First, observe the shape of the valve handle.
Looking at the shape of the valve handle is the most common way. The handle of most in-line valves is hexagonal, with two sides parallel to each other. Observe the positional relationship between the parallel sides of the handle to determine the direction of valve opening and closing. When the parallel edge coincides with the pipeline axis, it means that the valve is open; When the parallel edge is perpendicular to the pipeline axis, it means that the valve is closed.
Second, find the logo.
Some in-line valves will be marked with arrows or letters in the opening and closing direction on the handle or valve body, which can simplify the user's identification process.
Third, the direction of water flow indication.
For linear valves with water as the medium, the opening and closing direction of the valve can be judged by observing the direction of water flow. This method is especially suitable for valves that have been connected to the pipeline.
Four. Vertical direction indication
Some in-line valves are equipped with a small indicator on the handle, which can be rotated or flipped to indicate the opening and closing direction of the valve.
Introduction to valve classification:
1, check valve
This kind of valve is used to prevent the medium from flowing backwards. It opens itself by using the kinetic energy of the fluid and closes automatically when it flows backwards. Stand at the outlet of the water pump, the outlet of the steam trap and other places where the fluid is not allowed to flow backwards. Check valves are divided into swing type, lift type and clip type.
For swing check valves, the fluid can only flow from left to right, and automatically closes when it flows in the opposite direction. For the lift check valve, when the fluid flows from left to right, the valve core is lifted to form a channel, and when the fluid flows in the opposite direction, the valve core is pressed against the valve seat and closed. For the wafer check valve, when the fluid flows from left to right, the valve core opens to form a channel, and when the fluid flows reversely, the valve core presses on the valve seat and closes. Wafer check valves can be installed in multiple positions, with small volume, light weight and compact structure.
2. Control valve
The pressure difference before and after the valve is constant. When the opening of ordinary valve changes in a large range, its flow rate changes little, but when it reaches a certain opening, the flow rate changes sharply, that is, the regulation performance is not good. The regulating valve can change the resistance of the valve by changing the stroke of the valve core according to the direction and magnitude of the signal, so as to achieve the purpose of regulating the flow.
Regulating valves are divided into manual regulating valves and automatic regulating valves. Manual or automatic regulating valves are divided into many types, and their regulating performance is also different. Automatic control valves include self-operated flow control valves and self-operated differential pressure control valves.
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