As a kind of gate valve, a carbon steel gate valve can be divided into wedge gate valves and parallel gate valves according to the sealing surface. Wedge gate valves can be divided into single wedge gate valves, double wedge gate valves and elastic wedge gate valves. Parallel wedge gate valves can be divided into single wedge gate valves and double wedge gate valves. According to the thread position of the valve stem, a gate valve can be divided into two types rising stem gate valves and non-rising stem gate valves.
Working principles When the carbon steel gate valve is closed, the sealing surface can be sealed only by the medium pressure, that is, relying on the medium pressure to press the sealing surface of the wedge to the valve seat on the other side to ensure the sealing of the sealing surface, which is self-sealing. Most gate valves are forcibly sealed, that is, when the valve is closed, the wedge must be forced against the valve seat by an external force to ensure the sealing of the sealing surface. The wedge of the gate valve moves linearly with the valve stem, which is called a rising stem gate valve. Usually, there are trapezoidal threads on the rising stem. Through the nut at the top of the valve and the guide groove on the valve body, the rotary motion is changed into a linear motion, that is, the operating torque is changed into an operating thrust.
Advantages and disadvantages of gate valves Advantages of gate valves 1. Light weights: The body is made from good ductile iron, which is about 20% to 30% lighter than the traditional gate valve and is easy to install and maintain. 2. Flat-bottomed valve seat: foreign objects such as stones, wood blocks, cement, iron filings and sundries often accumulate in the groove at the bottom of the traditional valve after the pipe is washed by water, resulting in the valve not being able to be closed and leaking. The bottom of the elastic valve gate valve adopts the same flat bottom as the water pipe, which is not easy to cause debris accumulation and makes the fluid flow unobstructed. 3. Overall rubber coating: carbon steel wedges adopt high-quality rubber for overall internal and external rubber coating. The first-class rubber vulcanization technology in Europe enables the vulcanized wedge to have accurate geometric dimensions, and the rubber and ductile graphite cast wedge are firmly attached. 4. Precision casting valve bodies: The valve body adopts precision casting, and the precise geometric dimensions make the internal of the valve body not processed to ensure the sealing of the valve. 5. The fluid resistance is small, and the sealing surface is less scoured and eroded by the medium. 6. Opening and closing are more labor-saving. 7. The flow direction of the medium is not restricted, without disturbing the flow or reducing the pressure. 8. Simple shapes, short length, good manufacturing process and wide application
Disadvantages 1. Scouring and scratches easily happen between the sealing surfaces for a carbon steel gate valve, and it is difficult to maintain. 2. The overall size is large; a certain space is required for opening, and the opening and closing time is long. 3. The structure is more complicated.