The solenoid valve for water represents an essential component in the automation of high-pressure washing systems, enabling precise electrical control of water flow. These electromechanical devices allow for automatic opening or closing of water lines through electrical impulses, eliminating the need for manual intervention and enabling integration into fully automated systems. In the industrial cleaning sector and car-wash facilities, where operational efficiency and intelligent resource management are fundamental priorities, solenoid valves assume a strategic role in the design of modern and high-performance systems. Emiltec offers a selected range of high-quality valves, specifically designed for professional applications requiring reliability, durability, and consistent performance. In this in-depth guide, we will explore the operation of solenoid valves for water, the types available for high and low pressure, selection criteria, and practical applications in various industrial contexts.
A solenoid valve for water is an electromechanical device designed to control fluid flow through a conduit by means of electrical actuation of a valve. The operating principle is based on the use of a solenoid, an electromagnetic coil that, when energized, generates a magnetic field capable of moving an internal ferromagnetic core.
The valve body constitutes the main housing and contains the flow closure system. Typically made of brass, stainless steel, or technical plastic materials based on specific applications, it ensures hydraulic sealing and resistance to operating pressures. The choice of material is determined by fluid characteristics, operating pressure, and environmental conditions.
When the electromagnetic coil is powered with the appropriate voltage (typically 12V DC, 24V DC, 24V AC, or 220V AC), the generated magnetic field attracts the movable core, which in turn raises or lowers the internal shutter, allowing or blocking water passage. The speed of response and precision of movement make solenoid valves ideal for applications requiring timed or sequential controls.
Direct-acting solenoid valves operate with the solenoid directly moving the shutter, without the need for pressure differential. This design makes them particularly suitable for applications with high pressures and contained flow rates, as in the case of high-pressure solenoid valves used in car-wash systems.
Indirect-acting or pilot-operated solenoid valves instead use the fluid pressure itself to facilitate complete valve opening. The solenoid opens a small pilot orifice that creates a pressure differential, allowing the fluid to lift the main diaphragm. This principle allows managing larger flow rates with reduced power coils, making them more economical and energy-efficient for low-pressure applications.
In the Emiltec catalog, solenoid valves specifically designed for different pressure regimes are available, each optimized to ensure optimal performance under its own operating conditions.
High-pressure solenoid valves are direct-acting devices designed to work with water under high-pressure conditions. The 2-way high-pressure solenoid valves available at Emiltec, manufactured by the Italian brand ACL, allow for closing or opening a line and are configured as normally closed (NC), meaning that in the absence of electrical power the valve remains closed, blocking flow.
These devices typically find application on car-wash washing modules that manage various utilities and on small vehicles dedicated to urban cleaning. The construction robustness and selected materials guarantee reliability even under intensive use conditions with frequent opening and closing cycles.
Low-pressure solenoid valves with indirect actuation represent the ideal solution for applications where operating pressures are contained but required flow rates are high. Designed to work with water, these solenoid valves allow for closing or opening a line and are also configured as normally closed.
This type of solenoid valve typically finds application on car-wash washing modules that manage various utilities and on small vehicles dedicated to urban cleaning. The available fitting sizes (typically 1/2" and 3/4") allow managing significant flow rates while maintaining contained pressure drops.
The normally closed (NC) configuration offers significant advantages in terms of safety: in case of power interruption, the valve automatically closes, preventing water waste or accidental flooding. This characteristic is particularly appreciated in automated systems where flow management must be guaranteed even under abnormal conditions.
The appropriate selection of a solenoid valve for water requires analysis of multiple technical and operational factors. An inadequate choice can compromise system performance or cause premature component failure.
The first parameter to consider concerns the operating pressure values of the system. It is essential that the solenoid valve be sized to withstand the maximum operating pressure with an adequate safety margin. High-pressure solenoid valves can typically handle pressures up to 100-150 bar, while those for low pressure are designed for applications up to 10-15 bar.
The required flow rate determines the nominal diameter of the fittings. Solenoid valves with too small a passage cause excessive pressure drops and limit overall system performance. Common diameters range from 1/8" for minor applications up to 1" for higher flow rates, with 3/8" and 1/2" configurations representing the most widespread standards in washing systems.
The supply voltage must be compatible with the system's electrical system. Standard available voltages include 12V DC for mobile or battery-powered applications, 24V DC for industry and automation, 24V AC for specific applications, and 220V AC for direct connection to the electrical grid.
Solenoid valves powered by direct current (DC) generally offer faster response times and more stable current draws, making them preferable for applications requiring precise and frequent controls. Alternating current (AC) versions are simpler to integrate into existing systems but may present greater vibrations during operation.
The fluid type and its operating temperature must be compatible with the materials of the internal seals. NBR (nitrile rubber) seals are the standard for cold and lukewarm water up to 60-70°C. For applications with hot water or higher temperatures, seals in special materials such as Viton (FKM) or EPDM are necessary, which guarantee sealing and durability even at 90-120°C.
Solenoid valves for water find application in numerous professional washing contexts, where they contribute to process automation and operational efficiency optimization.
In automatic car-wash systems, solenoid valves manage the sequence of different washing phases. Each phase (pre-wash, shampoo, rinse, wax, polish) requires activation of specific water or chemical product lines. Solenoid valves allow programming customized sequences, optimizing consumption and ensuring consistent and repeatable washing results.
Integration with control systems such as electronics or PLC (Programmable Logic Controller) allows creating fully automated systems where the operator simply selects the desired program. Solenoid valves then execute the programmed sequence with millimetric precision in opening and closing times.
In urban cleaning vehicles, solenoid valves control water distribution to different utilities: manual lances, rotating brushes, fixed nozzles for sidewalk washing. Electrical management allows the operator to selectively activate necessary utilities through onboard vehicle commands, optimizing water consumption.
In fixed industrial washing systems, where multiple work stations must be fed from a single water central, solenoid valves allow managing individualized delivery. Each station can be equipped with presence sensors that automatically activate the solenoid valve when the operator is in position, turning it off during breaks and thus minimizing waste.
Misting systems and evaporative cooling use solenoid valves to precisely dose nebulized water. Programmed opening and closing cycles allow maintaining desired environmental conditions with optimized water consumption.
The correct installation of a solenoid valve is fundamental to ensure its proper operation and maximum durability. The valve must be positioned so that the flow direction corresponds to that indicated by the arrow stamped on the body (when present).
It is important to verify the presence of a minimum operating pressure specified by the manufacturer, particularly critical for indirect-acting solenoid valves. If the available pressure is lower than the minimum, the valve may not open completely or present malfunctions.
The valve orientation must allow discharge of any condensation and facilitate maintenance operations. In general, installation with the solenoid facing upward is recommended to prevent any leaks or condensation from infiltrating the electromagnetic coil.
Electrical connections must be performed according to current electrical safety regulations. It is essential to respect the voltage and current type (AC or DC) specified on the valve nameplate. Incorrect power supply can irreparably damage the coil.
Solenoid valves powered by alternating current present significantly higher current draw during the opening phase (inrush current) compared to holding current. Power circuits must be sized considering this aspect, particularly when multiple solenoid valves are controlled simultaneously.
Installation of overvoltage protections or electrical disturbance protections is recommended, especially in industrial environments where the electrical grid may present instabilities. Transient suppressors or RC filters can significantly extend the life of electromagnetic coils.
Periodic maintenance of solenoid valves is relatively simple but essential to ensure long-term reliability. Routine maintenance operations mainly include cleaning and visual inspection of connections.
Internal seals represent the components most subject to wear. Visible water leaks from connections or valve body indicate the need to replace seals. The availability of maintenance kits containing all replacement seals greatly facilitates these operations.
The presence of impurities in water represents one of the main causes of malfunction. Solid particles can deposit between the shutter and valve seat, preventing complete closure and causing leaks. Installation of filters upstream of solenoid valves is strongly recommended, particularly when using inadequately treated water.
If a solenoid valve does not open, possible causes include: absence of electrical power, burned coil, movable core blocked by impurities, insufficient pressure differential (for indirect-acting valves). Verification with a multimeter of the coil's electrical continuity allows quickly identifying electrical faults.
If the valve does not close completely, causes may be: impurities between shutter and seat, deteriorated seals, weakened return spring. In these cases, it is generally necessary to disassemble the valve for cleaning or component replacement.
Abnormal noises during operation may indicate pressure problems, diaphragm or movable core vibrations. Verification of operating parameters (pressure, flow rate) and checking mechanical fastenings generally allow identifying and resolving these anomalies.
The integration of solenoid valves in advanced automation systems represents one of the most interesting applications in the professional washing sector. Modern car-wash systems use PLCs or industrial controllers to manage complex sequences involving dozens of solenoid valves operating in coordinated mode.
Control systems can implement sophisticated logic that optimizes consumption based on actual needs. For example, presence sensors can activate solenoid valves only when a vehicle is actually positioned, while programmable timers precisely dose the delivery times of each product.
The use of human-machine interfaces (HMI) allows operators to monitor solenoid valve status, view any alarms, and modify operating parameters without the need to intervene on electrical panels. This centralization of control functions greatly simplifies the management of complex systems.
The most advanced systems integrate remote communication capabilities that allow supervision and control of the system even remotely. Standard industrial protocols such as Modbus, Profibus, or Ethernet/IP enable integration of solenoid valves into extended automation networks.
Predictive diagnostics based on continuous monitoring of operating parameters (absorbed current, response times, number of cycles) allows identifying solenoid valves showing signs of degradation before complete failure occurs. This proactive approach to maintenance reduces unplanned system downtime and optimizes management costs.
The technical specifications of solenoid valves must be carefully evaluated to ensure compatibility with the specific application and compliance with sector regulations.
The following table summarizes the main technical parameters to consider in selection:
| Parameter | Low pressure | High pressure | Notes |
|---|---|---|---|
| Max pressure | 10-15 bar | 100-150 bar | Verify minimum pressure for indirect actuation |
| Actuation type | Indirect | Direct | Direct for high pressures |
| Fluid temperature | -5°C / +90°C | -5°C / +90°C | Verify seal material |
| Available voltages | 12V/24V/220V | 12V/24V/220V | AC or DC according to application |
| Configuration | NC (normally closed) | NC (normally closed) | Safety in case of power loss |
Solenoid valves intended for the European market must comply with Machinery Directive 2006/42/EC and Low Voltage Directive 2014/35/EU. Manufacturers must provide CE declaration of conformity and required technical documentation.
For applications in the food industry or in environments with potentially explosive atmospheres, specific additional certifications may be required. Solenoid valves offered by Emiltec, manufactured by reliable brands such as ACL, guarantee compliance with all applicable regulatory requirements.
In the context of Industry 4.0, solenoid valves evolve from simple on/off binary actuators to intelligent components capable of communicating their status and autonomously diagnosing operational anomalies. This technological evolution is driven by the need to increase efficiency, reduce consumption, and minimize system downtime.
Proportional solenoid valves represent a significant evolution, allowing not only complete opening and closing but also intermediate positions controlled with precision. This fine dosing capability enables optimizations in water and chemical product consumption difficult to obtain with traditional on/off valves.
The integration of flow and pressure sensors directly into solenoid valves allows creating self-diagnostic devices that signal operational anomalies early. This distributed intelligence simplifies the overall control system architecture and improves reliability.
Partnership with specialized suppliers such as Emiltec, which selects quality components from reliable manufacturers and offers qualified technical support, represents a fundamental element for designing and managing modern, efficient, and reliable washing systems. Investment in quality solenoid valves and correct integration into systems translates into superior performance, lower operating costs, and greater durability of the entire high-pressure washing system.
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