Bellows seal valve

An improved bellows valve is disclosed having a relatively long bellows attached at one end to the valve control stem and at its other end to a recessed bellows mounting in the valve bonnet. The recessed attachment permits the use of a relatively long bellows with a valve bonnet of minimal size and mass and permits a wide valve opening with a relatively small valve port. Such a small valve port requires a low closing force for the stem and the use of a wide opening resists clogging. An anti-torque member connected between the valve bonnet and the valve stem prevents stem rotation to isolate the bellows from undesirble rotation during the axial stem and bellows movement. There are a wide variety of valves where the sealing means between the stem and the adjacent valve body is a bellows element. The bellows is attached at one end to the valve body and at the other end to the valve stem. The flexible bellows structure permits the necessary stem movement as the bellows is extended and compressed during valve closing and opening. It has been found desirable in valves of this type to use relatively small valve ports with a substantial valve stem movement to provide for maximum control fluid flow. Such smaller ports permit lower valve closing forces and thus smaller and more easily manipulated actuators. At the same time, the full valve opening resists clogging. A disadvantage of prior valves using long bellows has been the relatively large valve body and stem structure required to mount the elongated bellows. The improved valve of the present invention has a recessed mounting structure for the upper end of the bellows permitting a substantial reduction in the valve body size and a corresponding shortening of the valve stem. In addition, the improved valve includes a novel and positive acting anti-torque control to prevent bellows twisting and to therefore insure a long bellows life. It will be seen that an improved bellows valve has been provided which obtains significant stem movement by utilizing an elongated bellows having a recessed bellows attachment. This bellows permits significant stem movement to obtain the related advantages of a small valve port and a wide port opening for preventing clogging of the controlled fluid flow at the valve port. The improved hand wheel or actuator mounting also provides for a relatively easy axial stem motion without stem rotation to insure a long bellows life.

                                                                                                      Shanghai Remy Valve Manufacturing Co., Ltd

2012-01-17 07:08