- First, the scope of application is limited
calibre limitation: usually applicable to DN50 to DN600 small and medium diameter pipeline, large calibre (such as DN600 or more) need to be specially customised and higher cost.
Pressure and flow restrictions: mainly used for low pressure, small flow media environment, high pressure or large flow conditions performance is limited.
- Second, the performance and reliability of the problem
sealing instability:
lifting type although good sealing, but the flow resistance is large, affecting the fluid efficiency;
rotary flow resistance is small, but the sealing performance is poor, easy to shut down due to impurities in the medium is not strict.
Spring failure risk: after long-term use, the spring may be fatigue or failure, resulting in delayed or incomplete closure.
Water hammer effect: rapid closure of the valve flap during sudden changes in flow rate may cause vibration of the piping system or water hammer impact, damage to equipment.
Media sensitivity: the valve closing effect is easily affected by the cleanliness of the medium, containing particles or viscous fluid may lead to seal failure.
- Third, the installation and maintenance defects
maintenance complex: need to dismantle the two sides of the flange in order to overhaul or replace internal parts, high maintenance costs and cumbersome operation.
High installation requirements: improper installation may lead to water leakage or water pressure fluctuations, requiring professional technical support.
- Functional limitations
Non-adjustable: only one-way non-return function can be realised, unable to adjust the flow or pressure.
Type selection contradiction:
Lifting type (high sealing but high resistance) and rotary opening type (low resistance but low sealing) can not take into account the performance, need to be based on the scene of the trade-offs.
- Summary
The shortcomings of the pinch check valve are mainly concentrated in the narrow scope of application, sealing stability is not enough, maintenance is complicated and a single function, etc., the selection of specific conditions (such as media characteristics, pressure and calibre) need to be combined with the weighing of the advantages and disadvantages.
