CN205173511U - A kind of ultra-low temperature butterfly valve - Google Patents

Abstract

The utility model discloses an ultra-low temperature butterfly valve, which comprises a valve body, a valve stem, a butterfly plate and a worm gear device. The valve body is provided with a fluid passage, and the valve stem and the butterfly plate are arranged in the valve body; the butterfly plate passes through The pin is fixedly connected to the valve stem; the top of the valve stem is connected to the worm gear; a packing set is arranged between the valve stem and the valve body; a packing gasket is arranged under the packing set; the packing set includes flexible graphite packing and Graphite packing; above the packing group, a packing gland and a packing gland are sequentially arranged; the packing gland is fixedly connected to the valve body through stud bolts; the worm gear device includes a hand wheel; the outer surface of the hand wheel Features non-slip rubber ribs. The utility model can still maintain good sealing performance in an ultra-low temperature environment, and has a long service life.

Description

A kind of ultra-low temperature butterfly valve

technical field

The utility model relates to the field of control in fluid delivery systems, in particular to an ultra-low temperature butterfly valve in the field of valve control.

Background technique

Liquefied natural gas (LNG) is a clean and efficient energy source. Against the background of increasingly prominent environmental problems, natural gas is becoming more and more popular as a clean energy source. Due to this trend, natural gas application technology has also developed rapidly, especially in the field of transportation where liquefied natural gas is often used due to its high efficiency. In recent years, my country has also paid more and more attention to the introduction of LNG. A large number of LNG receiving stations have been arranged along the coast. In the entire process of LNG from production to consumption, a large number of valves are needed. This type of valve is one of the ultra-low temperature valves. As the fastest growing butterfly valve in recent years, it is becoming more and more important in the application of LNG. However, there is still a blank for ultra-low temperature butterfly valves for LNG in China. For this reason, it is imperative to develop ultra-low temperature butterfly valves for LNG.

Contents of the invention

The problem to be solved by the utility model is to propose an improvement scheme or a replacement scheme for the above-mentioned shortcomings in the prior art, especially an ultra-low temperature butterfly valve.

In order to solve the above problems, the solution adopted by the utility model is as follows: A kind of ultra-low temperature butterfly valve, including a valve body, a valve stem, a butterfly plate and a worm gear device, is characterized in that a fluid passage is provided on the valve body, and the valve stem and The butterfly plate is set in the valve body; the butterfly plate is fixedly connected to the valve stem through a pin; the top of the valve stem is connected to the worm gear device; a packing group is arranged between the valve stem and the valve body; Packing gasket; the packing group includes flexible graphite packing and graphite packing; the packing gland and packing gland are arranged in sequence above the packing group; the packing gland is fixedly connected with the valve body through stud bolts; the The worm gear device includes a hand wheel; the outer surface of the hand wheel is provided with anti-slip rubber convex strips.

This series of valves is mainly aimed at LNG working medium, with a nominal pressure of 150-600lb (1lb=0.454kg), a design operating temperature of -196°C, and a nominal diameter of DN200-DN1000. LNG ultra-low temperature butterfly valve has connection methods such as flange, lug, wafer and butt welding according to the requirements of the working conditions. However, due to the ignitability and explosiveness of LNG, the safety and reliability of the LNG cryogenic valves for the system equipment are higher than those of ordinary cryogenic valves, and they are required to have a fire-resistant design. Therefore, the main pipeline of LNG ultra-low temperature butterfly valve mostly adopts butt welding structure design. The LNG ultra-low temperature butterfly valve with butt welding structure mainly includes a valve body with an inspection hole, an inspection bonnet, a butterfly plate, a valve stem, and an extension of the packing gland; The running of time will inevitably lead to the wear of the sealing ring, followed by the decline of the sealing performance of the valve, so the maintenance of the butterfly valve with butt welding connection is a problem that must be solved. There are two methods for traditional butterfly valve maintenance, one is to directly remove the entire valve body from the pipeline, and then take it out from the side to replace the sealing mechanism; the other is to install a valve cover on the top of the valve, during maintenance, Take out the entire valve cover together with the butterfly plate, valve stem and other mechanisms from the valve body to realize online replacement of the butterfly plate seal. Obviously, if the butt welding structure is adopted, the former valve can only be repaired by cutting the pipeline, and its cost and effect are poor; while the latter type of valve is also more difficult to maintain, and it is not easy to ensure accuracy. Therefore, when developing the LNG ultra-low temperature butterfly valve, an inspection hole is set on the valve body, which can realize that it is not necessary to disassemble the entire valve body from the fluid pipeline, and it is not necessary to disassemble all the parts connected to the valve stem and the valve disc. The valve seat on the valve body and the seal of the valve disc can be replaced, making online maintenance of the valve more convenient and faster.

The valve seat on the sealing auxiliary valve body is fixed on the valve body by the pressure ring and screws embedded in the valve body groove. The butterfly plate is mainly composed of the butterfly plate body, pressure plate and seals. The seal between the valve seat and the butterfly plate The parts form a sealing pair. Since the temperature of LNG under normal pressure is -162°C, the design of the sealing pair adopts the composite structure of metal and non-metal materials.

Further, according to the ultra-low temperature butterfly valve described in the above design scheme, a spacer ring is arranged in the middle of the packing group, and the spacer ring divides the packing group into upper and lower parts.

Further, according to the ultra-low temperature butterfly valve described in the above-mentioned design scheme, a sealing ring is provided at the closure between the valve body and the butterfly plate; a pressure plate is provided outside the sealing ring; the pressure plate is fixedly connected to the valve body by hexagon socket head cap screws.

Further, according to the ultra-low temperature butterfly valve described in the above design scheme, a valve disc retainer matching the sealing ring and the pressure plate is provided at the closed position between the butterfly plate and the valve body; the valve disc retainer is fixedly connected to the butterfly plate by hexagon socket head cap screws.

Technical Features In addition to following the design principles of general valves, the design of cryogenic valves also has some special requirements. First of all, it should be considered that the main parts of the valve should be able to withstand the stress caused by long-lasting or instantaneous large temperature changes; and the force of various loads under alternating pressure and temperature should not appear obvious elastic-plastic deformation . In addition to the conventional strength calculation of the valve body and bonnet during design, finite element stress analysis and anti-vibration analysis should also be used to ensure the reliability of the valve product, so LNG ultra-low temperature butterfly valves are made of low-carbon austenitic stainless steel (CF3 , CF3M) as the main material, its low temperature resistance, pressure resistance, wear resistance, corrosion resistance, weldability, strength, impact toughness, relative elongation and organizational stability are superior to other materials. Secondly, in the case of meeting the strength and rigidity requirements, the weight of the parts should be small to reduce the heat conduction loss. Thirdly, due to the temperature stress on the valve body and the additional stress of expansion and contraction of the connecting pipe under low temperature conditions, in order to prevent brittle damage caused by stress concentration at low temperature, sharp corners and grooves in the shell should be avoided as much as possible. .

Further, according to the ultra-low temperature butterfly valve described in the above design scheme, the sealing ring is made of polychlorotrifluoroethylene.

Further, according to the ultra-low temperature butterfly valve described in the above design scheme, a sealing gasket is provided between the valve flap pressure ring and the butterfly plate.

Further, according to the ultra-low temperature butterfly valve described in the above design scheme, the sealing gasket is made of polychlorotrifluoroethylene.

Further, according to the ultra-low temperature butterfly valve described in the above design scheme, an inspection hole is provided on the valve body on the side where the valve stem is installed, and an inspection upper cover that is detachably sealed with the valve body is installed at the location of the inspection hole.

Further, according to the ultra-low temperature butterfly valve described in the above design scheme, the bottom of the valve body is provided with a bottom cover; the bottom cover is fixedly connected with the valve body through hexagon socket head screws; the bottom cover is provided with an adjustment pad; the valve stem is set on the conditioning pad.

Further, according to the ultra-low temperature butterfly valve described in the above design scheme, a valve stem bushing is provided between the bottom end of the valve stem and the valve body; a split ring is arranged at the lower end of the valve stem bushing.

The length of the extension part of the stem packing gland of the ultra-low temperature butterfly valve should be selected according to the fluid medium and whether the cold box is used to design the optimal length to improve the performance of the low temperature valve in the working environment.

The technical effect of the utility model is as follows: the ultra-low temperature butterfly valve of the utility model is extremely careful in its detailed design and production precision control due to its low temperature working condition and the danger of its medium. In addition, due to the increasing requirements for environmental issues, safety measures and energy saving in recent years, the utility model meets the low emission standard technology. Compared with the existing butterfly valve, the ultra-low temperature butterfly valve of the utility model has an epoch-making improvement in sealing performance. A packing group is arranged between the valve stem and the valve body. The selected packing group is composed of flexible graphite packing and graphite packing, so that the sealing performance is improved. Stronger and more stable, and a spacer ring is set in the middle of the packing group to divide the packing group into upper and lower parts, further improving its sealing performance. The structure of the pressure plate and the valve body sandwiching the sealing ring is adopted at the closed sealing place between the valve body and the butterfly plate, and the valve disc pressure ring on the upper butterfly plate is used to further improve the sealing performance. And the sealing ring and gasket are made of polytrifluorochloroethylene, which can ensure the sealing performance even at ultra-low temperature. And the anti-slip rubber convex design on the handwheel makes the handwheel more convenient to use.

Description of drawings

Figure 1 is a schematic diagram of the structure of a cryogenic butterfly valve.

Figure 2 is a schematic diagram of the closed structure of the butterfly plate and the valve body.

Among them, 1-worm gear device, 2-packing gland, 3-packing gland, 4-packing group, 5-packing washer, 6-valve body, 7-valve stem, 8-pin, 9-butterfly plate, 10- Stem bushing, 11-split ring, 12-adjusting pad, 13-bottom cover, 14-sealing ring, 15-pressure plate, 16-sealing pad, 17-disc pressure ring.

detailed description

Below in conjunction with accompanying drawing, the utility model is described in further detail.

An ultra-low temperature butterfly valve, including a valve body, a valve stem, a butterfly plate and a worm gear device, the valve body is provided with a fluid passage, the valve stem and the butterfly plate are arranged in the valve body; the butterfly plate is fixed to the valve stem by a pin connection; the top of the valve stem is connected to the worm gear device; a packing set is provided between the valve stem and the valve body; a packing gasket is provided under the packing set; the packing set includes flexible graphite packing and graphite packing; A packing gland and a packing gland are sequentially provided above the packing group; the packing gland is fixedly connected to the valve body through stud bolts; the worm gear device includes a hand wheel; the outer surface of the hand wheel is provided with a non-slip rubber protrusion There is a spacer ring in the middle of the packing group, and the spacer ring divides the packing group into upper and lower parts, and a sealing ring is provided at the closure between the valve body and the butterfly plate; a pressure plate is provided on the outside of the sealing ring; The pressure plate is fixedly connected with the valve body through the hexagon socket head cap screws, and the valve disc pressure ring matching the sealing ring and the pressure plate is provided at the closed part of the butterfly plate and the valve body; the valve disc pressure ring is fixedly connected with the butterfly plate through the hexagon socket head cap screws, The sealing ring is made of polychlorotrifluoroethylene, and a sealing gasket is arranged between the disc pressure ring and the butterfly plate, and the sealing gasket is made of polychlorotrifluoroethylene.

Claims (10)

1. a ultralow temperature butterfly valve, comprises valve body, valve rod, butterfly plate and gear, it is characterized in that, described valve body is provided with fluid passage, and described valve rod and butterfly plate are located in valve body; Described butterfly plate is fixedly connected with valve rod by pin; Described valve stem top is connected with gear; Filler group is provided with between described valve rod and valve body; Filler packing ring is provided with below described filler group; Described filler group comprises flexible graphite packing and graphite packing filling; Filler pressing sleeve and Gland is provided with successively above described filler group; Described Gland is fixedly connected with valve body by stud bolt; Described gear comprises handwheel; Described handwheel outer surface is provided with anti-slip rubber raised line.

2. ultralow temperature butterfly valve according to claim 1, is characterized in that, is provided with spacer ring in the middle of described filler group, filler component cuts as upper and lower two-part by described spacer ring.

3. ultralow temperature butterfly valve according to claim 1, it is characterized in that, described valve body and the butterfly plate place of closing are provided with seal ring; Pressing plate is provided with outside described seal ring; Described pressing plate is fixedly connected with valve body by socket head screw.

4. ultralow temperature butterfly valve according to claim 3, it is characterized in that, described butterfly plate and the valve body place of closing are provided with the flap trim ring mated with seal ring and pressing plate; Described flap trim ring is fixedly connected with butterfly plate by socket head screw.

5. ultralow temperature butterfly valve according to claim 3, it is characterized in that, described seal ring is that polychlorotrifluoroethylene is made.

6. ultralow temperature butterfly valve according to claim 4, is characterized in that, be provided with sealing gasket between described flap trim ring and butterfly plate.

7. ultralow temperature butterfly valve according to claim 6, it is characterized in that, described sealing gasket is that polychlorotrifluoroethylene is made.

8. arbitrary ultralow temperature butterfly valve according to claim 1-7, is characterized in that, described valve body is provided with access opening in the side of installing stem position, is provided with the maintenance upper cover be connected with valve body detachable-type sealed in the position of access opening.

9. ultralow temperature butterfly valve according to claim 8, it is characterized in that, described body base is provided with bottom; Described bottom is fixedly connected with valve body by socket head screw; Described bottom is provided with spacer; Described valve rod is arranged on spacer.

10. ultralow temperature butterfly valve according to claim 9, is characterized in that, be provided with valve lever bushing between described valve rod bottom and valve body; Described valve lever bushing lower end is provided with trip ring.