BÜCHI Vacuum Controller B-720
Contents
Contents
1 Scope of delivery 2
2 Safety 3
3 Function 5
4 Putting into operation 7
5 Operation 10
6 Maintenance 15
7 Taking out of operation 17
8 Replacement parts 18
9 Appendix 23
Read these operating instructions carefully before you use the
Büchi Vacuum Controller B-720. Keep these instructions in a
safe place preferably close to the Vacuum Controller for quick
reference whenever required.
Chapter 2, Safety contains important notes concerning safety.
It is imperative to read these notes in order to operate the Vacuum
Controller safely.
Contents are subject to change without prior notice. No part of
these operating instructions may be reproduced in any form or
be processed, duplicated or distributed by electronic or optical
means without the written permission of Büchi Labortechnik AG.
All rights reserved. Copyright © Büchi Labortechnik AG, 1995
en, Version D (24 pages) Order No.
B-720 Instructions 96601
1
1 Scope of delivery
BÜCHI Vacuum Controller B-720
1 Scope of delivery
Description
Models: Order No.
Büchi Vacuum Controller B-720 230 V 34860
Büchi Vacuum Controller B-720 120 V 34960
Table 1: Scope of delivery
Enclosed items:
1 D12-16 cross clamp, complete 27347
1 GL 14 hose connector, complete 32885
1 Instructions in the following languages:
German 96600
English 96601
Figure 1: General view of the B-720
Figure 2: complete D12– 16 cross
clamp
Figure 3: complete GL14 hose
connector
French 96602
Italian 96603
Spanish 96604
1 Packaging, complete
Table 2: Enclosed items
Optional accessories:
Water jet pump B-764, complete 31358
Water jet pump B-767, complete with 31357
cooling valve
Cooling water valve, complete 31356
Two-way solenoid valves, 24 VDC:
Type for 1-liter Rotavapor 31353
Type for 20-liter Rotavapor 31354
Type for 50-liter Rotavapor 31355
Büchi Switch-box B-745:
Type CH 36410
Type D 36411
Type International 36412
Adapter cable 31225
U.S. adapter cable 33369
Woulff bottle trap, PLASTIC+GLAS 25519
Bottle clamp 11152
Rod 32008
Table 3: Optional accessories
2
BÜCHI Vacuum Controller B-720
2 Safety
2 Safety
The Vacuum Controller is built in accordance with the art of
engineering and the recognized rules of safety.
Nevertheless, it can still be a source of risks and hazards:
• if used by persons with insufficient training.
• if used for purposes other than that for which it is intended.
2.1 Symbols
Stopp
Information about hazards which can lead to extensive material
damage or cause serious or potentially fatal injury.
Warning
Information about hazards which can be harmful to your health
or lead to material damage.
Please note
Information about technical requirements. Non-observance can
lead to malfunctions, inefficiency and possibly even lost production.
2.2 Requirements to be met by the customer
The Vacuum Controller may only be operated by persons
capable of comprehending the hazards that can arise during
its use.
2.3 Proper use
The Vacuum Controller is designed and built for laboratory
operation. It is to monitor and control vacuum levels over a
working range from 0 mbar to atmospheric pressure.
Typical applications include:
• Distillation apparatus, especially rotary evaporators
• Vacuum filtration
• Vacuum impregnation
For the Vacuum Controller to be used properly, it must also be
cleaned and maintained with routine care.
3
BÜCHI Vacuum Controller B-7202 Safety
2.4 Improper use
Any use other than those already listed and any application that
does not conform with the technical data is deemed to be a
case of mis-use. The customer shall bare sole responsibility for
any damage caused by such mis-use.
The following applications in particular are prohibited:
• Use as a calibrating unit for other equipment
• Use as a barometer
• Use in hazardous duty areas or areas designated as Explo-
sion Proof
• Operation in overpressure
·
2.5 Safety measures
It is imperative to wear personal safety items such as goggles,
protective clothing and gloves.
These operating instructions are to be considered part of the
B-720 Vacuum Controller. They must always be kept near the
unit so operating personnel can consult them at any time.
The customer is responsible for instructing subordinate
personnel. These operating instructions can be ordered in other
languages for this purpose.
The customer shall notify the manufacturer immediately of any
safety incidents involving the B-720 Vacuum Controller.
2.6 Safety elements
A built-in ventilation valve vents the system automatically upon
reaching a level of overpressure in excess of 1400 mbar.
4
BÜCHI Vacuum Controller B-720
3 Function
3 Function
The B-720 keeps a selected level of vacuum constant. It
automatically compensates any loss of vacuum in the evacuated
system by re-adjusting the vacuum to the set pressure level. It
does so by actuating a two-way valve in the vacuum line or by
directly switching the vacuum source on and off.
Solvent can be condensed with hight efficiency if the optimum
vacuum level is selected for the specific solvent. This results in
an immense reduction of solvent through the vacuum pump or
in a laboratory’s waste water.
You can also use the B-720 to control the flow of cooling water
during distillation. This is done by actuating a cooling water valve.
Water savings of up to 95% are possible this way.
All B-720 models are delivered as standard with an aeration
valve, also used for purging with inert gas, a cross clamp for
mounting on a stand, and a GL14 hose connector for connecting
the vacuum hose.
3.1 Functions of the various keys
«P» You can set the desired value of your choice with
the arrow keys. If no key is pressed within 3 seconds,
the display will switch to its initial state and the
setdesired value will be saved automatically.
«욼P» You can set the desired hysteresis in mbar or Torr
with the arrow keys. If no key is pressed within 3
seconds, the display will switch to its initial state
and the setdesired value will be saved automatically.
«UP» Press this key to increase the desired value.
«DOWN» Reduces the pressure or hysteresis during distil-
lation.
«mbar/Torr»Switches the LED display from mbar/hPa to Torr/
mm Hg.
«START» Starts the evacuation process.
«STOP» Stops the vacuum process. The system is ventilated,
but the cooling water valve does not close until 5
minutes later. Press twice for the cooling water to
be switched off immediately.
Figure 4: The keypad on the B-720
5
3 Function
BÜCHI Vacuum Controller B-720
P
407 mbar
400 mbar
0
0
Figure 5: Manual hysteresis
P
412 mbar
400 mbar
0
0
Figure 6: Automatic hysteresis
1
1
3.2 Manual hysteresis
The tolerance range of the operating point can be selected
automatically as well as manually.
2
7 mbar
3
Example:
Nominal pressure 400 mbar, manual hysteresis 7 mbar.
The pump evacuates to the desired pressure of 400 mbar,
the two-way valve closes or the vacuum pump switches
off.
t
The pressure rises by 7 mbar.
The pump evacuates again to the desired value.
3.3 Automatic hysteresis
The automatic hysteresis function works by continuous (linear)
degression.
2
12 mbar
• 30 mbar for a desired value of 1000 mbar
• 1 mbar for a desired value of 2 mbar
Example:
Nominal pressure 400 mbar, automatic hysteresis 12 mbar.
The pump evacuates to the desired value of 400 mbar,
the two-way valve in the main vacuum line closes or the
vacuum pump switches off.
t
The hysteresis tolerance range for this desired value
amounts to 12 mbar.
6
BÜCHI Vacuum Controller B-720
4 Putting into operation
4 Putting into operation
Check that the voltage of the power supply corresponds to the
value marked on the B-720 rating plate.
4.1 Connections on the side
V Valve connection
V
CW
CW Cooling water valve connection
Power switch
Fuse (at the left-hand side of the housing)
Figure 7: The right-hand side of the B-720 housing
7
4 Putting into operation
BÜCHI Vacuum Controller B-720
Figure 8: The B-720 with a two-way valve and a cooling water valve
4.2 Installation with a two-way valve and a
cooling water valve
• Install the two-way valve between the vacuum pump
and the woulff bottle .
• Connect the two-way valve to the socket V.
• Screw the cooling water valve onto the water faucet
(remember the seal and screen).
• Insert the cooling water valve plug in the socket CW.
• Connect the cooling water hoses.
• Connect the B-720 to the power supply.
• Switch on the B-720.
• Turn the water faucet on and use the needle valve to
adjust the flow through the condenser.
Water faucet
Woulff bottle trap
Needle valve
Cooling water valve
Vacuum pump
Two-way valve
Figure 9: The B-720 with a B-764 water jet pump
4.3 Installation with a B-764 water jet pump
• Attach the B-764 water jet pump to the water faucet.
• Insert the valve plug in the socket V.
• Fully open the water faucet .
• Connect the cooling water hoses.
• Connect the B-720 to the power supply.
• Switch on the B-720.
• Turn on the water faucet .
Water faucet
Woulff bottle trap
B-764 water jet pump
Water faucet
8
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