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These days there are so many different types of syringes and so many different volumes used. Some need a standard syringe from a certain producer; others use only glass, metal or a PTFE syringes. Volumes go from a microlitre to 150 mililitres. Is it possible to satisfy everybody with just a single syringe pump?
With our new VIT-FIT syringe pump we have tried to solve just this problem. Our new syringe fixing system VIT-FIT allows almost any syringe to be used from micro syringes to large volume syringes without the use of an adapter and in addition handling the syringes is made very easy. The syringe is tightly held in both directions Ú infusion and filling.
To move the pusher we have selected a new Swiss made motor which uses new technology to ensure very high torque and ten times longer lifetime. For the transformation of the rotation into a linear movement required for pushing the syringe plunger we have introduced for the first time new Swiss made linear bead bearings. This is an expensive component in our instrument, but it offers decisive advantages to the user in terms of efficiency and the mechanical yield/force of the system. The precise mechanics with a volumetric spiral is protected in the instrument casing and the pusher arm does not reach out from one side (as is usual with existing syringe pumps), but is integrated into the rear of the instrument. The casing and the main body are made of metal with partial PTFE protection. Therefore it is less sensitive to solvents.
The microprocessor electronics allow control of the activity of the pump in an easy but effective way. The movement of the new brushless neodymium magnet motor is constantly under the control of the microprocessor, which corrects immediately any deviation from the pre-set speed. Up to 99 program steps can be memorised by the processor. The pump can be programmed in both directions (for delivery and filling of the syringe). This allows the pump to be used in any way.
Constant flow rate
In this standard application of the pump Ú the flow rate will be kept constant during the pre-selected time period
Profile
exponentially increasing flow rate as used for ex. in Permits varying flow rates to be pre-programmed (including feeding cultures during fermentation, etc.)
Increment
Increasing flow rate in steps over time (to make gradients)
Decrement
Decreasing flow rates steps as above
Pause
Stops the pump for a specified time before going on to the next step
Timer
By programming a required time interval with zero flow rate as the first step the pump can be automatically switched on
Stop
Stops the pump after the program has finished when zero flow rate has been programmed as the last step. If the flow rate of the last step is different from zero then the pump will continue pumping at the specified flow rate until the syringe is empty.
Safe Switching Power Supply
As the mechanical losses are so small we can use a miniature in-plug integrated switching power supply using line voltages from 90 to 240 V AC, 50Ú60 Hz. During field application the pump can be powered by a 12 V accumulator or a 12 V battery.
Automatic switch off
The motor will be switched off when the syringe is empty or has been refilled
Remote control
Several remote control commands are available:
- simple ON/OFF (signal 3 to 12 V DC or higher with resistor)
- progressive speed control over the whole range signal 0 to 10 V DC, (0 to 20 or 4 to 20 mA option)
- RS 485 interface (option) for communication with a PC or similar device
Speed selection / syringe calibration
To be able to fit the many types of syringes used, the speed selection is made using speed numbers corresponding to the velocity of the rotation of the motor. The selected syringe has to be calibrated. This means that the speed number (from 000 to 999) has to be put into relation with the delivered volume as a function of time (flow rate). The delivered volumes and flow rates as well as settings are then easily calculated.
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