This paper deals with the system design method of assembly flow line, including determination of the work element time and the balancing problem of the assembly line and buffer storage capacity, etc.

The National Fire Protection Agency (NFPA) Guidelines require a confirming flow test to be conducted whenever a "main line" valve such as the shutoff valves or a backflow assembly have been operated.

The invention has the advantages of good heat radiation, easy flow line production and convenient assembly.