Valves commonly used assembly method can be three kinds, namely, complete interchangeable method, repair method and selection method.

(1) complete interchangeable method

Valve assembly using the complete interchangeable method, each part of the valve does not have to go through any trimming and selection can be assembled, assembled products that can meet the specified technical requirements. At this time, the valve parts should be completely in accordance with the design requirements of processing to meet the requirements of dimensional accuracy and form tolerance.

Completely interchangeable method has the advantage of: assembly work is simple, economic, workers do not need a high level of technology, assembly process of high productivity, easy to organise assembly line and organisation of specialised production, but relatively speaking, the use of complete interchangeable assembly, for the parts of the higher processing accuracy requirements. Suitable for globe valves, check valves and other relatively simple structure of the valve class and small diameter valves.

(2) Matching method

Valve assembly using the matching method, parts can be processed according to the economic accuracy, assembly and then a regulation, compensation function of the size of the selection, in order to achieve the required assembly accuracy. The principle of the selection and fitting method is the same as the repair and fitting method, only in the method of changing the size of the compensation ring is different. The former is the method of selecting fittings to change the compensation ring size, the latter is the method of trimming fittings to change the compensation ring size. For example, the top core and adjustment gasket of double gate wedge gate valve and the adjustment gasket between the two bodies of folio ball valve, etc., is to choose special parts as compensation parts in the size chain related to assembly accuracy, and to adjust the thickness of the gasket size to achieve the required assembly accuracy. In order to ensure that in different cases can be fixed compensation parts for selection, it is necessary to pre-produce a set of different thickness dimensions of the gaskets, bushings compensation parts, for assembly selection.

(3)Repair method

Valve assembly using the repair method, parts can be processed according to the economic accuracy, assembly and then a regulation, compensation function of the size of the repair, in order to achieve the specified assembly purpose. Such as the gate valve gate and valve body, due to the realization of the interchangeable requirements of the processing cost is too high, the majority of manufacturers are using the repair method process. That is, in the final grinding of the gate sealing surface control of the opening size and the valve body sealing surface of the opening size of the matching method for the ‘board’, in order to achieve the final sealing requirements. Although this method increases the ‘match plate’ process, but greatly simplifies the dimensional accuracy requirements of the previous processing procedures, ‘match plate’ process of skilled operation, in general, will not affect the production efficiency.