上海方工阀门生产的闸阀阀体的结构决定与阀体与管道、阀体与阀盖的连接、就制造方法而言，有铸造、锻造、锻焊、铸焊以及管板焊接等几种。锻造阀体已向大口径方向发展，而铸造阀体逐渐向小口径发展。任何一种闸阀阀体即可锻造，也可铸造，应根据用户要求以及制造厂拥有的制造手段而定。

　　FGV闸阀阀体的流道可分为，全通径式和缩径式两种。流道孔径与阀门公称通经，基本相同的为全通径式;流通孔径比阀门公称通经小的称为缩径式。缩径形状有均匀缩径和费均匀缩径两种。流道呈锥管形的即是一种非均匀缩径，这类阀门入口端的孔径基本上与公称通径相同，然后逐渐缩小，至阀座处缩小到*小。

　　采用缩径式流道(无论是锥管形非均匀缩径或均匀缩径)，其优点是同一规格的阀门，可减少闸板的尺寸、启闭力与力矩;缺点是流阻增加，压降和能耗增大，所以缩孔不宜太大。对锥管形缩径来说，阀座的内径与公称通径之比，通常取0.8～0.95。公称通径小于250mm的缩径阀门，其阀座内径一般比公称通径降低一档;公称通径等于或大于300mm的缩径阀门，其阀座内径一般比公称通径降低二档。

　　Shanghai valve valve body work on the structure of the body and pipe, valve and the connection with the bonnet and manufacturing methods, casting, forging, forge welding, ZhuHan and tube plate welding etc. Forging body has to large diameter direction, and gradually cast body small development. Any kind of valve body can forging, also can cast, should according to the requirements of users and manufacturers owned manufacturing methods.

　　FGV gate valve can be divided into the passage, full-bore type and non-reducing type two kinds. Nominal diameter and flow valves, basically the same breath for full-bore type, Circulation than nominal diameter valve is given.it small called non-reducing type. Non-reducing shapes are uniform and uniform non-reducing non-reducing two kinds. A cone tube shape channel is a kind of non-uniform non-reducing, this kind of valve inlet with the aperture basically the same nominal diameter reduced gradually, and then to the seat place to the minimum.

　　Using non-reducing type port (whether cone tube shape non-uniform non-reducing or even non-reducing), its advantage is the same specifications, can reduce the size of the gate open, and torque, Weakness is the resistance to flow increases, the pressure drop and energy consumption increases, so the shrinkage shoulds not be too big. On cone tube shape non-reducing, seat diameter and nominal diameter ratio, usually take 0.8-95. Nominal diameter less than 250mm non-reducing valve, the valve inside general than nominal diameter lower gear, Nominal diameter is equal to or greater than the non-reducing 300mm its seat diameter valve, general than nominal diameter lower second.