GB 6567.4-86 Symbols for Valves and Controllers in Piping Systems
This Chinese national standard is mainly applicable to the graphical symbols for valves and controllers for piping systems used for ships and machinery. It provides basic requirements and dimension tolerances for the form and size of these graphical symbols.
This Chinese national standard defines the graphical symbols for five basic types of valves and four of the most commonly used control elements. In addition, the standard specifies control elements and actuators related to their design and construction.
The graphical symbols of the valves and controllers according to this standard can be applied to graphic representation in establishment of piping system drawings, pipe symbols and process symbols. These symbols can also be used in other document representation forms as long as they are modified in order to fulfill the designated purpose.
The graphical symbols specified in this standard are classified into three categories based on the type of representation. Category one is the direct representation of the valve and persons in their actual size. Category two is the basic representation of the valve and persons in actual size. Category three is the isometric presentation of the valve and persons in actual size.
Each of these graphical symbols is assigned numerical values to assist in their identification. The different parts of the valve are divided according to their structure and numerical values assigned to them. The number 0 corresponds to the valve itself and it is followed by the other components in order to depict their assembly. Besides, numerical values are assigned to the controllers as well to help in their recognition and classification.
The graphical symbols should be drawn as accurately as possible according to the scale specified in the standard. The dimension should be rounded off, but the scale should not be exceeded. Valves should connect smoothly with no sharp edges and the whole design should reflect the simplest form of construction required.
In addition, this standard also states the material classification standards for the valves and persons specified in the standard. Material classifications are made according to various parameters such as temperature, pressure, chemical composition and structure.
It should also be noted that this standard applies mainly to valves and persons and not to other components such as pumps, turbines and hoses. Valves and persons with features that have no equivalent in the symbols given in this standard should be settled by agreement between the supplier and the customer.
In short, GB 6567.4-86 provides comprehensive standards for the graphical representation of valves and persons in piping systems used for the construction of ships and machinery. This standard offers the basis for accurate and uniform representation of graphical symbols and dimensions for these piping systems to ensure the safe and efficient operation of these machines.
