Differences between monostable and bistable solenoid valves
Table of contents
- 1. Context and objective of the analysis
- 2. What is a solenoid valve and how does it work?
- 3. Monostable solenoid valves: characteristics and operation
- 4. Bistable solenoid valves: features and operation
- 5. Main differences between monostable and bistable solenoid valves
- 6. How to choose the right solenoid valve for your application
- 7. Reliable solutions from an industrial partner
Context and objective of the analysis
Solenoid valves are essential devices for the automated management of fluids in numerous industrial plants. They precisely regulate the opening and closing of pipes through electrical impulses, ensuring safety, efficiency, and real-time control. Among the types available on the market, monostable and bistable versions represent two distinct functional configurations that meet different operational requirements. Understanding their technical and application differences in detail is essential for making an informed choice geared towards maximum system performance.
What is a solenoid valve and how does it work?
A solenoid valve is an electromechanical component capable of controlling the passage of fluids – whether liquids or gases – through a pipe. Its operation is based on a solenoid, i.e. a coil that generates a magnetic field when an electric current passes through it. This magnetic field moves an internal shutter which, depending on the configuration, opens or closes the flow of fluid.
Solenoid valves can be normally closed (NC) or normally open (NO) and are designed to act quickly in response to a signal. They are used in pneumatic and hydraulic systems, irrigation systems, automatic machinery, and industrial production lines. The type of solenoid valve chosen affects the performance, consumption, and overall safety of the system.
Monostable solenoid valves: characteristics and operation
Monostable solenoid valves are so called because they have only one active position, which is maintained by the power supply. When the electrical signal is interrupted, an internal spring automatically returns the valve to its rest position, which may correspond to the opening or closing of the passage, depending on the model.
This configuration is useful in all cases where predictable and safe behavior must be guaranteed in the event of a power failure. In fact, in the absence of power, the valve always returns to its initial position, reducing the risk of unexpected situations in the system. Monostable solenoid valves are easy to install, require only one coil, and generally have low maintenance costs.
They are widely used in industrial automation systems where a default function is required, such as in container filling, temporary activation of pneumatic cylinders, or dosing systems. Even in environments where reliability must be maximized in critical conditions, the monostable option proves to be the best choice.
Bistable solenoid valves: features and operation
Bistable solenoid valves, on the other hand, are equipped with two solenoids that allow the valve to switch between two stable states. Once a pulse is received from one of the two coils, the valve changes state and maintains its position until a new pulse is received, even in the absence of power. This behavior makes them particularly suitable for systems that require the operating state to be maintained without the need for continuous energy consumption.
From a construction point of view, the presence of two coils makes the structure more complex than the monostable version, but also increases its versatility. Bistable systems are preferred in remote installations, in redundant circuits, in devices that require low energy consumption, or in contexts where it is difficult to guarantee continuity of power supply.
Furthermore, bistable valves are effective in cyclic applications where opening and closing commands are well defined in time, such as in timed irrigation systems, pneumatic material transport circuits, or air treatment processes.
Main differences between monostable and bistable solenoid valves
The main difference lies in how they behave when the power supply is interrupted. Monostable solenoid valves automatically return to their rest position, ensuring a known and safe condition. Bistable valves, on the other hand, maintain their previous state, reducing energy consumption but requiring greater attention in the design of safety systems.
From an energy perspective, monostable solenoid valves consume energy as long as they remain active. In long cycles, this can result in constant power consumption, which affects the efficiency of the system. Bistable valves, on the other hand, only use energy during switching, making them more efficient in systems that remain active for long periods of time.
Maintenance is also an aspect to consider. Thanks to their simpler structure, monostable relays are easier to inspect and less prone to faults related to switching components. Bistable relays, although more complex, offer more stable operation in intermittent working conditions and are less affected by current fluctuations.
Finally, safety is a key criterion. In applications where it is essential that the valve assumes a predefined position in the event of a power failure, monostable valves are preferable. Where, on the other hand, it is necessary to maintain a specific configuration even without power, bistable valves are the most suitable solution.
How to choose the right solenoid valve for your application
The choice between a monostable and bistable solenoid valve depends on several factors, which must be carefully evaluated during the design phase. One of the first criteria concerns the continuity of the available power supply. In environments subject to interruptions or in remote systems, the bistable solution can ensure greater operational stability.
A second factor is the desired behavior in an emergency. If it is essential that the system returns to a safe state in the event of a power failure, the monostable valve is the ideal choice. This applies, for example, to chemical plants or production lines where the flow must be interrupted automatically.
Environmental conditions also influence the choice. In environments with dust, humidity, or chemicals, it is preferable to opt for valves with a simplified structure that are easy to inspect, such as monostable valves. Bistable valves can be used successfully in watertight electrical panels or in integrated applications where the number of interventions is limited but the valve status must remain constant.
Finally, the total cost of the system, including energy, maintenance, and spare parts, may influence the decision. Bistable valves reduce long-term operating costs, while monostable valves are more economical during installation and in situations with a low number of cycles.
Reliable solutions from an industrial partner
Mec Fluid 2 designs and manufactures valves and solenoid valves for all industrial needs, offering a complete range of reliable, durable products designed to integrate efficiently into any system. From pneumatics to hydraulics, from production lines to fluid handling, every solution is developed with attention to build quality and functional safety.
The company provides its customers with a specialized technical service that can assist them in choosing between monostable and bistable configurations, assessing specific conditions of use, critical plant issues, and energy efficiency objectives. Support also extends to the after-sales phase, with original spare parts, detailed technical documentation, and direct assistance.
Every Mec Fluid 2 product is designed to guarantee operational continuity, safety, and durability, meeting the needs of various industrial sectors. The wide range of solutions includes standard and customizable models, suitable for pneumatic, hydraulic, and advanced automation systems.
To learn more about the entire range, visit the section dedicated to valves and solenoid valves manufactured by Mec Fluid 2, where you will find detailed technical information and dedicated consulting services.