ODE solenoid valves made with LATI technical compounds to ensure pressure resistance, electrical insulation, and long-term durability
Drinking water, Food Contact, High temperatures, Home Appliances and Consumer Goods, Industry
Drinking water, Food Contact, High temperatures, Home Appliances and Consumer Goods, Industrybyadmin

A complete range of PPS valves for managing food fluids and more.

Index:

2012: Reduction of Lead Content in Brass Products

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Growing concerns about toxic substances leaching into food and drinking water have led over time to a series of restrictions regarding the nature of many materials used in the food and beverage sector.

Among these is brass, which in 2012 came under scrutiny from surveillance bodies due to the presence of lead in some of its standard formulations. The copper and zinc alloy traditionally used for hot forging and subsequent machining is OT58 or CW614n, which contains approximately 3% lead to limit tool wear during milling and turning operations. A classic use of OT58 is in the manufacture of valves, taps, fittings, and other accessories used in managing drinking water and various food liquids.

The main problem is the gradual release of this heavy metal into water due to continuous washing action, especially during the initial phase of brass product use. This phenomenon, which can cause lead contamination at levels well above WHO recommended limits, has been studied by several international institutes and subjected to explicit restrictions (see for example the OEHHA’s Proposition 65 List).

The most immediate alternative to OT58 involves adopting alloys with very low or zero lead content, specifically to prevent any alteration of water’s organoleptic characteristics and, most importantly, health hazards. Low-lead brass alloys thus become the new reference for applications typically reserved for OT58 in the plumbing and thermosanitary sector. It’s the right time to explore innovative solutions.

 

A New Adventure for ODE Solenoid Valves

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The need to prevent lead and nickel release in food applications leads many traditional OT58 users to consider new material choices for manufacturing components and accessories.

Among the companies not hesitating to explore new solutions is Italy’s ODE (www.ode.it), a company based in Colico (LC) active in the design and manufacture of solenoid valves, coils, and fluid systems used particularly in automatic beverage dispensing (vending) and coffee machines.

For ODE, founded in the 1960s and traditionally loyal to brass, the transition to new materials represents much more than a technical and engineering challenge. It’s primarily a cultural and practical leap forward in a niche sector where reliability and reputation are highly significant, as the relationship with customers is direct and expectations for quality and technical support are extremely high.

 

Industry Requirements

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The typical design requirements imposed on valves are indeed very rigorous with no possibility for deviation.

First and foremost, the continuous contact with drinking water and other food fluids. The material must be compatible with this use and certified by accredited international bodies. It cannot release any substance that poses a threat to human health or could alter the organoleptic characteristics and nature of the beverage.

The second significant specification concerns the temperature of fluids present in the internal chambers of the valves. Vending machines typically handle water at 95°C for preparing hot beverages. At these temperatures, the robustness and integrity of the valve body must be guaranteed. Any fluid leakage through seals or pressure losses due to local deformations must absolutely be prevented and avoided.

From a mechanical perspective, the stresses are considerable due to the pressure imposed on the liquids. Although the infusion process typically requires 16 bar, ODE tests its devices at over 80 bar. The stress is applied both statically and in pulsating mode for an extended period, simulating the actual operating conditions of the solenoid valves.

As an element belonging to an electromechanical device, the valve body must be flame resistant with relevant UL flame retardancy certification.

Finally, life expectancy and maintenance frequency are fundamental, which in both cases should be comparable to or better than classic brass elements.

 

Selecting the Technopolymer for New Solenoid Valves

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Faced with such a complex combination of technical requirements and the risk scenario inherent in any pioneering operation, ODE’s design staff opted for a glass fiber reinforced polyphenylene sulfide (PPS) compound, LATI’s LARTON G/40.

The decision to adopt PPS for the innovative generation of technopolymer valves was made in agreement with LATI technicians following a careful analysis of possible alternatives, all rejected for various reasons: PP and POM for thermal limitations, PA for resin hygroscopicity, polyester for hydrolysis issues, PPA for dimensional constraints, PEEK for economic constraints.

The choice is supported by countless successful applications of PPS-based compounds in various industrial sectors and under extreme working conditions.

 The most interesting characteristic of PPS is certainly its remarkable resistance to high temperatures, surpassed only by PEEK and very few other polymers, which are more performant but also significantly more expensive and complex from a processing perspective.

Its particular chemical-physical nature and macromolecular structure make this polymer particularly suitable for injection molding of very complex geometries with thin walls. The differential shrinkage is minimal, allowing dimensional precision often precluded to other thermoplastic resins.

Extremely resistant to chemical attack from organic and inorganic agents, even at high temperatures, PPS is also non-hygroscopic, so its main properties are not deteriorated following prolonged exposure to water or steam.

Thanks to its intrinsic flame resistance, PPS does not require flame retardant additives that could irreparably compromise not only its mechanical properties but especially its suitability for contact with drinking water.

LARTON G/40 is a compound capable of structural performance suitable for the most extreme metal replacement operations thanks to its 40% short and thin glass fibers, a combination that optimizes the reinforcement-matrix interface allowing full exploitation of the reinforcement system. LARTON G/40’s elastic modulus exceeds 17 GPa with a breaking stress close to 200 MPa, values significantly higher than those of neat polymers and more than satisfactory when combined with appropriately designed geometries.

 

Design and Development

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The initial feasibility checks are conducted by ODE in collaboration with LATI through FEM analysis, to evaluate the stress state imposed on the material of each valve body during the application of test pressure at room temperature. The 80 bar, distributed on the internal surfaces of two and three-way modules, translate into local Von Mises stress peaks below the safety limit, set at 95 MPa following the introduction of a composite safety factor of 1.8. The resulting deformations are subject to careful evaluation to prevent leakage through sealing gaskets; calculations indicate that displacements under load are limited to a few hundredths of a mm.

As standard practice, laboratory tests are performed on the first prototypes – including up to 900 consecutive hours of operation – essential for fine-tuning the valve body geometry, molds, and production process. As soon as the tests are successfully completed, approval is given for mold construction.

ODE thus introduces, first to market, its Made in Italy PPS valve system that will quickly lead the company to become a market leader in its sector

 

A Complete Range of Technopolymer Valves

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Several years have passed since the first 21JP and 31JP proposals, and ODE’s catalog for the food solenoid valve market now includes many dozens of different solutions in PPS, PSU, POM, and other technopolymers.

The characteristics of reinforced PPS allow the management of hot food-grade water at 95°C for both standard valve bodies and NSF61 certified elements, the latter used for example in freestanding beverage vending machines or in the OCS sector machines.

Material testing reveals several additional strengths. Firstly, a lower tendency for limescale formation compared to traditional elements, benefiting reliability and life expectancy of equipment in the market. PPS valve bodies also allow considerable weight reduction compared to metal since LARTON G/40’s density is 1.67 g/cc compared to brass at 8.73 g/cc. It also enables reduced heat dissipation and energy consumption due to the polymer’s lower thermal conductivity compared to brass.

All these aspects allow ODE valves to successfully establish themselves in the HoReCa sector (Hotellerie Restaurant Catering) where beverage dispensing must meet the highest quality standards, including precise control of hot water flow, pressure, and temperature.

Modern ODE valves in PPS can safely transport other fluids as well, such as steam at 140°C, inert gases, compressed air, and food liquids. ODE’s technopolymer systems thus find successful application in sectors beyond vending, including pneumatics and industrial automation , medical, and sterilization.

Particularly in the food & beverage sector, the success of technopolymer solenoid valves is consolidated by compliance with international food certifications.

A completely Made in Italy success story, strongly driven by the synergy of leading companies in their respective sectors.