Page 1: Table Of Contents
8 Replacement parts 9 Appendix 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.
Page 2: Scope Of Delivery
Table 2: Enclosed items Optional accessories: Water jet pump B-764, complete 31358 Water jet pump B-767, complete with 31357 Figure 1: General view of the B-720 cooling valve Cooling water valve, complete 31356 Two-way solenoid valves, 24 VDC: Type for 1-liter Rotavapor...
Page 3: Safety
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.
Page 4 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.
Page 5: Function
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.
Page 6 3 Function BÜCHI Vacuum Controller B-720 3.2 Manual hysteresis The tolerance range of the operating point can be selected automatically as well as manually. Example: 407 mbar Nominal pressure 400 mbar, manual hysteresis 7 mbar. 7 mbar 400 mbar The pump evacuates to the desired pressure of 400 mbar, the two-way valve closes or the vacuum pump switches off.
Page 7: 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 Valve connection 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...
Page 8 Water faucet Woulff bottle trap Needle valve Figure 8: The B-720 with a two-way valve and a cooling water valve Cooling water valve Vacuum pump Two-way valve 4.3 Installation with a B-764 water jet pump •...
Page 9: Büchi Vacuum Controller B
• Turn the water faucet on and use the needle valve adjust the flow through the condenser. Water faucet Figure 11: The B-720 with a vacuum pump, a B-745 Switch-box and a Woulff bottle trap cooling water valve Needle valve...
Page 10: Operation
Stop the distillation process «STOP». STOP BÜCHI B†CHI Vacuum Controller B-720 Figure 12: The membrane keypad on the B-720 5.2 Normal operation 1. Set the power switch to ON. 2. Use «P» with «UP» or «DOWN» to select and set the desired value of your choice.
Page 11 BÜCHI Vacuum Controller B-720 5 Operation 5.3 Detailed description of the various functions The numbers used in the following examples were chosen at random and serve only to explain the functions. Action Display Function Switch on «On» switch • Displays actual system pressure the unit (current system pressure) •...
Page 12 5 Operation BÜCHI Vacuum Controller B-720 5.4 Hold state After distillation is started, you can use the arrow keys to intervene in the automatic control sequence at any time. Pressing «UP» causes an immediate increase of the system pressure (the system is aerated), pressing «DOWN» decreases the system pressure.
Page 13 BÜCHI Vacuum Controller B-720 5 Operation 5.5 Working example The values in the following example apply for the distillation of ethanol. For the values of other solvents, please consult the table at the end of this section. Check the following items before each distillation: •...
Page 14 5 Operation BÜCHI Vacuum Controller B-720 5.6 Solvent Solvent Formula Molary weight Energie of Boiling point in °C Tightness Vacuum in mbar in g/mol evaporation in J/g at 1013 mbar in g/cm for boiling at 40 ºC Acetic acid 60.0 1.049...
Page 15: Maintenance
The calibration range is ± 20 mbar. 6.3 Customer service Only authorized customer service technicians are permitted to intervene service the Vacuum Controller B-720. They have undergone thorough professional training and are familiar with the hazards that ensue from ignoring safety precautions. The addresses of Büchi Customer Service Centers are listed on the...
Page 16 6.5 Block diagram of the B-720 Membrane keypad CPU print Power print Euro power plug Ceramic pressure sensor Ventilation valve Figure 13: Block diagram of the B-720 6.6 Troubleshooting Malfunction Possible cause Remedy Valve opens and closes at high rate System has a leak...
Page 17: Taking Out Of Operation
BÜCHI Vacuum Controller B-720 7 Taking out of operation 7 Taking out of operation 7.1 Storage / Transportation The unit should be stored in a dry place in its original packaging. 7.2 Disposal Material codes are marked on each large component. Please observe your regional and local laws concerning the disposal of waste materials.
Page 18: Replacement Parts
8 Replacement parts BÜCHI Vacuum Controller B-720 8 Replacement parts The Vacuum Controller’s operational safety and serviceability are guaranteed only by original Büchi parts. The use of other makes of replacement parts and accessories is permitted only with the express consent of Büchi.
Page 19 BÜCHI Vacuum Controller B-720 8 Replacement parts B-767 Water jet pump 31357 Figure 16: B-767 Water jet pump Cooling water valve 31356 Figure 17: Cooling water valve...
Page 20 8 Replacement parts BÜCHI Vacuum Controller B-720 Two-way valve 24 VDC 31353 Ø 8 mm for 1-liter Rotavapor Figure 18: Two-way valve for 1-liter Rotavapor Two-way valve 24 VDC 31354 Ø 12 mm for 20-liter Rotavapor Figure 19: Two-way valve for 20-liter Rotavapor...
Page 21: Büchi Switch-Box B
BÜCHI Vacuum Controller B-720 8 Replacement parts Büchi Switch-box B-745 CH 36410 Connecting cable, non-return valve incl. B-745 B†CHI Switch-box Figure 21: Switch-box B-745 CH Büchi Switch-box B-745 D 36411 Connecting cable, non-return valve incl. B-745 B†CHI Switch-box Figure 22: Switch-box B-745 D Büchi Switch-box B-745 International...
Page 22: Woulff Bottle Trap, Plastic + Glas
8 Replacement parts BÜCHI Vacuum Controller B-720 Vacuum hose 16 / 6 mm 17622 Nyflex hose 14 x 8 (Alternative to the vacuum hose 17622) 04113 Figure 25: Vacuum hose Woulff bottle trap, PLASTIC+GLAS, complete 25519 Figure 26: Woulff bottle trap, PLASTIC + GLAS Bottle clamp Ø...
Page 23: Appendix
BÜCHI Vacuum Controller B-720 9 Appendix 9 Appendix 9.1 Technical data Voltage 230 V / 50 … 60 Hz 120 V / 50… 60 Hz Power consumption 14 W Solenoid valve input 28 VDC Control range pressure 1 mbar / Torr – atmospheric pressure Max.
Page 24 9 Appendix BÜCHI Vacuum Controller B-720 9.3 Declaration of EC conformance BÜCHI Labortechnik AG Postfach, CH-9230 Flawil Switzerland declare under our sole responsibility that the product: BÜCHI Vacuum Controller B-720 to which this declaration relates is in conformity with the following standards:...