View Full Version : Syringe Pumps

Kirk Keyes
12-16-2008, 12:20 AM
Anyone here using syringe pumps - and are interested in talking about how they use them? I'm interested in why you choice to use one, how you've found it to work, and what you benefits or disadvantages you've found. Also, what volume sizes and flow rates do you use.

I have a peristaltic pump and I'm curious about syringe pumps.


Mark Fisher
12-16-2008, 08:48 AM
I've used both peristaltic and syringe pumps for medical work. Syringe pumps are much more accurate. They are capable of extremely low flows. They require more complicated drive systems. Peristaltic pumps are cheap, can provide high flows and are accurate enough for some applications. Peristaltics are often used when the fluid simply needs to be moved from one place to another.

Nicholas Lindan
12-16-2008, 05:23 PM
I have a peristaltic pump and I'm curious about syringe pumps.

Like a Hamilton - http://www.hamiltoncompany.com/diluters/dil_works.asp?

A dispenser/diluter works in discrete doses, it isn't a continuous flow system like a peri pump.

It works like a syringe, except that the the material to be dispensed is drawn up into a probe, not the body of the syringe, seperated from the diluent by an air bubble. The probe is a teflon coated fine steel tube attached to the d/d by a length of semi-rigid tubing.

The tube is then moved to the dispense position and the sample and air bubble are ejected from the tube. If the material is to be diluted then a volume of diluent is dispensed following the air bubble.

A valve at the head of the syringe then rotates and the syringe draws diluent from the diluent bottle, the valve rotates again and the diluent is dispensed into a waste container to wash away any remains of the material from the inside of the probe. Diluent for the next dilution is left in the syringe.

If used in an automated system the probe is attached to the end of a robotic arm.

A d/d on the salvage market can go for pennies on the dollar - depends on who sees it and bids. New, figure $1-4K for the d/d and a couple more $k for the robotic arm.

Why use one: precision, low carry-over.
What they are used for: clinical chemistry.
Flow rates: a few microliters to a milliliter per cycle. Figure 5 seconds or so per cycle.

I can't see one of these in a continuous flow process as they have to pause and refill at the end of every stroke. They are strictly batch machines.

Photo Engineer
12-16-2008, 06:00 PM
Emulsion making is a batch process that revolves around precise delivery of a measured quantity of solution, but it involves no dilution under normal circumstances. IDK if the pumps referred to above would work unless they were used for direct delivery.


Kirk Keyes
12-16-2008, 07:22 PM
Nicholas - thanks for bringing up diluters - while they do use an automated syringe I was thinking of what's sometimes called an infusion pump. Here's a good sit covering the devices I'm interested in. http://www.kdscientific.com/products/infusion-pumps.asp and a nice brochure covering it - it's about 2 megs in size: http://www.kdscientific.com/downloads/catalog.pdf

I've used an automated syringe with a valve attached for moving liquids back and forth into an instrument, and it would take a bit of programming chops to use one of these. See http://www.kloehn.com/products/pumps.html The interface I've used on the Kloehn pump does not have any control on the flow rate, so it would not really be suitable for emulsion making as some provision needs to be there for setting the flow rate. And the infusion/syringe pumps I've seen usually have some adjustment in flow rate, both by choosing the volume of the syringe and also with the rate the plunger is set to move.

As to the pause and refill, as long as you are not using really huge volumes, you may be able to use a single syringe for the total volume being dispensed. Or, one could pre-load a couple syringes and manually load them in one after another.

It's similar to how PE showed us in the emulsion class at the Formulary last year to dispense larger volumes. We had about 70 ml to add to the emulsion over 10 minutes, so we loaded up 4 - 20 ml syringes and he used his "Model 1" human-hand syringe dispenser to add the solution to the kettle. While he did a good job of dispensing the solution at the rate needed, I'm looking to ways to automate things like this.

Nicholas Lindan
12-16-2008, 08:46 PM
Ah, now I see what you are looking for.

Yup, should work fine. Might have to modify an OEM module to take a 100ml syringe. I haven't used them, only diluters, which I have designed into clinical analyzers.

Another pump you might consider are the contrast media power injectors used for CAT scans - they usually have 100ml or so syringes - you would have to find one on the scrap market.

Ditto industrial dispense pumps - a glue or pigment dispenser might work. Though the flow rate isn't specifically controlled they usually dispense a fixed amount with each pulse - by controlling the pulse rate you can control the flow rate.