Lesson 15: What Makes a Good Peristaltic High-Pressure Hose?
Objective:
By the end of this lesson, you will understand the critical factors that contribute to the quality and performance of a high-pressure peristaltic hose. This includes an in-depth look at rubber composition, reinforcement layers, inner and outer layer properties, and the importance of specific materials like NR, NBR, EPDM, and CSM. We will also explore the unique manufacturing practices of MTG/RCME, which ensure superior hose performance.
15.1 Introduction to High-Pressure Peristaltic Hoses
High-pressure peristaltic hoses are designed to withstand the demanding conditions of industrial applications, where they are subjected to significant mechanical stress and varying chemical environments. The quality of these hoses is determined by multiple factors, including the composition of the rubber, the structure and arrangement of reinforcement layers, and the physical properties of the hose’s inner and outer layers. In this lesson, we will explore what makes a high-pressure peristaltic hose effective and reliable, with a special focus on the advanced manufacturing techniques used by MTG/RCME.
15.2 Rubber Composition
The type of rubber used in a peristaltic hose is foundational to its performance, particularly in terms of durability, flexibility, and chemical resistance. The main types of rubber used include:
15.2.1 Natural Rubber (NR)
NR is Suitable For:
Solvents and Alcohols
Acetone – Good compatibility with mild ketones
Ethyl Alcohol (Ethanol) – Handles alcohol-based solutions
Allyl Alcohol – Used in chemical synthesis and industrial applications
Air and Gases
Air Handling – Suitable for compressed air and gas transfer
Slurries and Mild Chemicals
Acryl Aryl Sulphonate Slurry – Used in chemical processing
⚠️ Limitations of NR in Peristaltic Pumps:
NR is NOT resistant to oils, fuels, and aggressive solvents.
It has poor resistance to ozone, UV, and oxidation.
Not ideal for handling strong acids or high-temperature applications.
15.2.2 Nitrile Rubber (NBR)
NBR is Suitable For:
Air and Gases
Air Handling – Good compatibility with compressed air
Suitable for non-aggressive gas transfer
Mild Alcohols and Surfactants
Ethyl Alcohol (Ethanol) – Can handle mild alcohol-based solutions
Alkylaryl Benzene Sulphonate – Commonly used in detergents and industrial surfactants
Mild Inorganic Chemicals & Salts
Alum (Aluminium Sulphate) – Used in water treatment and industrial applications
Aluminium Chloride – Used in chemical processing with moderate compatibility
⚠️ Limitations:
NBR is not resistant to many oils, fuels, and aggressive chemicals.
It is unsuitable for strong acids, ketones, and solvents.
Mechanical wear in peristaltic pumps can accelerate degradation.
15.2.3 Ethylene Propylene Diene Monomer (EPDM)
EPDM is Best Suited For:
Acids (Mild to Strong)
Acetic Acid (20%, 30%, 50%, 99%) – Suitable for different concentrations
Other mild acids (good general acid resistance)
Solvents and Ketones
Acetone – Handles ketones effectively
Other oxygenated solvents (excluding strong hydrocarbons)
Water and Aqueous Solutions
Suitable for water, condensate, and aqueous solutions
Great for high-temperature applications
⚠️ Limitations of EPDM in Peristaltic Pumps:
NOT resistant to oils, fuels, and most hydrocarbons
Poor compatibility with strong solvents and chlorinated compounds
May degrade in extreme mechanical stress applications with petroleum-based substances
15.2.4 Chlorosulfonated Polyethylene (CSM)
CSM is Best Suited For:
Acids (Mild to Strong)
Acetic Acid (20%, 30%, 50%) – Excellent resistance to organic acids
Other oxidizing and corrosive environments
Gases and Air Handling
Air – Suitable for compressed air and gas transfer
Weather-resistant applications (CSM has excellent UV and ozone resistance)
Alcohols and Mild Solvents
Ethyl Alcohol (Ethanol) – Compatible with alcohol-based solutions
Moderate resistance to certain industrial solvents
⚠️ Limitations of CSM in Peristaltic Pumps:
NOT resistant to oils, fuels, and most hydrocarbons
Limited resistance to some strong solvents
May degrade in high-temperature, high-stress mechanical applications
15.3 Binding to the Reinforcement
The effectiveness of a high-pressure peristaltic hose depends not only on the type of rubber used but also on how well the rubber binds to the reinforcement layers. Proper adhesion between the rubber and the reinforcement layers is crucial for maintaining the hose’s structural integrity under pressure.
15.3.1 Importance of Strong Binding
- Prevents Delamination: Strong binding ensures that the rubber layers do not separate from the reinforcement, preventing delamination, which can lead to premature hose failure.
- Maintains Structural Integrity: Good adhesion helps the hose maintain its shape and strength, even under high-pressure conditions.
15.3.2 MTG/RCME Manufacturing Excellence
- Uniform Rubber Composition: Hoses manufactured by MTG/RCME feature rubber that is pressed onto the reinforcement sheets, with all layers—including the rubber, reinforcement, and bonding layers—coming from the same rubber batch.
- Superior Binding: This uniformity ensures the best possible binding during the vulcanization process, resulting in a hose with exceptional durability and resistance to delamination. By using the same rubber batch for all layers, MTG/RCME enhances the compatibility and bonding between the layers, providing superior performance and longevity.
15.4 Reinforcement Layers
The reinforcement layers provide the necessary strength and flexibility to withstand high-pressure applications. These layers are typically made of synthetic fibers or steel and are designed to support the hose structure under stress.
15.4.1 Number of Reinforcement Layers
- Consideration: The number of reinforcement layers affects the hose’s ability to handle pressure. More layers generally provide greater strength, but they also increase the hose’s stiffness.
- Application: The number of layers is chosen based on the specific pressure requirements of the application.
15.4.2 Reinforcement Wrapping Angle
- Importance: The angle at which the reinforcement layers are wrapped around the hose affects its flexibility and pressure resistance.
- Optimal Angles: A balanced wrapping angle helps distribute the pressure evenly across the hose, reducing the risk of failure.
15.4.3 Distance Between Reinforcement Layers
- Significance: The distance between reinforcement layers influences the hose’s overall flexibility and its ability to absorb shocks and pulsations.
- Optimization: Proper spacing ensures that the hose remains flexible while still providing adequate pressure resistance.
15.5 Inner Layer Properties
The inner layer of a peristaltic hose is critical as it is in direct contact with the fluid being pumped. This layer must resist wear, chemical attack, and deformation.
15.5.1 Inner Layer Wall Thickness
- Consideration: The thickness of the inner layer must be sufficient to withstand abrasion and chemical exposure without compromising flexibility.
- Balance: A thicker wall provides better durability but may reduce flexibility. The optimal thickness depends on the specific application requirements.
15.5.2 Shore A Hardness of the Inner Layer
- Definition: Shore A hardness measures the hardness of rubber, with higher numbers indicating harder materials.
- Optimal Range: For the inner layer, the Shore A hardness should be selected based on the fluid’s abrasiveness and chemical properties. Typically, a hardness range that balances durability with flexibility is chosen.
15.6 Outer Layer Properties
The outer layer protects the hose from external damage, including abrasion, environmental factors, and physical impacts.
15.6.1 Shore A Hardness of the Outer Layer
- Function: The outer layer’s hardness affects its ability to resist abrasion and environmental wear.
- Optimal Range: A harder outer layer (higher Shore A hardness) is preferred for applications involving rough handling or abrasive environments, while a slightly softer layer may be used where flexibility is more important.
15.7 Dimensional Tolerances
Dimensional tolerances are critical for ensuring that the hose fits properly within the pump and operates efficiently.
15.7.1 Importance of Tight Tolerances
- Fit and Function: Tight dimensional tolerances ensure that the hose maintains its shape and fits correctly within the pump housing, which is crucial for maintaining consistent compression and flow.
- Quality Control: Ensuring that hoses are manufactured within specified tolerances is essential for maintaining the overall performance and reliability of the pump
15.8 Conclusion
A high-quality peristaltic hose is the result of careful consideration of multiple factors, including rubber composition, reinforcement structure, and the properties of the inner and outer layers. The advanced manufacturing practices of MTG/RCME, such as using the same rubber batch for all layers, further enhance the hose’s durability and performance. By understanding these elements, you can select hoses that offer the best performance and longevity for your specific application, whether it involves handling abrasive slurries, corrosive chemicals, or high-pressure fluids.
Open questions: These questions encourage learners to explore the factors that contribute to the quality and performance of high-pressure peristaltic hoses, with a focus on material composition, reinforcement, and advanced manufacturing techniques.
- How does the selection of rubber material (NR, NBR, EPDM, and CSM) impact the performance of high-pressure peristaltic hoses in demanding industrial applications?
- Why is Natural Rubber (NR) often preferred for abrasive applications, and how does it compare to NBR, EPDM, and CSM in terms of wear resistance and flexibility?
- What specific challenges does Nitrile Rubber (NBR) face in peristaltic pumps, and why is it not the best choice for handling oils and fuels under extreme mechanical stress?
- How does the resistance of EPDM to acids and high temperatures make it a strong candidate for chemical applications, and what are its key limitations in peristaltic pumping?
- What makes CSM a unique material for peristaltic hoses, and how does its resistance to ozone, UV, and chemicals contribute to its performance in industrial environments?
- Why is the adhesion between rubber and reinforcement layers critical in preventing delamination, and how does it affect the hose’s overall durability?
- How do the number of reinforcement layers and their wrapping angle influence the balance between flexibility and pressure resistance in a high-pressure peristaltic hose?
- What role does the inner layer’s wall thickness play in preventing abrasion and chemical attack, and how can improper thickness selection lead to premature hose failure?
- How does the Shore A hardness of both the inner and outer layers of a peristaltic hose impact its resistance to wear, chemical exposure, and mechanical stress?
- How do MTG/RCME’s advanced manufacturing techniques, such as using the same rubber batch for all layers, improve hose bonding, structural integrity, and overall longevity?