1, Overview At present, most of the globe valves are driven by handwheels or electric devices. When the handwheel is used to drive the globe valve to open or close, the action is slow, the labor intensity is high, and the degree of automation is low, which is not conducive to the integrated control of the valve and can easily lead to a safety accident caused by misoperation. The use of ordinary electric devices to open and close the globe valve, the agency is large, energy consumption, high cost, used in oil or chemical flammable and explosive fluid piping, inconvenient maintenance and the existence of hidden dangers. Therefore developed a new type of globe valve with a pilot valve. The valve can achieve the basic functions of ordinary globe valve, with the operation of flexible labor-saving, high precision, fast action, no corrosion, easy installation, long service life and easy maintenance. 2, the valve structure with the pilot valve globe valve manual control and electric control of two types. Manual stop valve with pilot ball valve (Figure 1) consists of valve body, disc, bonnet, guide sleeve, seal ring, spring and draft tube and other components. The valve is straight cylindrical, the bottom of the valve has a bottom hole, the lower part of the valve body has a sewage hole, the hole is equipped with a sealing nut. The diameter of the bottom hole of the valve is smaller than the inner diameter of the draft tube, and the upper part of the valve plate is provided with a pressure ring. The globe valve with pilot ball valve has no handwheel, valve stem and lifting nut, the guide block and the guide groove are changed to the guide sleeve, the disk valve is changed to the bowl-shaped valve disc, and the valve disc hole is opened at the bottom. The valve stem of the original stem hole to diversion hole, due to increased pressure ring, ring and the valve into a bowl, the upper chamber separated into upper chamber, outer chamber, lumen, in the upper and lower chamber The outside of the cavity is additionally provided with a draft tube and a stainless steel manual ball valve. A spring is added on the central part of the cover plate and the bottom of the valve disc. A pressure ring for compressing the sealing ring is added on the upper part of the valve disc. . For the electric control of the globe valve, only the pilot control of the manual valve with 3 ~ 5V DC motor drive can be. 1. Valve body 2. Guide sleeve 3. Sealing ring 4. Valve cover 5. Manual ball valve 6. Spring 7. Valve flap 8. Drain valve 9. Ball valve handle 10. Air duct 3, Working principle Known by the Bernoulli equation , When the fluid flow section changes, including the cross-section contraction and expansion, fluid flow resistance will arise, the corresponding fluid pressure will drop. With the pilot valve globe valve is a kind of pressure valve, the use of media pressure as the driving force, the use of pressure to promote the valve flap to complete the valve opening and closing, making the use of smaller valve opening and closing relatively large valve opening and closing . It is assumed that the initial state of the pilot valve is closed and the draft tube fails. As the valve flap and import at the bottom of the same time, the inlet pressure and valve pressure within the same, the valve flap under the weight and the spring force of the fall and valve seat closure, the valve is closed. When the pilot valve is opened, the valve flap communicates with the outlet and the water flows out. At this time, the water pressure in the upper part descends (both pressures are equal and P2 are both). Since there is a pressure difference between the inlet pressure P1 and the outlet pressure P2, Top up, open the valve. Since the diameter of the draft tube is larger than the diameter of the bottom hole, the pressure P1 of the inlet pipe is always larger than the pressure in the valve flap (counteracting the self-weight of the valve flap and the spring force) even in the presence of the bottom of the valve flap. Therefore, the valve flap Will fall, and keep all pass open, so as to ensure the maximum flux of fluid through. When the pilot valve is closed, the flap is disconnected from the outlet. After a certain period of time, the water flowing into the inlet is injected into the lumen of the valve flap through the bottom hole of the valve flap to balance the pressure of the valve flap with the gravity of the valve flap and the spring force. The valve flap closes with the valve seat again and the valve closes. When the water needs to be discharged, the water can be drained through the drain hole on the valve body to ensure that the water does not freeze and the valve does not rust. So cycle back and forth, you can achieve the valve closing and opening. 4, the performance test through the test, the pilot valve with a pilot valve open time 10 ~ 15s, off time 10 ~ 20s, the opening pressure of 0.01MPa, for the electric control valve, the use of pilot technology to 3 ~ 5V DC motor valve can be achieved Open and closed, the power consumption of about 2% of the ordinary electric valve. The valve has the advantages of compact structure, good sealing performance, easy operation and convenient maintenance. 5, the conclusion with the leading ball valve is a new type of globe valve. The core technology is to rationally determine the ratio of the diameter of the draft tube to the diameter of the bottom hole of the valve, which determines the valve action and energy consumption. If the ratio is much greater than 1, then the configuration of the pilot valve on the big, driving energy consumption will rise. If the ratio is equal to or less than 1, the valve can not be maintained open. At the same time, you can use to adjust the weight of the valve flap, the spring force and the bottom of the valve flap size to determine the valve opening pressure and opening and closing time.
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