The PVC drain pipe is the "blood vessel" of the building drainage system, while the valve is the "switch" that regulates the flow of water - choosing the right valve can make the drainage smoother, and choosing the wrong one can cause blockage, leakage or even system paralysis. Many people are always troubled when facing gate valves, ball valves, and check valves: what scenarios are they suitable for? In fact, the core of choosing the right valve is to match the "use requirements". Let's disassemble the characteristics and application scenarios of these three valves one by one.

First of all, it is necessary to clarify the premise of selection: first look at the medium (impurity content of sewage/wastewater), flow (pipe diameter and water flow size), frequency of use (whether to switch frequently), and installation location (trunk pipe/branch pipe/end). These factors will directly determine the "fit" of the valve.

Gate Valve: The "stable role" of the high-flow scene

The core structure of the gate valve is a gate that can move up and down. When it is fully open, the gate is completely withdrawn from the flow channel, and the water flow has almost no resistance - this is its most outstanding advantage. But the disadvantages of the gate valve are also obvious: the switching speed is slow (the handwheel needs to be rotated many times), and it cannot be in the "half-open and half-closed" state for a long time (the gate seal will fail due to water erosion).

So the gate valve is most suitable for high-flow, low-frequency switching scenarios: such as the drainage trunk pipe in the basement of the community (usually more than 100mm in diameter, responsible for the sewage discharge of the entire building), the main drainage riser at the bottom of the building (connecting multiple branch pipes, large flow and long-term open). These places do not require frequent operation of the valve, but more need "low resistance, high stability", the gate valve just matches.

Ball valve: "flexible player" in frequent switching scenarios

The structure of the ball valve is a sphere with a through hole, which can be completed by rotating 90 degrees to "full open/full off", and the switching speed is as fast as a few seconds; and the sphere and the sealing surface of the valve seat are tightly fitted, even if there is a small amount of hair and debris in the medium, it is not easy to leak. However, the flow channel of the ball valve is "reduced diameter" (the diameter of the ball through hole is slightly smaller than the diameter of the pipe), and the resistance is slightly larger than that of the gate valve, which is more suitable for small flow scenarios.

Its core application scenarios are positions that require frequent switching and small flow: such as the end of the drain branch pipe of the bathroom wash basin (which needs to be opened regularly to clean up blockages), the drain valve of the kitchen sink (which is often switched on and off to control wastewater discharge), and the drain pipe interface of the washing machine balcony (which must be opened every time the laundry is done, and closed to prevent odor from pouring back). These places value "ease of operation" and "sealing and leak-proof", and the ball valve is just right.

Check valve: the "safety guard" in the anti-backflow scene

Check valve has only one function - to prevent the reverse flow of water Its structure is ingenious: when the water flow is forward, the valve flap is pushed open by the water flow; when the water flow is reversed, the valve flap is closed by gravity or spring force, completely blocking the backwater. This valve does not require manual operation and is completely controlled by the automatic flow of water.

Its application scenarios revolve around "backflow prevention": such as the connection port between the washing machine drain pipe and the main pipe (when the water level of the main pipe is too high, it prevents sewage from pouring into the washing machine drum), the connection pipe between the septic tank and the building drain pipe (to prevent the stinky water from the septic tank from flowing back into the room), the bottom of the drain riser of the high-rise residential building (the low-rise residents are prone to "sewage backflow" due to excessive pressure in the riser, and the check valve can block the reverse water flow). The core requirement of these scenarios is "safety and leak prevention", and the check valve is the only

In fact, the choice of PVC drain valve is not so complicated: large flow gate valve, frequent switch ball valve, anti backflow check valve. The key is to think clearly "what problem this position needs to solve" - is it to flow smoothly? Or to operate easily? Or to prevent backwater? Follow the demand to find the valve, you can choose the most suitable one. After all, a good valve is not "expensive", but "just match the scene".