Laboratory vacuum pumps N 8__.3 FT.40.18
Design and Function
Translation of original Operating Instructions, English, KNF 121350-121429 11/18
13
Function Diaphragm Pump
1
Outlet valve
2
Inlet valve
3
Transfer chamber
4
Diaphragm
5
Eccentric
6
Connecting rod
7
Pump drive
Fig. 4: Pump head
Diaphragm pumps transfer, compress (depending on pump ver-
sion) and evacuate gases and vapors.
The elastic diaphragm (
4
) is moved up and down by the eccentric
(
5
) and the connecting rod (
6
). In the downward stroke it aspirates
the gas to be transferred via the inlet valve (
2
). In the upward
stroke, the diaphragm presses the medium out of the pump head
via the outlet valve (
1
). The transfer chamber (
3
) is hermetically
separated from the pump drive (
7
) by the diaphragm.
Description, Operating Conditions
Where gases of high humidity have to be evacuated condensation
may collect in the pump head; as a result, the effectiveness of the
pump decreases.
Thanks to the drying system it is possible during evacuation to
blow the condensed liquid out of the pump heads at high speed,
while maintaining the vacuum in the recipient at a constant level.
After drying the pump heads the pumps achieve a greatly improved
vacuum and evacuate much faster than pumps without a drying
system.
The drying system utilizes the pressure difference between the
transfer chamber (fig. 4/
3
) and the surrounding atmosphere.
The venting valve (fig. 2/
7
or fig. 3/
12
) at suction side pump head is
opened by the control system, permitting air to enter the evacuated
pump head. As a result of the increase in pressure in the pump
head, the inlet valve of the first pump head closes by itself, thereby
sealing off the connection to the source being evacuated.
By contrast, the outlet valve and both valves of the second pump
head now open automatically; the condensation is expelled from
the pump head at high speed.
Pumps can operate with or without the drying system. The drying
system is activated by a switch on the control box. If the drying
system remains switched off the pumps operate in the convention-
al way.
Содержание N 820.3 FT.40.18
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