How to Accurately Select Industrial Hose Specifications? Medium, Temperature, and Pressure are All Essential
Industrial hoses, as one of the core consumables in industrial production, achieve media transportation, equipment connection, and pressure transmission through their excellent performance. However, due to the significant differences in materials and conditions in different industrial production scenarios, selecting a suitable industrial hose is not easy. Improper selection can not only lead to decreased efficiency but also pose safety hazards. So, how do you select the appropriate inner diameter and wall thickness of an industrial hose based on the characteristics of the medium, operating temperature, and pressure requirements? This article will provide a comprehensive analysis of the core elements and process of industrial hose selection.
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I. Specifications and Classifications of Industrial Hose
Before understanding the selection rules, we need a comprehensive understanding of industrial hoses. Industrial hoses can be divided into the following main types according to their materials and application areas:
1. Rubber Hose
Main materials include natural rubber, nitrile rubber, fluororubber, etc., widely used in automobiles, machinery, and other fields, possessing excellent oil resistance, high temperature resistance, and corrosion resistance.
2. Plastic Hose
Primarily made of polyvinyl chloride (PVC), polyurethane (PU), and polytetrafluoroethylene (PTFE), suitable for conveying chemical media, food-grade fluids, and high-pressure environments.
3. Composite Material Hose
Typically designed with layers, the outer layer is a protective coating, and the middle layer is a reinforcing material. This type of hose combines the properties of multiple materials and is suitable for harsh environments such as mines and oil fields.
4. Metal Hose
Including stainless steel corrugated hoses and metal-reinforced flexible hoses, suitable for high-temperature, high-pressure environments and conveying corrosive media.
Each type of hose is further divided into different specifications and models according to its application and performance, generally including parameters such as inner diameter, outer diameter, working pressure, water flow rate, and temperature resistance range. Accurately understanding these parameters is the foundation for subsequent selection.
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II. Selecting the Appropriate Industrial Hose Based on the Media
The properties of the media directly affect the material and structural requirements of the hose. Inappropriate media selection may lead to hose corrosion, accelerated wear, or even leakage. Therefore, the following characteristics of the transported medium must first be determined:
1. Chemical Properties of the Medium
- Acidity/Alkalinity: Select a hose made of a material with high corrosion resistance. For example, when transporting acidic or alkaline liquids, a hose with an inner layer of fluororubber or polytetrafluoroethylene (PTFE) can be selected.
- Solvents or Oils: Nitrile rubber or fluororubber hoses with excellent solvent resistance are suitable.
2. Viscosity of the Medium
Viscous substances (such as greases and asphalt) have slower flow rates, requiring a low-friction coefficient inner wall design. The inner diameter should be adjusted according to the flow rate.
3. Particle Content
Mediums containing particles or powders cause greater wear on the inner wall of the hose. A steel wire-reinforced hose with high wear resistance can be selected to prevent rapid aging of the hose wall.
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III. How to Select the Appropriate Hose Material Based on the Medium Temperature
Temperature is one of the key factors affecting the performance of industrial hoses. If the temperature exceeds the hose's tolerance range, it may cause material aging, softening, or cracking. Therefore, it is essential to select products with suitable temperature resistance based on the actual working environment.
Temperature Range Classification:
1. Normal Temperature Environment
For operations between 0℃ and 60℃, conventional PVC or ordinary rubber hoses are sufficient.
2. High Temperature Environment
When the fluid temperature exceeds 70℃, heat-resistant hoses are recommended. For example, when transporting steam, high-temperature resistant hoses specifically designed for steam transport should be used, made of EPDM (ethylene propylene rubber) or silicone rubber.
3. Low Temperature Environment
For environments with operating temperatures below -20℃, materials with strong cold resistance must be selected, such as polyurethane or special rubber hoses, to prevent the hose from becoming brittle at low temperatures.
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IV. Selecting the Inner Diameter and Wall Thickness of the Hose Based on Pressure
Pressure conditions are a core parameter determining the safety and long-term use of the hose. Different pressure ranges directly affect the inner diameter and wall thickness of the hose.
Hose Selection by Pressure:
1. Low-Pressure Hose (<10 kg/kg)
Thinner-walled hoses can be selected, but sufficient toughness should be ensured to prevent deformation under pressure.
2. Medium-Pressure Hose (10-40 kg/kg)
Medium-thicker-walled designs with added braided layers are recommended. Examples include medium-pressure hoses commonly used in pneumatic equipment or hydraulic systems.
3. High-Pressure Hose (>40 kg/kg)
Steel wire-reinforced industrial hoses with a multi-layered internal structure are recommended. Especially for hoses used in hydraulic transmissions, ensure the inner diameter is perfectly matched to the flow rate to avoid energy loss.
Precautions:
- Increased wall thickness may reduce flexibility; therefore, the bending radius of the hose must be considered in high-pressure applications.
- The pressure limit must be at least 1.25 times the operating pressure.
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V. Calculation Method for Matching Inner Diameter and Flow Rate of Industrial Hose
The inner diameter of the hose should be calculated and selected based on the actual flow rate requirements. If the inner diameter is too small, the operating pressure will increase, easily increasing equipment wear; if the inner diameter is too large, it may lead to a decrease in flow rate. The following are common hose diameter selection formulas and methods:
Common Formula Calculation:
$$ Q = V \times A $$
Where Q is the flow rate; V is the flow velocity; A is the cross-sectional area of the hose (which can be calculated using $\pi \times r^2$, where r is the inner diameter).
Example: If the required flow rate is 2 m/s, and the required flow rate is 5 cubic meters/hour, the inner diameter can be determined through reverse calculation.
Practical Selection Recommendations:
- For gaseous media, it is recommended to choose a smaller inner diameter to ensure sufficient pressure.
- For liquid media, especially substances that are not easily flowable, the inner diameter can be appropriately increased to reduce flow resistance.
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VI. Factors Affecting the Lifespan of Industrial Rubber Hose and Maintenance Recommendations
The lifespan of a rubber hose depends not only on the type selected but also on subsequent usage and maintenance. Here are some key recommendations:
1. Avoid Overloading
The lifespan of a rubber hose is closely related to pressure and temperature loads. Always ensure that the operating conditions of the hose do not exceed its rated values.
2. Regular Cleaning and Maintenance
Remove accumulated impurities and contaminants from the inside and outside of the hose, especially after conveying high-viscosity substances.
3. Storage and Protection
Industrial rubber hoses should be stored in a dry and well-ventilated environment, avoiding direct sunlight to prevent rubber oxidation.
4. Inspect for Aging and Damage
Perform a visual inspection of the hose surface regularly. If cracks, bulges, or hardening of the material are found, replace the hose immediately.
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Summary: Scientific and Rigorous Selection of Industrial Hose
Industrial hoses come in a complex and diverse range of specifications. When purchasing, users must fully consider key factors such as the properties of the conveyed medium, operating temperature, and pressure conditions, while also calculating the hose diameter based on the actual flow rate. Proper hose selection not only improves production efficiency but also reduces losses and costs. Following the guidance provided in this article, you will be able to easily find the best industrial hoses for your production environment, helping industrial production operate more efficiently, safely, and economically.
