Butterfly valve, also called the flap valve, which is a kind of simple structure of the regulator, also can be used in low pressure pipeline medium valve butterfly valve in the switch control the way work is closed a (disc or disc) is a disc, shaft rotation around the valve to open and close a valve, the valve can be used to control air, water, steam, all kinds of corrosive medium, mud, oil, liquid metal and radioactive medium such as various types of fluid flow. Mainly in the line cut off and throttling effect. Butterfly valve opening and closing is a disc-shaped butterfly plate, the body rotation around its own axis, so as to achieve the aim of opening and closing or adjust. When the valve is closed by the valve plate will wash medium, and fixed media Vibration caused by the valve plate itself, as promised abnormal accelerated destruction of the interlocking member, in particular a solid non-hinged at the self-lubricating bearing deposit destruction. Therefore, the life of the butterfly valve plate rod also non-rod valve life.
Plate or strip produced using the straight pipe joints only industrially several methods, which is different in principle of the method for forming pipe, pipe subsequent processing after molding is essentially the same. Depends on the distribution pipe welds in principle on forming method, according to the distribution pipe welds, it will be divided into two basic forms: straight seam steel pipes and spiral pipes. Corresponding to this, large diameter pipe production into the production of thermal expansion joints straight and spiral seam steel pipe pipe production. Straight seam steel pipes and spiral pipes most widely used method is submerged arc welding (SAW), good quality, high productivity, technology is mature and stable.
The metal blank is rolled by a pair of steel gap (shapes) of the rotating roll, the roll due to the compression of the material cross-section decreases, the pressure processing method of increasing length. Pullout steel is already rolled metal blanks (type, tube, products, etc.) through the die holes pull aside to reduce the length of the section of the increased processing methods are mostly used as a cold. Thus, welded steel pipes played a significant role in the industrial production. Straight seam steel pipe, spiral steel pipe they also play an important role. Forged steel using a reciprocating hammer impact force or pressure to press the blank into a we need to change the shape and size of a press molding method. Extrusion is placed in a sealed steel metal extrusion Jane, pressure is applied at one end of the metal from the extrusion die orifice to obtain a predetermined shape and size has finished with the processing method used for the production of non-ferrous sheet steel.
