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Syringe Pump
This pump is recommended for applications where precise flow control is essential. Because fluids are in contact with plastic only, most common fluids may be pumped. There is no tubing deterioration or creep affecting the flow rate. Also, in the intermittent mode, flow rates are not affected by voltage fluctuations. The pump can hold up to 10 syringes. Different syringe sizes may be used. OperationThere are two modes of operation, continuous and intermittent. In the continuous mode the pump runs continuously, pumping at a rate (using all ten 3 ml syringes) of approximately 120 ml/min. Using a smaller number of syringes results in a proportionally lower pumping rate. For most soil transport studies, the intermittent mode is recommended. In this mode the pump makes one revolution at a time (one pump event). During such a pump event, one or more syringes (up to a maximum of ten syringes) will draw fluid from a supply bottle, and then discharge the fluid onto the column. The motor, which drives the syringes back and forth, then waits for another signal to repeat the filling and discharging of the syringe(s). One such pump event takes about 9 seconds. The volume of fluid discharged per pump event depends on the size of the syringes used as well as on the travel distance of the syringe plunger. For example by changing the travel distance of the plunger, a standard 3 ml syringe can be set to deliver approximately 0.75 ml per event, 1.5 ml per event, 2.25 ml per event, or 3 ml per event. A smaller diameter syringe will deliver smaller volumes. An example of how to calculate pumping rates follows. A good initial leaching rate for unsaturated columns is 10 cm/day. Assume the inside diameter of the soil column is 7.6 cm and its surface area is 45.6 sq cm. At a leaching rate of 10 cm/day, a total of 456 ml of fluid would have to move through the column in one day. This can be accomplished with one syringe set to deliver 1.5 ml per event. At 1.5 ml/event the pump has to make 456/1.5=304 pump events per day. A day has 86400 seconds. A total of 304 pump evens in a day (86400 seconds) requires that the pump be set at an interval of 284 seconds (86400/304=284). Thus setting the pump such that it delivers 1.5 ml every 284 seconds (about 4.7 minutes) results in a flux rate of 10 cm/day through a 7.6 cm ID (3 inch ID) soil column. Once a suitable pumping rate is set, it should remain constant for the duration of the experiment. The syringe pump is designed to do this. Pump intervals varying from 10 seconds to 999 hours can be used. As noted above, in addition to varying the pump intervals, flow rates can further be adjusted by changing the stroke length, using syringes of different diameters, and using different numbers of syringes, resulting in great flexibility in setting the flow rates. In addition one pump may be used to apply water and solute to several columns at the same time. ApplicationsColumn leaching studies. Uniform water and tracer application over larger surfaces (i.e. a total of ten pumps with one external controller have been used to simulate rainfall over a given area). SpecificationsSize: 12"W x 15"L x 4 1/2"H Weight: 15 lbs (6.8 kg) Power: 110VAC or 220VAC The unit comes complete with 10 syringes and two-way valves. ©2006. SOIL MEASUREMENT SYSTEMS |
The ten-channel syringe pump is designed to maintain constant low flow rates over long periods of time. The pump has successfully been used in experiments lasting as short as a few hours to as long as one year.