A ball valve is a shot-valve that controls the flow of a liquid or gas using a rotating hole with a hole. By rotating the ball about a quarter (90 degrees) around its axis, the fluid can pass through or become blocked. They have a long shelf life and provide reliable seals throughout their life, even when the milk is not used for a long time. For a complete comparison, read the article Sliding Valve vs. Ball Valve. In addition, they are more resistant to contaminated environment than other types of valves. In special versions, ball valves are also used as control valves. This program is less common than other types of control valves due to the relatively limited accuracy of the flow control. However, milk also offers benefits here. For example, it still guarantees a reliable seal, even in the case of dirty media.
Common types of ball valves
Standard threaded ball valve
Standard ball valves include housing, seat, ball and lever for ball rotation. They include two-, three-, and four-port valves, which can be female or male threads or a combination of them. Threaded valves are the most common and come in a variety of forms: approved for fluid or specific applications, small ball valves, angled ball valves, ISO-top ball valves with integrated filter, and the list goes on. They have a wide range of options and a wide range of performance for pressure and temperature.
Flange ball valve
The flange ball valve is determined by the type of connection. The ports are connected to the piping system through flanges, which are usually designed according to a certain standard. These valves offer high flow rates because they usually have a full-bore design. When choosing a flange ball valve, in addition to the working pressure, you should also check the flange class, which indicates the highest pressure that this type of connection can withstand. These ball valves are designed with two, three or four ports, can be approved for specific fluids, have ISO-top and other items that a standard rotary valve can have. They are usually made of stainless steel, steel or cast iron.
Valve ball valve
Vent ball valves are almost like double-sided threaded ball valves when we look at their design. The main difference is that the outlet port is in a closed position depending on the air environment. This is achieved with a small hole drilled in the ball and in the valve body. When the valve closes, the holes line up with the outlet inlet and release the pressure. This is especially useful in compressed air systems where decompression provides a safer work environment. Visually, these valves look like two-way ball valves.
Manual and automatic taps
Manual ball valve
The handle is attached to the stem of the valve and is able to rotate the valve from the open or closed position (90 degrees). Properly installed, the valve opens when the handle is parallel to the pipe and closes when the handle is perpendicular to the pipe. It is important to pay attention to the direction of the handle to know if the valve is open or closed. There are other types of ball valve handles, such as locking handles or ball valve gearboxes. They act as their name implies. If you have a larger ball valve or need more torque to open or close the valve, you may need a ball valve handle. If your handle breaks, is incorrectly installed, or you are turning the automatic ball valve manually, you can purchase a ball valve handle replacement.
Automatic shut-off valve
Instead of manual operation to disconnect or connect the valve, some valves can be equipped with an electric or pneumatic actuator as shown below. They attach directly to the milk stalk and are able to rotate it. The most common flange connection between the valve and the actuator is ISO 5211. The figure below shows an example of an ISO 5211 ready to connect to the actuator. Using the actuator, you can control your ball valve remotely or via the controller so that it can be used as an automatic switch. A spring-loaded ball valve, also called a spring, uses a spring to open / close the valve in the off position and an actuator to keep it open / closed. These are used for energy conservation applications or for safety reasons.
There are several different ways to control an actuator:
A 2-point controller (also called an open-closed or disconnected circuit (also called on / off) uses a control wire in addition to the power cords, and when the control cord is turned on, the valve is electrically If the control wire is without power, the valve closes (electrically or using a spring).
A 3-point control uses two control wires: one to turn the ball clockwise and the other to turn the ball clockwise. Depending on the application, the most appropriate control can be selected.
Some electrical actuators can also provide modulation control, which sets the ball valve between 0-100 open / closed.
Ball valve housing material
The most common enclosure materials are brass ball, stainless steel and PVC (PolyVinyl Chloride). The ball is usually made of chrome-plated steel, chrome-plated brass, stainless steel or PVC. Seats are often made of Teflon, but can also be made of other synthetic materials or metals.
Brass ball valve
Brass ball valve has the largest market share (Figure below). Rice is an alloy of copper and zinc and has good mechanical properties. Brass valves are used for water (drinking), gas, oil, air and many other media. Chloride solutions (eg seawater) may cause corrosion. Dezincification is a form of corrosion in which zinc is removed from an alloy. It reduces a porous structure with great mechanical strength. A brass chamber is suitable for air valves. View two-way brass ball valves or three-way brass ball valves.
Stainless steel ball valve
Stainless steel ball valve is used for corrosive and aggressive environments (Figure below). So they are often used in seawater, swimming pools, high temperature osmosis facilities and many chemicals. Most stainless steel is austenitic. Types 304 and 316 are the most common, 316 has the best corrosion resistance. 304 is called 18/8 because of 18% chromium and 8% nickel. 316 contains 18% chromium and 10% nickel (10/18). Stainless steel valves usually require more torque than brass or PVC valves. This should be considered when operating a stainless steel valve with a pneumatic or electric actuator. Use double-sided stainless steel ball valves or 3-way stainless steel ball valves.
PVC ball valve
PVC is often less expensive (except for ISO-top valves) and is widely used in irrigation, water supply and drainage or corrosive environments (Figure cdv). PVC stands for Polyvinyl Chloride. PVC is resistant to most saline solutions, acids, bases and organic solvents. PVC is not suitable for temperatures above 60 ° C and is also not resistant to aromatic hydrocarbons and chlorine. PVC is not as strong as brass or stainless steel, so PVC ball valves have a lower degree of pressure.
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