Abstract: A diaphragm valve including a valve housing having at least three ports and at least two valve chambers provided in the valve housing. Each valve chamber has at least one first space communicating with a respective one of the ports and a second space separated from the first space by a threshold. The second space of each valve chamber communicates only with the second space of others of the at least two valve chambers, such that communication between any two of the at least two ports can take place only by passing across two thresholds.

Abstract: A diaphragm valve for controlling a flow of gaseous or liquid fluid and including a valve housing having a valve chamber, into which opens a central channel and on each side thereof a first side channel and a second side channel, respectively, each having an external connection for fluid, valve seats arranged in the housing, an elastic diaphragm adapted to be brought into and away from sealing contact with at least one of the valve seats and controls for actuating the diaphragm. At least one portion of each valve seat is common to the central channel and one of the side channels. Two controls are arranged to press the diaphragm against one such portion each, thereby to shut off the passage of fluid between the central channel and the respective side channel, and to raise one portion each of the diaphragm off the respective portion of the valve seat thereby to open passage of flow between the central channel and the respective side channel.