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Temperature Control Hoses for Mold Cooling: Selection, Use, and Installation

Temperature control hoses connect temperature control circuits with tools and molds. For mold cooling, **material resistance**, **pressure and temperature resistance**, and compatibility with heat transfer fluids (water, glycol, thermal oil) are crucial. This page provides precise information on materials (PVC, FKM, EPDM, silicone, PKR/NBR), designs, connections, seals, and typical damage patterns, as well as concrete application examples for selection and installation.

Materials and Typical Properties

**PVC** hoses are suitable for low to moderate temperatures and offer good chemical resistance to aqueous media. They are cost-effective, flexible, and frequently used in **cold temperature control** applications. **EPDM** provides excellent resistance to hot water and steam, as well as many alkaline solutions, and typically withstands temperatures up to ~150 °C. EPDM is often the first choice when hot water temperature control systems or steam purging are relevant. **FKM** (Viton) offers excellent resistance to organic solvents, oils, and higher temperatures up to ~200 °C. FKM hoses are suitable for temperature-controlled circuits with heat transfer oils or in environments where aggressive process media occur. **Silicone** hoses are very flexible, biocompatible, and are used for high temperature fluctuations and overheating requirements; depending on the type, silicone can handle continuous operating temperatures up to ≈200 °C, but shows lower abrasion resistance. **PKR/NBR** rubber hoses offer good resistance to mineral oils and are inexpensive, but are limited at high temperatures compared to FKM.

Designs, Wall Construction, and Pressure Ratings

Temperature control hoses are available in simplex and duplex versions, with smooth or textured surfaces, single or multi-layered with fabric inserts for pressure reinforcement. For higher pressures, reinforced hose types with textile fabric or spiral inserts are necessary. Common nominal pressure ratings range from 6 bar to 25 bar; the choice depends on pump pressure, height differences, and safety factors. In addition to pressure resistance, wall thickness also influences heat transfer and flexibility: thinner walls improve heat transfer, while thicker walls increase service life and impact resistance.

Connections, Fittings, and Seals

For mold cooling, the following connection systems are common: screw couplings, quick couplings, press fittings, and cone fittings. Metal connections (brass, stainless steel) are standard; for media-critical applications, **stainless steel** is recommended to prevent corrosion and particle contamination. Seals are selected according to the medium: EPDM or NBR seals for water/glycol, FKM seals for oils and aggressive media. For quick couplings, high-quality O-rings are crucial; material fatigue can be minimized by proper lubrication during assembly and regular replacement intervals.

Temperature and Media Compatibility

The selection of the temperature control hose depends on the maximum system temperature range and the chemical composition of the heat transfer fluid. For water/glycol circuits, EPDM and PVC types are common. FKM is recommended for oil-based media and higher temperatures. Silicone is useful for frequent temperature changes and when low toxicity is required. When using additives (corrosion inhibitors, biocides), compatibility with O-rings and the inner hose material must be checked to avoid swelling or embrittlement.

Diameter, Lengths, and Pressure Drop

The inner hose diameter determines flow rate and pressure drop. Small diameters increase flow velocity and thus pressure drop; for larger molds or lower pump performance, larger nominal sizes are chosen to optimize heat transfer rates. Calculate pressure drop and required pump power based on volume flow, pipe length, and hose roughness value. For long pipe runs, increasing the cross-section or using smooth inner surfaces is recommended to reduce energy losses.

Installation, Routing, and Assembly Instructions

Hoses should be routed without sharp bends; the manufacturer's minimum bending radius specification must be observed to avoid kinking and premature wear. Fastenings should be chosen to exclude localized stresses and chafing. For flexible connections, anti-kink spirals or hose guides are recommended at transition areas to the mold. For metal connections to rubber, galvanic protection and a suitable clamp made of corrosion-resistant material should be used. Purge and vent openings should be provided at the lowest points to avoid air pockets that reduce cooling performance.

Maintenance, Service Life, and Typical Damage Patterns

Temperature control hoses age due to thermo-oxidation, hydrolysis, abrasion, and chemical attacks. Typical damages include cracks at bending radii, internal delamination, swelling due to incompatible additives, and wear at connection points. Regular visual and pressure checks, replacement of seals, and a log of operating times extend the service life. For critical applications, preventive replacement after defined operating hours and documented pressure tests after maintenance intervals are recommended.

Selection Criteria: Quick Summary

* Choose the hose material primarily based on medium and temperature; dimension inner diameter and pressure rating based on volume flow and pump performance.

Practical Examples

Example 1: Injection molding tool with fine cooling channels. Use: EPDM hoses DN10 with fabric insert, nominal pressure 16 bar, stainless steel connections with EPDM O-ring. Installation: short, radius-safe routing, kink protection near the mold, regular pressure testing every 6 months. Result: constant temperature control, low downtime due to material resistance to hot water. Example 2: Temperature control circuit with heat transfer oil. Use: FKM hoses DN16, smooth inner wall, nominal pressure 20 bar, stainless steel screw connections with FKM seals. Installation: thermally insulated hose lines to minimize heat loss, filter before pump inlet to protect against particles. Result: long-term resistance to oil additives and stable process heat. Example 3: Laboratory circulation with frequent temperature changes. Use: Silicone hoses DN8, flexible, low storage effect, quick couplings with NBR O-rings for low chemical stress. Installation: short, easily accessible hose segments for quick disassembly and cleaning. Result: fast response times during temperature control, low risk of contamination. Further application examples and technical scenarios can be found under [Application Examples](https://maku-industrie.de/anwendungsbeispiele) and detailed background information under [Technology](https://maku-industrie.de/technik).

Testing and Quality Requirements

Temperature control hoses should undergo a pressure and leak test before installation. Important test values are nominal pressure, burst pressure, and temperature resistance. Certifications or material data sheets (TDS) provide information on softening temperature, Shore hardness, tensile strength, and chemical resistance. For safety-relevant applications: demand documented origin of materials and batch traceability.

Sustainability and Spare Parts

Reducing material wear and the ability to replace connection or sealing components separately extend the service life of the system and reduce downtime costs. Recyclable materials and durable metal connections are economically advantageous. Spare parts such as O-rings, clamps, and quick coupling seals should be kept in stock to minimize downtime.

Procurement and Technical Support

When purchasing, pay attention to complete technical specifications: material, inner diameter, wall thickness, nominal pressure, temperature range, permissible bending radius, connection type, and test certificates. For customized requirements, we offer advice on material selection, design, and installation. Technical details and product lists can be viewed in our shop at https://maku-industrie.de/shop/de/rectus/formenkuehlung/schlaeuche/.

FAQs

**1. Which material is best for hot water temperature control systems?**
For hot water temperature control systems, **EPDM** is usually the best choice due to its resistance to hot water and steam; for higher temperatures or oil-containing media, **FKM** is preferable. **2. How do I determine the correct inner diameter?**
The inner diameter depends on the desired volume flow and the maximum permissible pressure drop. Calculate the volume flow based on mold size and required cooling capacity; then select a diameter that keeps the pressure drop within the pump capacity. **3. How do I avoid premature hose damage at connection points?**
Avoid sharp bends, use kink protection and suitable clamps, choose corrosion-resistant connections (e.g., stainless steel), and replace O-rings at regular intervals. Additional measure: use filter systems to keep solid particles away.