About Peristaltic Pumps

What are Peristaltic Pumps and How Do They Work? - Video



About Peristaltic Pumps Video Summary

The Peristaltic Pumps is extremely useful type of pump. Because of the evolving technology of this positive displacement pump with its cross-industry, multi-application usages and scalability from process to lab to plant make it the fastest growing type of pump in the market.

This video explores what a peristaltic pump is and how it functions. Additionally, it describes several applications in which peristaltic pumps are easily used, the sorts of available tubing types and sizes including options on chemical compatibility and driver speed, and pump maintenance.



About Peristaltic Pumps - Video Transcript

In this video, Colin from Cole Parmer is going to be talking about peristaltic pumps. So, take us away. Thank you very much for that introduction. Peristaltic, peristaltic – What


A peristaltic pump, what is it? When would you consider this?

A peristaltic pump is a very basic sort of pump. The motion is peristalsis. So, it’s like the esophagus in the body. Imagine a long tube, you squeeze that tube. You move along and you release it. That’s the basis of the motion. And then if you do that several times you suck things in, move them along the tube, and release them. So, the pump itself is the tube. The motion is a low shear, it is a very gentle motion. This is the tube running through a pump head. If you look at that pump down there, the small down in front of me, that’s it. Open the pump head you can see the tube running through, that’s what we call the pump head. So, if we come back to here, that is the pump head. That is the tube running through the pump head. What we have is three rollers on this pump head. So, each roller is squeezing the tube and moving along and releasing creating ‘pockets’ of liquid within the tube. We defined in another presentation the liquid as being anything from water to toothpaste and many variations in between. If we look at how this grabs the liquid and moves it along (and the roller must roll on the tube to move it along), it’s a positive displacement pump. This technology positively displaces (or moves) one slug of liquid each time. Each rotation of that head moves three slugs of liquid. Those three slugs of liquid are one rotational displacement. The pump is the tube. The head, the pump head is how we squeeze the tube and move the liquid along it. The rest is the control. Look at the table. We have two sizes of pumps on here. But the pump is the tube at the front. We then have the pump head that squeezes the tube and we have the control system. From basic controls like variable speed control, which is on the smaller one, to process drives which are computer compatible. We have the same on the smaller units. They are laboratory scale or a finer scale. We do modular ones, which means you have the pump and motor separate from the control. But they are a very variable control. If I jump back to the first slide, one of the major advantages of the peristaltic pump is high accuracy and dosing. This is because we are looking at these small ‘pockets’ and we can control them accurately. If you are pumping ink to a printer, for example; within big industrial printing machines you need specific amounts of ink and you need to be able to adjust the amount of ink depending on how fast the printer is running. You can have a peristaltic pump that can pump the ink and use the tube so you have color containment. You don’t want to mix colors until they get to the print head. Otherwise the effect is spoiled. There’s one tube running from a source container to the tray where the ink sits. If the machine speeds up the pump can react to that and speed up. It works very well.

The rollers and the heads, these are all components of the pump head, and affect the way the pump works. But the tube is the pump. These pumps are the fastest growing within the positive displacement pump market.


Can these pumps dry run?

Dry Running is an interesting concept and yes, they can. Dry run means to run without any liquid in it. If you have pumps where you have metal to metal face and things like that, no. They can become damaged. These pumps, one of the distinct advantages is they can dry run. Because you have a roller reacting on a tube, squeezing on a tube, it can do that all-day long. There are no issues with metal to metal surfaces. There are no issues of unusual heat build-up. So, they can dry run. It’s very useful if you want to transfer, in a chemical environment liquid, from a drum to another drum. You can put the pump in and walk away. Because when it’s finished pumping the liquid across you don’t have to be there to switch it off. It’s useful, because you don’t need to have an operator standing watch. With other technologies, you would have to the operator constantly there. It’s a distinct advantage.


Another major benefit for these pumps is they are low shear.

The shearing is how the liquid moves against itself. And if you have something that has a low shear requirement, it means it’s delicate. If you move it too fast you damage it. The way to describe that is that if you had a cell culture that you needed to move very gently. You’ve grown something that you need to move it to another area, if you move that too fast through other types of pump technology you can bash them and destroy them. If you move them gently you won’t damage them. Another example, that we spoke about in another video, food processing. Soups and things like that. If you move soups in a tube gently they look the same when they come up as they did when they went in. A peristaltic pump can do. If you move them too fast or through a rotational pump, something like a centrifugal, you liquidize the lot. If you’re selling something, that’s a critical point for how it must turn out where quality of presentation is important. A lot of companies that make ready foods pump to filling trays. It affects the quality. It does make a difference.


What are the maintenance requirements for a peristaltic pump?

This is one of my favorite points, minimal. The wearing component is the tube. It’s a consumable, so you will have to change it. But that’s the only item. The tubes can get up to ten thousand hours of life of certain tubes and certain conditions, which is several years run time. The motors and the pump heads, I’ve know them to go on more than ten years. The actual pump drive and control gives them very good working life, doesn’t have any issues. One of the easiest things to say, if you look at the smaller pump, the maintenance is quite easy. Close the pump head, now open the pump head and remove the tube. Just lift it out. Now put the tube back in and close it. You’ve just done the maintenance for a peristaltic pump. It’s as easy as that. My five-year-old daughter does that. It’s very basic and easy. We have another pump head here, which is called a high-performance pump head. So, it’s the same thing: unload, remove the tube, and refit another tube. That is your maintenance. They require minimal maintenance and because your process is contained within the tube, you’re not breaking process. From a hygienic point of view, you are not letting ingress of the outside, inside or the inside to go outside. You’re maintaining this hygienic sterility. You can use them as single-use system, take it and throw it away. Put in a new tube in and you’re clean again. You can have many different tubes of many different variations.

It is a wonderful pump; looking at the accuracy you can get, the control with dispense because you can have it do a repeated expense over an extended period. If you wanted to dose it into a production line, if you wanted to put some coloring into a food stuffs like dog biscuits for example – how do you think the coloring goes into those dog biscuits? In a line producing the biscuit dough there would be one sort of pump pumping that and then this would feed it the coloring to turn it into a dog biscuit.


What if You want to Increase Your Process?

That is valid point and good point with the peristaltic pumps. Increasing the process (increasing the amount you pump) while making the process from lab scale to product plant is easy with peristaltic pumps, because it’s the size of the tube. Their positive displacement so we just put a bigger tube. Again if we look at the two pumps on the table, one has a small tube and then to do more you just have a bigger tube. The pumps go in speeds of naught point one RPM to 600 RPM on the smaller. The larger ones are lower speed at their top end, because it’s about squeezing the tube and allowing the tube to reopen and reform. If you do it too fast you wouldn’t allow the tube to reopen.


Is This an Evolving Pump Technology?

I’m glad you asked the question. It’s an evolving technology, because the secret of this pump is the tube. There is a range of pump tubing. They can handle different liquids; some have higher hygienic ratings than others, they are approved for pharmaceutical grades to food grades. Some can handle chemicals. This shows the different tubes and the tubing compatibility, and the sizes of tubes. We are not limited by these here. We have numerous options within our range. We have stainless steel drives. We have bigger pumps, we have the BT Range which can go up to 45 liters per minute. We have modular units, which is useful in a process environment or lab-scale environment if you want to put driver pump in a fume cupboard or a fume hood, but you can have the control outside. There are options to