Jiangsu Bell Water Supply Pipeline Soft Sealed Electric Ball Valve

Jiangsu Bell Water Supply Pipeline Soft Sealed Electric Ball ValveThe sealing principle of a valve seat varies depending on its structure, and commonly used valve seat structures can be divided into two categories: fixed valve seat floating sphere and floating valve seat fixed sphere. When the fixed ball of the valve seat floats, under the action of fluid pressure, the ball undergoes displacement in the direction of fluid flow, causing it to seal more tightly with the valve seat behind the valve, that is, the specific pressure on the sealing surface increases, forming a single-sided seal. At the same time, the specific pressure on the sealing surface of the valve seat in front of the valve decreases correspondingly, which often does not guarantee sealing. When the floating ball of the valve seat is fixed, the fluid pressure cannot cause displacement of the ball, but the valve seat is pressed against the ball by the spring or fluid thrust, establishing a sealing pressure ratio.

Jiangsu Bell Water Supply Pipeline Soft Sealed Electric Ball Valvethe structure of

1Soft sealed valve seat

（1）Ordinary style

The characteristic of a regular valve seat is that the valve seat is tightly pressed against the sphere under the action of pre tension or fluid pressure, and the valve seat material undergoes elastic-plastic deformation to achieve sealing. Its sealing effect depends on the ability of the valve seat to compensate for the roundness of the sphere and the micro roughness of the surface under the action of fluid pressure or pre tension. Therefore, there must be a sufficiently large sealing pressure between the valve seat and the sphere.

（2）Elastic type

Elastic valve seat (Figure)2）By utilizing elastic components such as metal spring frames and springs, elastic deformation is generated under pre tension or fluid pressure to compensate for the impact of external conditions such as temperature differences, pressure, and wear on the sealing performance of the sphere.

（a）Single slope type（b）Double inclined double line type（c）VLinear self sealing type（d）Special style

（3）Spring combination type

The spring combination valve seat is a set of compression springs evenly distributed along the transverse section circumference of the valve channel, or only using the thrust of a disc spring, to always keep the valve seat tightly pressed against the ball and achieve a pre tightened state.

（a）Compressed spring type（b）Disc-shaped spring type

（4）Piston valve seat

The piston type valve seat relies on the pressure of the imported medium to generate sealing force. The valve seat is pushed to press the ball tightly, and the sealing ring undergoes elastic-plastic deformation to achieve sealing.

（a）Cut off the relief valve seat（b）Double motion valve seat（c）Double stage sealed valve seat

When the pressure inside the valve chamber of the cut-off relief valve seat abnormally rises to greater than the downstream end pressure, the pressure difference formed generates outward thrust, overcoming the spring force to detach the valve seat from the sphere, realizing the pressure in the valve chamber to be discharged downstream. Then, under the action of the spring, the valve seat re adheres to the sphere.

When the pressure in the middle chamber is greater than the outlet pressure, the double motion valve seat presses the ball tightly, and the sealing ring undergoes elastic-plastic deformation to achieve sealing. When the valve is in use, if the upstream seal accidentally fails and leaks, the downstream valve seat will achieve sealing.

The dual stage sealed valve seat adopts a rubber and plastic combination sealing structure for bearing large sealing forces. Rubber mainly plays a sealing role, while plastic plays a dual role of supporting and auxiliary sealing.

（5）Special structural formula

Special structural valve seat (Figure)5）There are internal or external adjustable, corrugated tube, grease sealed, double push, and combination types.

（a）Internally and externally adjustable（b）Bellows type（c）Grease sealed type（d）Double push type（e）Combination type

The internally adjustable valve seat is the sealing ratio between the valve seat and the ball, which is adjusted by the internally adjustable nut. Its advantage is that there are no outward leakage points. The external adjustable valve seat is the sealing ratio between the valve seat and the sphere, which is adjusted by pressing the wedge block with the external adjusting screw plug to cause displacement of the expansion sleeve.

The bellows valve seat is generally connected to the valve seat and guide sleeve by electron beam welding or argon arc welding. When designing, it should be ensured that the sealing center of the valve seat is smaller than the diameter of the corrugated pipe. This structure has the characteristics of reliable sealing, large elastic compensation range, and flexible three-dimensional space.

The grease sealed valve seat can increase sealing performance, reduce friction and wear of the valve seat, extend service life, and prevent accidents caused by valve seat damage or fire during the use of ball valves. A set of grease injection holes can be added to the valve seat. The grease seal only serves as an auxiliary sealing function or as a temporary emergency measure.

Double push valve seat is used whenNWhen the chamber is connected to the control pressure, the valve seat is tightly pressed against the ball and maintains a seal. whenMIndoor control pressureNWhen the chamber releases pressure to the outside, the valve seat retreats, causing it to disengage from the ball. The wear and friction between the valve seat and the ball, as well as the operating torque, are reduced, making it suitable for high and medium pressure large-diameter ball valves. The combination type is composed of a spring valve seat and a piston valve seat. The former plays the main sealing role, while the latter connects the control pressure and plays an auxiliary sealing role.