Q&A-Knife Gate Valve

Knife gate valve is also called slide gate valve (sliding gate valve). Knife gate valves should only be used for applications requiring a completely open or completely closed position and should not be used to regulate flow unless they are designed for it. Whenever fluid is forced against a partially closed gate, there will be a vibration, gradually eroding the disc and seat. In addition, the knife gate valves are designed to slowly open and close to safeguard against the impacts of water hammer.

One of the differences between the gate and the knife gate valves, is that the knife gate valve often has a sharpened disc to better cut through slurry/viscous media. Also, the knife gate valve has a short face-to-face length compared to a gate valve, which is dimensionally wider. As a consequence a knife gate valve is light weighted compared to the gate valve. These are the main differences and probably two of the biggest advantages of the knife gate valve.

Knife gate valves are used is a lot of processing plants today and come in large sizes which make it easier to handle thick flows of light grease, heavy oils, varnish, slurry, waste water and paper pulp. It’s important to note that these valves do have low-pressure limitations and are designed to seat the blade into an elastomer seal once the blade cuts through the substances its handling. Thick liquids easily glide over these soft seals with no interference, however, when a solid mass or powder passes through the knife gate, the bulky, dry material ends up packing into the soft seals located at the end of the gate. When this happens, the seals eventually will not close tightly enough. If this happens the seals will need to be replaced.

The main reason for choosing a knife gate valve is that they are cost-effective, easy to actuate and light. They are also extremely effective in many industries and processes. Knife gate valves were designed with a sharp edge to cut through the pulp and seal. With this type of useful attribute, the knife gate valve has become invaluable in applications involving slurry, viscous fluids and other systems where impingement is an issue.

There are two major reasons why the leakage happens on your knife gate valve. 

1. External leakage-check: whether the filling material is installed normally or wear-out.
   
   
2. Internal leakage-check: whether the knife gate valve is installed normally; check whether the valve seat of the knife gate valve is wear-out or damaged.

 Yes, our knife gate valve is easy to have maintenance. The valve forged as one complete piece with few parts installed, providing easy maintenance, and also features with modularized design on standard accessories allows easy maintenance and replacement. And either KVC, KGC, KEC, KUC or KAC are both pneumatic operated knife gate valves.