MEMDOS ZGMR

Catalogue

Drawing Dimensions

Instruction Manual

General
Double diaphragm metering pumps of the MEMDOS GMR series can be supplied as single or duplex metering pumps. The pumps are used to meter large quantities at relatively low back pressures. They are frequently used in waste-water treatment to meter pH-regulating chemicals or flocculents.

The metering pumps are available in three sizes as single metering pumps for 2000 to 4000 l/h. Different metering heads can be connected to the duplex metering pumps. The metering heads are then operating in a reciprocating mode and the quantity
metered is set for both heads at the same time.

Designs
Standard designs are: Single metering pump with lefthand
metering head arangement. Type designation GMR Symbol Duplex metering pumps with two metering heads. Type designation ZGMR Symbol

Metering head
The characteristic feature is the duplex diaphragm (7+8). The eccentric (5) guides the diaphragm (7) almost following the sine wave over the constant stroke. Since the large supporting disks always carry the whole surface of the diaphragm (7) in the maximum eccentric positions, a piston-like displacement effect is achieved. This results in a very high metering accuracy for diaphragm metering pumps independent of the back pressure.

The front supporting disk for the suction stroke must not get into touch with the medium because of chemical resistance and the possible abrasivity. Therefore, a second diaphragm (8) is provided, which has a merely separating function and is therefore neutral in respect to forces. The medium side of the EPDM separating diaphragm (8) is coated with PTFE.

A precisely dimensioned glycerin filling (6) acts as hydraulic push rod and thus the distance between the
two diaphragms remains constant. Also the rear diaphragm chamber is partly filled with glycerin for
lubrication purposes. The suction (12) and discharge valves (13) are single-ball valves. The suction (11) and discharge connections (10) are available in plastic or stainless steel design.