A valve comprising housing body, partition plate, and collecting device. The housing body defines a housing cavity. The partition plate is provided in the housing cavity. A leakage passage extends along the partition plate through the housing body. The collecting device comprises a lower piece, an upper piece, and a connector connecting them. The upper piece and the lower piece cover a leakage passage upper port and a leakage passage lower port, respectively. The lower piece comprises a collecting cavity communicating with the leakage passage lower port. The lower piece and lower part of the housing body are provided with lower fitting assembly. The upper piece and upper part of the housing body are provided with an upper fitting assembly. The lower piece and the upper piece are fitted on the housing body in place by means of the lower fitting assembly, the upper fitting assembly and the connector.