Diaphragm liquid pump NF 30, NFB 30
Assembly and function
KNF Flodos AG BA_NF30_EN_05_069206.docx
Translated from the Original Operating and Installation Instructions
10
5. Assembly and function
Assembly
1
Outlet
2
Inlet
3
Head plate
4
Connecting plate
5
Intermediate plate
6
Motor
Fig. 1 Diaphragm liquid pump
1
Exhaust valve
2
Inlet valve
3
Working chamber
4
Diaphragm
5
Eccentric
6
Connecting rod
7
Pump drive
Fig. 2: Operating principle
Diaphragm liquid pumps are based on reciprocating displacement
pump technology. An elastic diaphragm (
4
) is moved up and down
by the eccentric (
5
) and the connecting rod (
6
). During the down
stroke, the diaphragm sucks in the medium through the inlet valve
(
2
). During the up stroke, it forces medium out of the pump head
through the exhaust valve (
1
). The diaphragm hermetically seals
off the working chamber (
3
) from the pump drive (
7
).
NF 30 version (specified flow rate)
This pump type represents this product in its simplest form and
delivers media at the specified flow rate.
NF 30 .27 version (specified flow rate with overpressure
limiting)
If the diaphragm liquid pump is operating against a closed system,
the delivery pressure quickly exceeds the maximum permissible
values. To prevent this happening, an overpressure relief is
integrated in the top part of the pump head. If the pressure
exceeds the variable limit range (min. 0.5 to max. 1.0 bar
g
), the
valve opens and the liquid circulates from the pressure side to the
suction side via an internal bypass system. This prevents any
further rise in pressure.
