Bischoff Analysentechnik und -geräte GmbH - HPLC Compact Pump 2250
| Year of introduction
Bischoff Analysentechnik und -geräte GmbH
Chromatography: LC-Pump: Isocratic
Current users of modern HPLC pumps expect to obtain not only minimum pulsation and a solvent independent flow reproducibility, but also an optimum performance over the largest possible ranges of flow and pressure combined with a high resistance against salt solutions in the pump head. Operation should be possible either in stand-alone mode or via a computer or a central processor.
A user-oriented design should allow easy handling and maintenance.
The model 2250 HPLC Compact Pump, manufactured under ISO 9001 satisfies all these requirements and is therefore suitable for use in both simple isocratic and gradient HPLC systems:
The serial dual piston pump with only two check valves gurantees a minimum rest pulsation. The use of an additional pulse damper is generally not necessary even when using pulsationsensitive detectors such as Refractiv Index detector or Electrochemical detector.
Easily interchangeable pump heads cover a wide linear range of flow rates and allow operation with microbore, analytical, preparative and short columns for fast HPLC. Three different pump heads can be used for various application areas.
Electronic pump head identification with automatic control of flow and pressure ranges simplifies the use of the pump for the different applications.
Typical flow ranges are:
Micro pump head
Flow range: 1 - 999 µL/min
Analytical pump head
Flow range: 10 - 4999 µL/min
Preparative pump head
Flow range: 1.0 - 19.99 mL/min
Pump head, stainless steel
The pump head includes the complete liquid delivery unit and is easily accessible for maintenance. Due to the serial arrangement of pistons and the use of only two check valves the model 2250 HPLC Compact Pump combines the advantages of a single piston pump with those of a dual piston pump.
For applications with buffers the pump head can be provided with a piston back wash assembly. Rinsing of high pressure piston seals prevents a possible crystallisation of buffer salts which might penetrate behind the seals through existing micro leakages, thereby causing damage to the seals. Thus, a wet or humid space behind the seal can prevent crystallisation.
Various check valve cartridges are available for different applications and for the analytical, microbore, and preparative flow range.
The model 2250 HPLC Compact Pump can be used for high pressure or low pressure gradients. To run a high pressure gradient you need one additional model 2250 HPLC Compact Pump and the model 1152 Central Processor for gradient control. In low pressure mode there is only the need for the model 1152 Central Processor and the model 1150 Low Pressure Gradientmixer which is available for binary or ternary gradients. Programming of both kinds of gradient modes is the same, there is no need to learn different program structures.
The compact design simplifies maintenance because parts like the pump head are easily accessible. The pump can be upgraded to the latest software version by simply interchanging an EPROM on the main board inside the pump.
Eproms for special applications, such as for slow start-up flow program for column protection are also available.
Flow rate range
Pump head M 0.001 - 0.999 mL/min
Pump head A 0.01 - 4.99 mL/min
Pump head P 0.1 - 19.9 mL/min
Flow rate accuracy at 20 - 80 % FS
< 3 %
< 0.5 %
Pump head M 0 - 60 MPa
Pump head A 0 - 50 MPa
Pump head P 0 - 15 MPa
Pump head volumes (analytical)
- main piston 54 µL
- priming piston 20 µl
Pump displacement volumes
- main piston 45 µL
- priming piston 14 µl
Length of stroke
- main piston 5.6 mm
- priming piston 1.8 mm
Residual pressure pulsation
at 2 mL/min and 20 MPa into a 125 mm column
compensated by setting the proper compressibility < 3 %
a) volume of the pressure transducer 50 µL
b) accuracy 3 %
c) resolution of the display 0.1 MPa
d) recorder output 1 mV/MPa
Pressure shut down
a) maximum switch-off time 0 to FS < 20 ms
b) minimum switch-off time 0.1 to FS 3 cycles
alter initial delay of 2 min
not effective at 0.0 MPa
runs maximum flow of installed head
6 digit LED display with sign and pump head type other than standard
Pump head identification
by 6 push button keys
by contact closures
or active input
a) stop pump
b) reduce flow
by RS 232 or current loop
a) suction phase
b) pump stop
110/220 V ± 10%
+15°C up to +30°C
381 x 255 x 133 mm