Peristaltic hose pumps and diaphragm pumps both serve to move liquids, yet they work in different ways – diaphragm pumps create suction with a vibrating membrane, while peristaltic pumps squeeze liquids in one direction through a hose.
Each type of pump offers unique benefits and disadvantage. Diaphragm pumps have more parts, so they can be more difficult for inexperienced users, while peristaltic hose pumps are easier to operate - yet they require more oversight to avoid maintenance issues.
Benefits and drawbacks of a diaphragm pump
This type of pump usually costs less to operate, as long as it is maintained properly. One reason for this lower cost is that diaphragm pumps harness more of the motor's energy; the pumping action relies on the forward push of the diaphragm, which allows the motor to briefly rest during the second half of the pump cycle. Because they rarely leak, diaphragm pumps work well for moving harsh liquids and chemicals. And, this type of pump can better overcome back-pressure in the line.
Still, they do have some negative characteristics – since a diaphragm pump relies on check valves with balls that must rotate freely, if the liquid is dirty or contains particulate material or gases, the pump must work harder to move it.
Worse, the pump may lose accuracy or fail to function if these valves become entirely clogged. And, diaphragm pumps may experience difficulty in overcoming back-pressure; adjusting the pump to achieve maximum stroke may help solve this problem. As well, most pump models have an adjustable inflow and feature bleed valves to release trapped bubbles.
The pluses and minuses of peristaltic hose pumps
Peristaltic pumps are easy to set up and use. They can also handle high back-pressure and viscous liquids, even dirty liquids containing many particles. Best of all, these pumps are easy to prime and are well-suited for almost any kind of liquid.
Yet, peristaltic pumps are not trouble-free, especially regarding the tubes and other parts which come into contact with liquids. During operation the motor never rests, which uses more electricity and can wear down the motor's components more quickly. The main drawback of this type of pump is the tubing itself – with constant squeezing, over time the tubing tends to lose flexibility, which lowers the feed rate and compromises the pump's ability. The most serious disadvantage of peristaltic pumps is their tendency to develop leaks in deteriorated tubing, which can cause costly damage to the pump or the environment. Makers of peristaltic pumps calculate the working life of their hose, yet pump users often underestimate the total time that the pump has been operating.
Peristaltic pumps are usually best for pumping viscous fluids containing many particles or gas bubbles under higher pressures, while diaphragm pumps are best for clear solutions or strong chemicals being pumped under moderate pressures.