Valves Overview

Valves are fundamental mechanical components that come in various shapes and sizes, used across a wide range of equipment, machinery, and processes. They can be fully opened or closed, or positioned in between, to control the availability, flow, and pressure of gases and liquids. This blog focuses on solenoid-operated valves—commonly referred to as solenoid valves—and their role in enabling numerous industrial automation functions.

Automotive Lift Repair Tampa Florida Solenoid Actuation Method

An actuator is any device that physically moves a valve. Manual valves require a person to operate a handle, while automatic valves utilize electro-mechanical systems, allowing them to be controlled remotely by operators or control systems, expanding their functional capabilities.

One method of Automotive Lift Repair Tampa Florida actuation involves electro-mechanical solenoids that directly or indirectly operate valves. A basic solenoid comprises an electrical coil wound around a movable metal core or piston, which may be spring-loaded. When a control voltage—typically 12Vdc, 24Vdc, 24Vac, or 120Vac in industrial settings—is applied, the coil acts as an electromagnet, moving the core.

 Process Valves

For smaller process valves, typically up to 2 inches in diameter, a solenoid can generate enough force to operate the valve directly. These compact solenoid process valves are ideal for controlling the on/off flow of pressurized gases or liquids in machinery.

For instance, consider a machine that conveys parts for washing. Solenoid process valves could control the application of compressed air to a cylinder that extends to hold the part, as well as supply water to a nozzle for washing.

 Automotive Lift Repair Tampa Florida Control Valves

For larger valves, pneumatic control is a common actuation method. Small solenoid control valves can apply compressed air (or another gas) to operate a pneumatic mechanism, which in turn opens and closes larger valves. These mechanisms can be either rotary or linear actuators, with small solenoid control valves often referred to as pilot valves.

Control valves can be standalone components or part of modular assemblies, which allow for multiple solenoids to be grouped on a single manifold. Solenoid manifolds are more compact than individual valves, simplifying plumbing and installation. Each solenoid may be hard-wired, but newer intelligent manifolds can use industrial communication protocols, enabling programmable logic controllers to operate multiple solenoids via a single network connection.

 Solenoid Valve Sizing

When selecting solenoid valves for specific applications, designers should consider several factors:

– Service Type: Automotive Lift Repair Tampa Florida Process valves control media (like air, oil, or water) in piping, while control valves typically operate other valves and equipment pneumatically using compressed gas, usually air.

– Sizing Requirements: Valves should be sized to handle expected operating conditions and pressures, providing adequate flow for the application. Each valve has an allowable pressure range and a flow coefficient (Cv) value that indicates flow characteristics. Many suppliers provide calculation tools for sizing assistance.

– Port Size: Connection ports must match the sizes of piping and fittings, and flow sizing will impact the available port sizes.

– Valve Types: Basic valves can be 2-way, 2-position (two ports, two positions) or 3-way, 2-position (three ports with one common port connected to one of the other two at a time). Control valves can also be configured similarly, with variations such as 5-way, 3-position arrangements.

– Options: Some Automotive Lift Repair Tampa Florida solenoids are hardwired, while others may accommodate connectorized cordsets for easier installation. Optional features like LED indicator lights and surge suppression enhance troubleshooting and extend operational life.

 What is a Solenoid Control Valve?

A solenoid control valve allows engineers to autonomously and remotely manage fluid flow within a system, eliminating the need for manual valve operation. This flowing media can include water, air, gas, oil, steam, or refrigerant.

The solenoid control valve consists of two primary components: the solenoid at the top and the valve mechanism at the bottom. Electromagnetism generated by electrical currents moves the plunger up or down, regulating flow. 

 How Does a Solenoid Valve Work?

A solenoid valve features two main parts: the solenoid and the valve body. The solenoid includes an inductive coil surrounding an iron core (the plunger).

In a “normally open” solenoid valve, the valve is closed when not energized. When a current flows, the magnetic field activates, moving the plunger to open the valve. Conversely, in a “normally closed” valve, an energized current lifts the plunger, allowing the media to flow through.

 Types of Solenoid Valves

Due to their versatility, solenoid valves come in various designs, each serving different functions. Here are five common types:

1. Automotive Lift Repair Tampa Florida Direct-Acting Valves  

   These simple solenoid valves are used for applications with smaller flow rates and do not rely on external pressure. The valve opens directly when the electromagnetic coil pulls the plunger, allowing media to pass through. They do not have a minimum operating pressure, and flow rate depends on the orifice diameter and magnetic force.

2. Pilot-Operated Valves  

   Also known as servo-operated valves, these indirect-acting valves require a pressure differential to operate (minimum 0.5 bar). They consume less electrical energy, function at a slower rate, and need full power to stay open. A rubber membrane with a small hole controls the flow, and the pressure difference facilitates the operation of smaller solenoids for high flow rates.

3. Two-Way Valves  

   The most common solenoid control valve, two-way valves have two ports: a cavity port and a body orifice port. They can be either “normally open” or “normally closed,” with normally closed valves remaining shut until energized.

4. Three-Way Valves  

   These valves feature three ports and are ideal for operations requiring alternate pressure. They can be configured for mixing (two inlets, one outlet) or diverting (one inlet, two outlets), allowing media to flow in specific directions based on whether power is applied.

5. Automotive Lift Repair Tampa Florida Four-Way Valves  

   Commonly used with dual-acting cylinders or actuators, four-way valves have four or more port connections. Two ports provide pressure while the other two manage exhaust. Their settings can be normally open, normally closed, or universal.

 Applications of Solenoid Valves

Solenoid valves are versatile and can handle a range of pressures and flow rates.