Description
115051
11
3.1.2
Diaphragm pump
► Design:
The diaphragm pump consists of a pump body and a drive motor.
The pump body consists of a drive shaft and four pump heads. Each pump head contains
the diaphragm and the work valves. The two pump heads are arranged opposite each other.
In a three-stage (T) diaphragm pump, the two pump heads are connected in parallel, two fur-
ther pumps in series.
The pump heads are driven via an eccentric shaft with a connecting rod.
► Function:
Motor, eccentric shaft and connecting rod set the diaphragms in stroke movement. This
changes the size of the space between the diaphragms and pump head (pump chamber).
Increasing the size of the pump chamber opens the inlet valve while the outlet valve is
closed (intake process). Decreasing the size of the pump chamber ejects the gas through
the outlet valve.
The valves are actuated by the gas being pumped. A large proportion of fluid in the dia-
phragm pump minimizes the pumping efficiency.
► Materials of the medium-affecting pump parts:
Component
Materials
Seal
EPDM
Screw fitting / Connecting elements
PP, PVDF
Valve
PEEK
Diaphragm
Ela PTFE layer
Vacuum hose
PTFE
Connection head / pump head
PTFE with carbon-fibre reinforcing
*)
*)
electrically conductive (with manufacturer's certificate of electrical conductivity)
Material resistance to aggressive media see: Publisher Hoppenstedt Publishing (18. September 2007)
► Gas ballast:
When condensable vapours are pumped,
they may be compressed above the
saturated vapour pressure and condense.
Opening the gas ballast valve (17) in the
suction line of the last pump stage allows
air to flow into the pump chamber.
This prevents condensation and flushes
the pump clear.
Operation leads to increasing the ultimate pres-
sure and the operating temperature.
Fig. 2 Diaphragm pump MPC 601 T
