Peristaltic pumps themselves feature a fluid that only contacts the pump tube without contaminating the pump body, allowing for largely aseptic transfer. They are self-priming, reversible, and highly reliable. In addition, peristaltic pumps are suitable for applications where isolation of the product from the environment is essential, such as pumping abrasives, corrosive or/and viscous liquids. Peristaltic pumps are used in a wide range of applications but are not limited to Medicine, Chemical processing, Pharmaceutical production, dosing systems, food manufacturing, beverage bottle fillings Aquarium water supply, and wastewater treatment.
Peristaltic pump hose as an important part of the peristaltic pump in the liquid transmission plays an important role, so what kind of material should be used for peristaltic pump hose to transmit a variety of different fluids, what is the difference between the diameter and wall thickness of them? Next to analyze the hose in the selection some factors should be considered.
I. Hose Characteristics
1. pump tube has a certain elasticity, that is, the hose radial compression can quickly restore the shape (Shore hardness: 40 ~ 80).
2. With a certain degree of wear resistance
3. The ability to withstand certain pressure
4. Low adsorption (good airtightness)
5. Good temperature resistance, not easy to age
6. Anti-corrosion and non-swelling
7. Low precipitates
II. Chemical Compatibility
Hose in the transmission of different fluids should show a certain excellent chemical performance, known as chemical compatibility. Such as low adsorption, good temperature resistance, not easy to age, not swell, corrosion resistance, low precipitates, etc. Ordinary pipes have only general contact with chemical substances, while peristaltic pump tubes are in contact with chemical fluids under working conditions, so the level of chemical compatibility of ordinary pipes cannot be equated with the level of chemical compatibility of peristaltic pump tubes. For all types of transfer solutions, peristaltic pumps have appropriate hoses to suit the requirements. The user should check each chemical in the solution to ensure it is compatible with the chosen pump tubing.
Chemical compatibility test: take a section of a sample tube, record its weight, diameter, and length parameters, soak it for at least 48 hours, remove the sample tube, use a medium, soak it for at least 48 hours, remove the sample tube, wash and dry it with water, re-measure its weight, diameter, and length and observe the changes; also check whether the hose is soft or brittle. If there is a change, the hose is chemically affected by the fluid, i.e. the hose is not compatible with the fluid. Samples of each candidate pump hose should be placed in the actual factory environment for a trial run and the test results closely observed. If there is no discoloration, swelling, cracking, loss of flow, or other signs of deterioration of the pump hose after the test run, it is proven to be compatible with the fluid.
Back pressure occurs when a pump pushes fluid through a filter, pushes fluid through a flow meter or valve, or pumps fluid into a pressure reaction vessel. The application of peristaltic pumps is limited by the pressure performance of the hose. If the system pressure exceeds the hose pressure, the hose will expand, resulting in excessive hose wear or hose rupture. Factors affecting hose pressure are material, the ratio of diameter to wall thickness, etc.
Hose to adapt to the working temperature range the user should consider the factors. Different materials have different temperature properties. Some pipes, such as silicone rubber, have a wide temperature-carrying range and are suitable for high and low-temperature processes; some pipes are only suitable for a smaller temperature range. Therefore, before selecting piping, the user should first find out the maximum and minimum temperatures in the system and then ensure that the selected pump pipe will work safely within this temperature range.
The size of the hose directly affects the flow rate. The inner diameter of the hose determines the flow rate, which is proportional to the flow rate. Wall thickness affects the compression and bounce ability of the hose and has a significant impact on the life of the hose.
The use of transparent pipes depends on whether the operator needs to see the fluid in the pipe at all times and whether the fluid is sensitive to light. If the operator needs to observe the fluid, bubbles, particles, contamination, etc. in the pipe at all times, then Tygon transparent pipes should be chosen, such as polyethylene or silicone rubber If the solution should not be exposed, then opaque pipes should be chosen.
For some gas-sensitive fluids, such as fluids prone to oxidation or anaerobic cell cultures, the user should consider the permeability of the tubing. In general, silicone tubing has a high degree of permeability. Therefore, for fluids that are not suitable for exposure to gases, less breathable tubing should be selected
Where hoses are used for relevant applications, they can be certified as such. For example, the United States Pharmacopoeia standard USP, the European Pharmacopoeia standard EP, the United States Food and Drug Administration standard FDA, the United States Department of Agriculture standard USDA National Sanitation Foundation standard NSF.
VIIII. Service Life
Different hoses are resistant to repeated squeezing by rollers and have different friction capabilities. Different pipe types, pipes, pump heads, and operating speeds have different life spans. Choose a long-life, thick-walled pipe, and high flow rate pump to run at a lower speed to get a longer hose life.
X. Flow Rate Range
Each peristaltic pump hose corresponds to a fixed speed range and we select the appropriate hose according to the flow range required by the customer.
I. Saint-Gobain Rubber Tube
Excellent mechanical strength, autoclavable, stretchable, non-toxic, nonhemolytic
Continuous operating temperature: -60°C to + 135°C
Hardness: 64 A
Compatible with most CIP solutions and SIP
Breathability: 80 (for nitrogen test, the higher the value, the better the tube breathability, and vice versa.
UV resistance: A
Ozone resistance: B
Resistance to acids and alkalis: average
Pump tube service life: 1000 hours (this value is provided by Saint-Gobain and is for reference only)
Certification: USP Class VI, FDA, NSF, ISO 10993
II. MasterFlex Viton Tube
Viton is strong, resilient, and flexible, and provides excellent resistance to corrosive liquids such as acids, alkalis, and some aggressive chemical solvents
Continuous operating temperature: -32°C to +204°C
Hardness: 75 A
Ultra-pure, non-toxic, excellent chemical inertness
Breathability: low breathability
UV resistance: A
Ozone resistance: A
Resistance to acids and bases: strong acids and bases (e.g. 98% concentrated sulphuric acid), some corrosive organic solvents (e.g. chloroform)
Pump tube service life: 500 hours
Opaque black color helps protect the light-sensitive fluid
Certification: FDA and ADCF compliant
III. Silicone Tube
A translucent medical/food grade tubing that is odorless, non-toxic, autoclavable, stretchable
Continuous operating temperature -50°C to +200°C
Hardness: 55 A
Meets FDA standard, high sterility
Anti-thermal oxidation, ozone Aging, light aging, and weather aging
Platinum cured for reduced residual levels of siloxanes and other volatiles
Reduced spallation than a rubber tube
The same hose peristaltic pump special tube and the ordinary hose is the biggest difference in the material and service life, peristaltic pump transmission of fluid relies on the roller extrusion for fluid absorption and propulsion. Because of this special transmission method, hose life is also affected by this.
When the pressure is higher, the greater the pressure, the more damage to the hose, because most of the working environment of peristaltic pumps need to work for long periods, so the requirements of the hose are also more stringent than an ordinary hose. The inner diameter and wall thickness requirements are very high, the dimensional error requirements usually reach five percent.