The ball of floating ball valve is floating. Under the action of medium pressure, the ball can produce certain displacement and press tightly on the sealing surface at the outlet end to ensure the sealing at the outlet end. Structure 1. The valve stem should be inverted, anti-blowout structure. The valve stem of the valve should not be limited by the packing gland fasteners. To be precise, the valve stem will not be separated from the valve due to the loosening of the valve stem sealing fasteners when the valve is under pressure. 2. Anti-static structure. It consists of a stainless steel ball and a spring. One group is placed in the hole at the end of the valve stem, keeping in contact with the ball; the other group is placed on the cylinder of the valve stem, keeping in contact with the valve body, so that the possible static electricity is guided away from the valve body. 3. Fire-safe structural design. When the sealing seat is burned, the main and auxiliary valve bodies should be in contact with the sphere and maintain a certain degree of sealing. The connecting surfaces of the main and auxiliary valve bodies shall adopt gaskets with fire safety functions, such as metal wound gaskets. At the packing seal of the valve stem, when the packing (PTFE) is burned, there should be a graphite ring to prevent the medium from leaking out. 4. There should be a limit mechanism to accurately limit the ball to be in the "open" or "close" position. 5. There should be a platform for installing pneumatic, electric and worm gear actuator brackets on the valve body. Sealing Principle The opening and closing part of the floating ball valve is a sphere with a through hole equal to the diameter of the pipe in the middle. The inlet and outlet ends are each equipped with a sealing seat made of PTFE, and are contained in a metal valve body. When the through hole in the sphere coincides with the pipeline channel, the valve is in the open state; when the through hole in the sphere is perpendicular to the pipeline channel, the valve is in the closed state. When the ball valve is in the closed position, the medium pressure at the inlet end acts on the ball, generating a force to push the ball, making the ball press the sealing seat at the outlet end tightly, and a contact stress is generated on the tapered surface of the sealing seat to form a contact zone. The force per unit area of the contact zone is called the working specific pressure of the valve seal. When this specific pressure is greater than the necessary specific pressure for sealing, the valve is effectively sealed. This kind of sealing method that does not rely on external force is sealed by medium pressure, which is called medium self-sealing.

Vacuum ball valve refers to a ball valve whose working pressure is lower than the standard atmospheric pressure and forms a certain vacuum. Its working principle is similar to that of a vacuum butterfly valve, and the valve is opened and closed by rotating the ball fixed on the rotating shaft by 90°. Because the valve body and stem are made of stainless steel in its structure, and the sealing materials such as the valve seat and packing are all polytetrafluoroethylene, it is suitable for working conditions where the medium is air, water, steam, acid, alkali, etc. Features 1. It adopts 1/4 rotary pneumatic or electric actuator, which works smoothly, and the valve switch has electric signal output, which can be used both by hand and by electricity; 2. It not only has simple structure and good sealing performance, but also has small installation size, small driving torque, simple operation, and easy to realize rapid opening and closing; 3. It can be used in a high vacuum state or a low pressure system to achieve the advantages of both positive and negative pressure. Connection Forms (1) Flange connection: This is the most commonly used connection form in valves. According to the shape of the joint surface, it can be divided into the following types: ① Smooth type: used for valves with low pressure, it is more convenient to process; ② Concave-convex type: the working pressure is relatively high, and medium-hard gaskets can be used; ③ Tongue and groove type: gaskets with large plastic deformation can be used, which are widely used in corrosive media and have good sealing effect; ④ Trapezoidal groove type: use oval metal ring as gasket; ⑤ Lens type: The gasket is in the shape of a lens and made of metal; ⑥ O-ring type: It is a relatively new flange connection form developed with the emergence of various rubber O-rings, and its sealing effect is more reliable than ordinary flat washers. (2) Threaded connection: This is a simple connection method, often used in small valves. It is divided into two situations: ① Direct sealing: The internal and external threads directly play a sealing role. ② Indirect sealing: The power of thread tightening is transmitted to the gasket between the two planes, so that the gasket acts as a seal.

Wedge gate valve is a kind of gate valve. It is named for its sealing surface and vertical center line at a certain angle, that is, the two sealing surfaces are wedge-shaped. Wedge gate valves are divided into rising stem wedge gate valves and non-rising stem wedge gate valves. In the rising stem wedge gate valve, the stem moves up and down, and the stem nut is fixed. The non-rising stem gate valve has a fixed stem, and the disc moves up and down to complete the opening and closing. The driving methods include: electric, pneumatic, manual, gas-hydraulic, etc., and the connection methods adopt flange type, welding type, and wafer type. Working Principle The opening and closing part of the wedge gate valve is the wedge, and the movement direction of the gate is perpendicular to the direction of the fluid. Wedge gate valve can only be fully opened and fully closed, not suitable for regulation and throttling. Wedge gate valve generally completes the opening and closing of the valve by moving the valve stem up and down with the rotating hand wheel. Structural Characteristics 1. Compact structure, reasonable design, light and flexible, good rigidity of the valve, smooth passage, small flow coefficient; 2. The sealing surface is made of stainless steel and hard alloy, which has a long service life; 3. With flexible graphite packing, the seal is reliable. Application Range Wedge gate valve is widely used in electric power, petroleum, chemical industry, metallurgy, mining, sewage treatment and other industrial fields, especially in the ash removal and coal washing plant equipment of power stations.

Resilient seated sealing gate valve utilizes the compensation effect of the elastic deformation of the overall rubber covering of the gate to achieve a good sealing effect, and overcomes the problems of poor sealing, water leakage and rust in general gate valves. Resilient seated sealing gate valve can be widely used in tap water, sewage, construction, petroleum, chemical industry, food, medicine, textile, electric power, shipbuilding, metallurgy, energy system and other working conditions, and it is used as a shut-off device on the fluid pipeline. Features of Resilient Seated Sealing Gate Valve: 1. Flat-bottom valve seat, no dirt accumulation, more reliable sealing. 2. The wedge is covered with nitrile rubber as a whole, and the internal parts of the valve are made of corrosion-resistant stainless steel and copper alloy materials, which can be used in the sewage system and adapt to the harsh working environment. 3. Small size, light weight, easy to install and maintain. 4. The valve stem is sealed with three O-rings, which greatly reduces the friction resistance when switching, and the switch is light and water-proof. 5. The valve body is made of precision casting, and the precise geometric dimensions make the valve body tight without any finishing work. 6. The copper nut and the elastic wedge are embedded in the joint, so that the two are closely integrated into one body, and there is no loosening or damage caused by the vibration caused by the water flow. 7. The valve body is coated with powder epoxy resin, which can prevent corrosion and rust of the valve body and can be used in sewage system. 8. The inside of the valve body is coated with non-toxic epoxy resin, and the inner and outer surfaces of the valve are completely covered with rubber, which will not rust or corrode, and can be used for raw drinking.

Bellow seals globe valve is a valve used to control the flow rate. Bellow seals globe valve adopts a bellow structure inside, and the lower end of the stainless steel bellow is welded on the valve stem to prevent the process fluid from corroding the valve stem. It eliminates the disadvantages of fast aging and easy leakage of ordinary valve stem packing seals, not only improves the energy efficiency, increases the safety of production equipment, reduces maintenance costs and frequent maintenance, but also provides a clean and safe working environment. It is suitable for pipelines of steam, flammable, explosive, heat transfer oil, high-purity, toxic and other media. Advantages: 1. Double sealing design (bellow + packing), if the bellow fails, the stem packing will also avoid leakage; 2. It is not easy to leak and meets international sealing standards; 3. There is no fluid loss, reducing energy loss and improving the safety of factory equipment; 4. Good anti-friction performance, long service life, reduced maintenance times, and reduced operating costs; 5. Strong and durable bellow seals design ensures zero leakage of the valve stem and provides maintenance-free conditions; 6. Intuitive indication of valve stem lifting position.

The flat gate valve is a sliding valve whose closing part is a parallel wedge. The closing part can be a single gate or a double gate with a spreading mechanism in between. Flat gate valves can be divided into flat gate valves with diversion holes and flat gate valves without diversion holes according to the gate structure. Balanced plate valves with diversion holes are used for pipelines transporting oil and natural gas. For pipelines that do not require sweepers, flat gate valves without diversion holes can be used. Features of Flat Gate Valve 1. Small flow resistance. Since the wedge slides on the two valve seat surfaces, the flat gate valve is also suitable for fluids with suspended particles. 2. It has a double block and bleed function. 3. Fireproof design. When the O-ring and PTFE are burned, under the action of fluid pressure, the wedge and the retainer, the retainer and the valve body form a metal seal, thereby isolating the fluid. In addition, the middle flange gasket and packing are made of graphite and metal materials to prevent external leakage. 4. Self-releasing function: When the pressure in the middle cavity is high, the fixer will be pressed back under the action of the fluid in the middle cavity, so as to avoid accidents caused by excessive pressure in the middle cavity.