Unit 1, Anglian Business Park, Orchard Road, Royston, Hertfordshire, SG8 5TW, UK T: +44 (0)1763 242491 F: +44 (0)1763 246125 E: sales@dolomite-microfluidics.com W: www.dolomite-microfluidics.com Dolomite Microfluidics North America Office Blacktrace Inc, 29 Albion Place Charlestown, MA 02129, USA C: 617 803 6655 T: 617 848 1121 F: 617 500 0136 E: salesus@dolomite-microfluidics.com Mitos Fluika Pressure and Vacuum Pumps Datasheet product datasheet page Description 2 Benefits 3 Theory and Performance 3 Specification 6 Performance 12 Dimensions 13 The Dolomite Centre Limited Page 1 of 13
Part name Part number Mitos Fluika Low Pressure Pump 3200418 Mitos Fluika Low Vacuum Generator Pump 3200419 Description These compact pressure and vacuum generators are designed to provide pressurized air or vacuum with fast and accurate pressure control. They are easy to set up and use, requiring no gas supplies or external vacuum pumps. This makes them perfect for OEM integration. Moreover, power and control is supplied through a USB port only. There are 2 versions: Mitos Fluika Low Pressure Pump for pressures above atmospheric pressure Mitos Fluika Low Vacuum Generator Pump for pressures below atmospheric pressure Both generators have a single pressure channel/outlet, which is accessed via a 4mm tube push-fit pneumatic connector on the front panel of the device. Example of system configuration Warning! If you are using the same setup with the Vacuum Generator, make sure that the substrate reservoir is sufficiently large enough for the experiment. It is very important to protect the device from any liquid ingress. MAR-000135_v.A.20 Page 2 of 13
Benefits Miniature (~10 x 6 x 3 cm) Perfect for integration Easy to interface with pneumatic quick-fit connectors Fully USB controlled and powered. No extra power supplies or cables No extra pumps or pressure sources needed Easy to control and program (.NET, LabView, MATLAB) Switching between two pressure or vacuum levels is possible when used with the Mitos Fluika Control Valve Low noise Low cost Theory and Performance Performance of the pressure and vacuum pumps is described by: Pressure range Accuracy Stability/Fluctuations Flow rate Response time In order to facilitate general understanding and more detailed calculations of exact performance, a brief overview is given here. It is useful to note the analogy between electrical circuits and fluidics, where fluidic resistance and compliance take the place of electrical resistance and capacitance. The pumps, valves and reservoir can be approximately represented by an equivalent scheme given on figure 2. Pressure and/or vacuum pump Figure 2: Equivalent scheme of Mitos Fluika pressure and/or vacuum pumps together with an example of external circuitry. For the following discussion we can define notations - pressure, - flow rate ( ), - fluidic resistance ( ), fluidic compliance ( ). We can assume that pressure changes during operation are small compared to overall pressure (. In this case, using ideal gas law, we can derive differential form, which gives. MAR-000135_v.A.20 Page 3 of 13
Pressure regulation is achieved by the inflation and deflation of an internal reservoir (with compliance ), from two internal pressure sources:, which is the source of high pressure; and, which is the source of low pressure. Both pressure sources can be considered ideal, meaning pressure does not depend on flow rate. These pressure sources, however are coupled through loading resistances of and respectively. Inflating and deflating is controlled by control logic, which is feedbacked through a pressure sensor. The system can also have a small internal leak. This RC type of loading is in general described by differential equation: where is either or for decreasing and increasing pressures respectively. is also correspondingly or. This equation has the solution: where is a time constant, which, depending on the loading polarity, will later be denoted either or. Finally, is the time delay needed for changing pressure from to. Thus transient pressure response is described by the exponential approach towards pressure source values. This is schematically illustrated on figure 3. Since feedback and valve actuation is associated with small delay and uncertainty, it can result in an initial overshoot, which thereafter relaxes during, which is needed so that the pressure will be within the tolerance range. It must be noted that and define an always larger pressure range than supported by the device ( ). The supported range has a safety margin to ensure stable operation. Figure 3: The temporal response of the output pressure p_out to change in the pressure settings from level p_0 to p_1. The set pressure is depicted with a red line, while a blue line represents the actual pressure at the device output. Green is the tolerance corridor of the output pressure value. MAR-000135_v.A.20 Page 4 of 13
External circuitry The actual time response is also highly dependent on external circuitry (eg. figure 2). Large external volume ( ) would slow the response time, which would become: On the other hand external volumes stabilize the stationary holding states of output pressure. External leak can also slower the time response, but also limit maximum achievable pressure as pressure generator has limited flow capability. Maximum flow at each pressure ( ) would be approximately: Stability and accuracy Accuracy of the pumps is characterized by two parameters: accuracy of the internal pressure sensor (which describes the device s own pressure sensing capabilities) and overall accuracy of the output pressure, corresponding to the difference of the true output pressure value after the stabilization time vs the set pressure level dictated to the device. Stability reflects the magnitude of the fluctuation, which emerges due to the impulse charging and discharging of the internal reservoir. Device self-protection The devices will switch off pumping automatically if they have not received a command from the computer for 5s. Normally the computer program would continuously request the pressure value to check the system status. If the computer goes to standby or the operation program is closed (which usually would mean that the experiment is finished) the pump will switch off. This is to protect the pump from unintentional lengthening of running time and would extend its life expectancy. MAR-000135_v.A.20 Page 5 of 13
Specification Here, specific information about pressure and vacuum pumps has been provided. Model and parameters are mostly given for small (~zero) external volumes. Large external volumes can cause deviations from the model due to non-linearity. Mitos Fluika Low Pressure Pump: Description Symbol Min Typical Max Unit Pressure range of the device 0 500 Inflating pressure a 750 900 1200 Deflating pressure 0 Volume of internal reservoir 13.2 Internal compliance 1.3 x 10 - Inflating time constant 1.3 1.8 Deflating time constant 1.1 1.2 Effective inflating resistance 1.0 x 10 10 Effective deflating resistance 8.3 x 10 9 Leak resistance 1.5 x 10 13 10 3.7 x 10 13 Pressure overshoot b 50 Pressure reach time (on inflation) c Pressure reach time (on deflation) c Pressure stabilization time (inflation) Pressure stabilization time (deflation) 1.5 3 3 6 2 5 6 10 Pressure sensor accuracy 1.5 2.5 Combined pressure output accuracy / stability Min. sensor reading (At 0 mbar) d 3 5 2800 Internal unit Max. sensor reading (At 500mbar) d 25000 Internal unit MAR-000135_v.A.20 Page 6 of 13
a Pumping pressure is given in case of no or minimal external volume. Large external volume would reduce effective due to non-linear effects. b Combines overshoots both on inflation and deflation. Magnitude of overshot is dependent on the pressure range. c Depends on particular pressure change. Approach is slower closer to target pressure. d Varies device to device and depends on sensor calibration. Performed for each device during manufacturing. Below some test results and examples are given: Figure 4: Response to pressure increase from 0 to 500mbar (left) and decrease from 500 to 0mbar (right). Both show response without external load (blue line) and with external load of 50mL (green line). Red line is showing fit of the response to exponential functions, as described above. Figure 5: Step response. Pressure is increased and decreased in discrete steps of 100mbar. Response (left figure) is shown without load (blue line) and with load of 50mL (green line). Red line represents the set pressure level. Right graph represents the total stabilization time required for each pressure setting steps. Device to device variations given as error bars with 2x standard deviation (95% confidence interval) are obtained through statistics of large number of devices. MAR-000135_v.A.20 Page 7 of 13
Figure 6: Pulse response similar to figure 5. Pulses are between pressure and 0 level, while the height of the pulses is increased in steps of 100mbar. Figure 7: Output pressure calibration and stability versus set pressure (left). Deviation of internal pressure sensor reading from external reference manometer (right). Figure is showing eight randomly chosen exemplary devices, where the green region shows precision range defined in specification. Pressures and sensors were tested with reference manometer (Precision ±0.3mbar). MAR-000135_v.A.20 Page 8 of 13
Mitos Fluika Low Vacuum Generator Pump: Description Symbol Min Typical Max Unit Pressure range of the device -350 0 Inflating pressure a -430-400 -370 Deflating pressure 0 Volume of internal reservoir 13.2 Internal compliance 1.3 x 10 - Inflating time constant 0.6 0.7 0.8 Deflating time constant 1.1 1.2 1.3 Effective inflating resistance 5.4 x 10 9 Effective deflating resistance 9.2 x 10 9 Leak resistance 0.5 x 10 13 10 6.5 x 10 13 Pressure overshoot b 50 Pressure reach time (on inflation) c Pressure reach time (on deflation) c Pressure stabilization time (inflation) Pressure stabilization time (deflation) 1.5 3 4 8 2 5 6 10 Pressure sensor accuracy 1.5 2.5 Combined pressure output accuracy / stability Min. sensor reading (At -350 mbar) d Max. sensor reading (At 0 mbar) d 3 5 18300 Internal unit 2800 Internal unit a Pumping pressure is given in case of no or minimal external volume. Large external volume would increase effective due to non-linear effects. b Combines overshoots both on inflation and deflation. Magnitude of overshot is dependent on the pressure range. c Depends on particular pressure change. Approach is slower closer to target pressure. d Varies device to device and depends on sensor calibration. Performed for each device during manufacturing. MAR-000135_v.A.20 Page 9 of 13
Some test results and examples are given below: Figure 8: Response to applying vacuum from 0 to -350mbar (left) and deflation of vacuum from -350 to 0mbar (right). Both show response without external load (blue line) and with external load of 50mL (green line). Red line is showing fit of the response to exponential functions, as described above. Figure 9: Step response. Vacuum is increased and decreased in discrete steps of 50mbar. Response (left figure) is shown without load (blue line) and with load of 50mL (green line). Red line represents the set pressure level. Right graph represents the total stabilization time required for each pressure setting steps. Device to device variations given as error bars with 2x standard deviation (95% confidence interval) are obtained through statistics of large number of devices. MAR-000135_v.A.20 Page 10 of 13
Figure 10: Pulse response similar to figure 9. Pulses are between pressure and 0 level, while the height of the pulses is increased in steps of 50mbar. Figure 11: Output pressure calibration and stability versus set pressure (left). Deviation of internal pressure sensor reading from external reference manometer (right). Figure is showing eight randomly chosen exemplary devices, where the green region shows precision range defined in specification. Pressures and sensors were tested with reference manometer (Precision ±0.3mbar). MAR-000135_v.A.20 Page 11 of 13
Dimensions Length: Width: Height: 100mm 60mm 30mm MAR-000135_v.A.20 Page 12 of 13
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