Overhead valve of pulp digester

Abstract

The invention relates to an overhead valve of a pulp digester, which comprises a valve body, a valve seat, a valve stem, a ball, a bonnet, a seal part and a mounting part. The valve seat is fixedly mounted in a valve inlet passage and the ball is mounted in a floating manner. The overhead valve is characterized in that the valve seat is embedded in an annular vertical groove on the side wall of the inlet passage of the valve body to effectively prevent medium impurity entering the back of the valve seat, a seal pretension force regulator is arranged on the valve stem, the ball is pushed to besealed with the valve seat by regulating adjustable bolts of the seal pretention force regulator, and accordingly the sealing performance of the ball valve in a low-pressure state is improved. The overhead valve has the advantages of stability and reliability in running, excellent sealing performance and the like, and is suitable to be used as a control valve at a feed inlet of a batch digester in the paper making process.

Description

technical field [0001] The invention relates to the field of valves, in particular to a high-temperature wear-resistant ball valve. The invention is suitable for the control valve of the feed port of the batch cooker in the papermaking process. Background technique [0002] The digester is the main equipment in the papermaking process. Its function is to chemically react the raw materials under a certain temperature and pressure and chemical liquid to separate cellulose and form pulp. During the reaction process, high-temperature and high-pressure acidic and oily gas will be produced. The top valve of the digester is an important device to prevent the gas from leaking and pollute the environment and ensure the cooking effect. The top valve of the digester is vertically installed between the top of the digester and the raw material chute, and the raw material is wood chips, so the top valve of the digester must adopt a full-flow structure. The ball valve is the first choice...

AI Technical Summary

Problems solved by technology

Because the top valve of the digester is installed vertically, that is, the channel center line of the ball valve is perpendicular to the horizontal plane, and the ball valve must be strictly prevented from leaking gas in the digester when the ball valve is closed. Seat seal, the existing ball valve products, in order to prevent the ball and the seat from being stuck at high temperature, generally adopt floating seat, fixed ball structure or fixed seat, floating ball structure, but the pulp medium is very viscous and contains fine sand, For ball valves with a floating seat structure, impurities in the medium can easily enter the back of the valve seat and block the seat, resulting in poor reliability. However, for a ball valve with a floating ball structure, in a vertical installation state, due to the weight of the ball, the valve seat will be damaged when the digester is under low pressure. Compared with the ball seal, the pressure is low, easy to leak, and the sealing performance is poor

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