Suzhou Antway Valve Co., Ltd. (Jiangsu 215212) Cao Hui Li Xiaojuan In the presence of faults in the operation of the ball valve and caused its frequent replacement, introduced a new structural valve-one-disc valve, through the two valve In comparison, the advantages of using the disc valve in the worn material are pointed out, and the structural design of the disc valve is explained.
First, the use of ordinary valves in the system For solid particles and viscous medium, in order to avoid the accumulation of medium in the pipeline, control valves are generally used full-diameter valves, and valves with larger flow resistance such as globe valves should not be used. Only ball valves are available.
However, due to structural constraints, the ball valve is normally used on ordinary air-water pipes, but it has a lot of defects in the use of medium containing solid particles, mainly reflected in the following aspects.
Under the condition of large wear, the ball is generally coated with a hard alloy to increase its wear resistance to ensure the sealing performance of the valve. The sprayed thickness of the sprayed hard alloy is generally 0.3mm, and if the thickness is too thick, the bonding performance of the coating will be affected, but The thickness of the coating cannot meet the high sealing performance requirements under high temperature and high pressure for a long time.
Silicone and polysilicon are slightly sticky at high temperatures and have high hardness (about 70HRC). Because the medium and the sealing surface are in contact at the same position during each switching process, they easily stick to the surface of the sealing surface during valve switching. Scratch the sealing surface and affect the sealing performance of the valve.
The ball valve is easy to accumulate in the interior of the valve, which causes the valve to be interrupted. Under the action of the gradually increasing switching torque, the valve operating element quickly fails or causes damage in the short term.
The seal is statically loaded and cannot react or compensate for pressure and temperature fluctuations, affecting the sealing performance of the valve.
In order to overcome the above-mentioned defects of the ball valve, Suzhou Antway Valve Co., Ltd., on the basis of learning advanced foreign structures, has independently developed the eccentric wear-resistant disc valve after achieving continuous improvement, improvement and practice, and has achieved solid particle viscous medium. The high temperature, high pressure difference, high sealing performance requirements.
The disc valve is mainly composed of a valve body, a valve disc, a valve seat, a cylinder, a valve stem, a spring, a sleeve, a rocker, and the like (as shown). When the action is performed, the actuator pushes the rocker and drives the valve stem to rotate, so as to realize the valve switching. During the process, the valve disk rotates along with the valve stem and also has its own rotation. In the pressure and temperature fluctuations, each spring can play a compensating role, so as to ensure that the valve's external leakage and internal leakage are reduced to the design permit requirements.
Circle I plate valve structure plate valve is mainly for the ball valve in the course of the various problems encountered and re-developed a quick opening and closing valve. In order to solve the erosion of the sealing surface with high hardness solid particles, the valve plate and valve seat do not adopt the common substrate surface spraying and build-up welding methods in general valves, and all adopt the integral sintered cemented carbide, and use this material in bending resistance. Strength, compressive strength and other aspects also have very good performance. This not only solves the problem that the sealing surface is abraded by high-hardness solid particles, and the valve disk structure design requires self-rotation during the switching process, so that the sealing position is not unique during the switching, so that the valve disk and the valve seat have self-grinding during the switching process. The effect is that the longer the usage time, the better the sealing performance. A purge port is opened at the bottom of the cylinder, and purging is performed regularly according to the design requirements to avoid the normal operation of the valve due to blockage, crystallization and deterioration of the material. Each spring seal is designed to be spring-loaded to provide the necessary compensation for operating conditions fluctuations.
The main technical parameters of the disc valve (in the case of silicon chemical industry low temperature room temperature carbon steel valve body) medium characteristics: solid, hardness> 65, particle size 0.0280.125mm valve requirements banned grease working temperature: SD type single valve disc valve closed static pressure Acts on the back of the valve disc. At this point, the media pressure acts as a self-sealing. It is suitable for working conditions where the reverse pressure is low and the valve is installed from bottom to top (as shown).
Type LD double valve disc but no valve seat on the inlet side, this model has no special requirements for the valve installation position, but requires the material must be entered from the valveless end, and is not suitable for applications where two-way sealing is not required (such as the LD double valve disc Type LB valve disc with locking device, these valves need to enter the material from the side with the valve plate, apply to the pressure difference is not large, but also need to be able to achieve two-way sealing of the occasion (as shown).
DD double valve disc bidirectionally sealed, bi-directional flow, this form has no special requirements for the installation direction, position and pressure difference, the most widely used (as shown).
For all valves higher than 400C, the inner wall (all the parts contacting the medium) is used to spray-weld the hard alloy to improve its hardness and wear resistance, and the site reflects good use.
Third, the main part of the design and calculation of the disc valve body wall minimum wall thickness using ASMEB16.34 Appendix wall thickness calculation formula to calculate, or according to BS5351 specified shell wall thickness selected.
2 Sealing specific pressure According to the formula 0GM general mechanical stem stress analysis Bracket deformation displacement analysis b - sealing surface design width, in mm; Pn - valve nominal pressure, in MPa. F - force acting on the valve disc The unit is N; A - the contact area of ​​the valve disc and the valve seat, the unit is mm2. The actual design should meet the valve stem strength check calculation ul - sealing surface friction factor.
1 - The total height of packing, in mm; "2 - valve stem and packing friction factor.
Twist stress can be obtained by consulting the relevant design manual.
Valve stem and valve bracket force conditions and deformation displacement check Due to the complex force conditions of the valve stem and the bracket, it is affected by the pressure fluctuation of the gas source, the impact of the actuator, the frequency and temperature of the valve switch, the temperature, and whether there is local jam within the valve. And many other factors. Therefore, the finite element analysis and calculation of the force and deformation displacement of these two parts are shown as shown in the figure.
Valve body, spring, spring seat, stem material are shown in the table below.
Material Code Table Name Material Code Valve Body Spring Spring Valve Shaft Disc Valve Seat Spring Block Handle Packing Gland Filler Graphite Gasket 304+ Flexible Graphite 316+ Flexible Graphite Applicable Temperature/C Disk Valve Actuated by sliding disc spool A fast opening and closing valve. Designed specifically for materials with wear and erosion characteristics, it can operate normally for long periods of time in harsh conditions. The unique hard sealing surface has a self-grinding effect, which makes it continuously improve the sealing during the application of the abrasion and erosion materials, and the life is several times longer than other valves.
The wear-resistant disc valve produced by Suzhou Antway Valve Co., Ltd. has been widely used in the manufacturing process of organic silicon, polysilicon and non-ferrous metals, and it has been widely praised by users and has a wide range of application prospects.
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