Design and Experiment of a New Type of Rotary Valve Group for Reciprocating Pumps WANG Ke-Li 1, CHEN Li 2, ZI Ji-Zhi 2 (I. Chongqing Medical Design Institute, Chongqing 442; 2. Chongqing Pump Factory Co., Ltd., Chongqing 400033) On the basis of adopting solutions such as adjusting the physical and chemical properties of the valve block material and hardness, and improving the structure of the valve group, the valve disc that can normally only open and close in the axial direction is rotated by using a rotary wing valve to change the sealing surface. The initial conditions for fatigue failure in the area due to the impulse stress 'prolong the service life of the valve block.
The service life of the reciprocating pump valve group directly affects the continuous operation cycle of the pump unit. The general feature of damage to the valve group is the pit or groove on the sealing surface (such as the chamber 1), but it is used in the petrochemical industry to transport methanol and other high-pressure and high-permeability toxic In the medium and hydrometallurgical industries, reciprocating pump units that deliver high-abrasive ore slurry such as nickel sulfate sometimes have partial grooves in the sealing surfaces of the valve disc and the valve seat, and the concave or groove of the valve group sealing surface will cause Material flow, performance drops steeply and fails.
The destruction mechanism of the partial groove phenomenon on the sealing surface of the valve group is more complicated. It may be that the high pressure overflow of the valve gap forms local scour or cavitation damage on the sealing surface, or it may be the high hardness of the same particles stuck on the sealing surface. The valve plate and the valve seat continuously hit the sealing surface to form an abrasion or impact damage. Solve the problem of service life of reciprocating pump valve group generally through two ways: First, adjust the valve block material and hardness and other physical and chemical properties, improve its corrosion resistance and wear resistance; second is to optimize the valve group structure, by adjusting the valve plate lift Limit the maximum valve gap flow rate or meet the valve group to improve the valve structure without impact conditions. However, the above solution is often limited by the pump structure and operating conditions, and its improvement effect has an uncertainty of 1W1. In particular, the effect of the partial groove phenomenon on the sealing surface is often not obvious.
After analysis, the formation of local grooves in the sealing surface of the valve group inevitably undergoes a point-to-face expansion process. Based on the above-mentioned solution, it can be considered that the valve disk, which normally can only be moved up and down in the axial direction, can generate rotational motion. By constantly displacing the valve disk and the valve seat in the circumferential direction, the local area of ​​the sealing surface can be changed due to the pulse. The stress produces initial conditions of fatigue failure, thereby preventing or slowing the local groove phenomenon of the sealing surface, prolonging the service life of the reciprocating pump valve group.
Valve group with damaged sealing surface 1 Rotary valve group Working principle and structure 1.1 Rotary valve group Principle of operation The disc valve of a reciprocating pump is generally guided by guide ribs to open and close the valve discs. When the pressure in the lower part of the valve disc is sufficient to overcome The valve opens when the valve mass and spring load. In contrast, when the valve disc is closed and closed, it must form an effective seal with the valve seat to prevent back flow of the medium and reduce pressure loss. Guiding ribs ensure that the flow resistance is as small as possible. Usually, only the proper guide length and the clearance between the guide ribs and the valve seat are taken into account in the design. This ensures that the valve disk can be opened and closed smoothly, preventing jamming. Zhu Hua, Battle Long pine. Reciprocating pump. Beijing: Mechanical T. Industry Press, 1992. Yan Guojun, Zhao Junming, Dong Yong. Research on Motion Law of Reciprocating Pump Valves . China Helmut Schulz. Pump principle, calculation and structure. Beijing: Machinery 7: Industry Press, 1991.
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