Design And Function - VWR VP 820 Manual Del Usuario

Power consumption pump [W]
Electrical Data
Maximum permitted mains voltage fluctuations
Fuse pump** (2x) T [A]
Protection class motor
Tab. 3
5.

Design and Function

Design (symbolic)
1 Connection piece
2 Pneumatic connection
3 Pump head
4 Outlet (pressure side)
5 Inlet (suction side)
Fig. 2
Diaphragm pumps transfer, compress (depending on pump version) 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
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. 3/3) and the
surrounding atmosphere.
The venting valve (fig. 2/7) 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 witched off the pumps operate in the conventional way.
120
+/- 10 %
1.6
IP44
6 Power switch pump
7 Venting valve
8 Power switch drying
system
9 Control box
* Liters in standard state (1,013 mbar)
** For spare part-No. see chapter 10
Function Diaphragm Pump
1 Outlet valve
2 Inlet valve
3 Transfer chamber
4 Diaphragm
5 Eccentric
Fig. 3: Pump head
English
6 Connecting
rod
7 Pump drive
7