media flowfrom top to below.   Lift check valve 1. Subject by the working principle,lift check valve can only be installed in the horizontal pipeline.   2. Compared with the swing check valve,its flow resistance is large,lift check valve isnot suitable for large diameter (DN50 and above) occasions, in general,it’ssuitable for DN40 and smaller application.   Swing check valve   1.  Swing check valve should as far as possibleinstalledhorizontally. In case of vertical pipeline, make sure the media flowfrom top to below.   2.  limited by the structure,swing check valve should not be used for DN40 and below on the pipeline.   3. For large diameter pipelines (e.g. DN400 and above), Tilting swing check valves arerecommended.   Counter weight check valve   1. Choose according to needs 2. Counter weight check valveis used inwhere serious water hammer may occur.