What are the types of trailer control valves?

There are several types of trailer control valves used in air brake systems of commercial vehicles. Here are some of the most common types:

Relay Valve: A relay valve is a pneumatic valve that is used to control the air pressure to the trailer brakes. It receives air pressure from the truck's brake system and applies it to the trailer brakes when the truck driver applies the brake pedal.

Quick Release Valve: A quick release valve is used to release the air pressure from the trailer brakes quickly, allowing them to release faster and reducing the stopping distance of the vehicle.

Spring Brake Valve: A spring brake valve is used to control the spring brakes on the trailer. It is typically used as a parking brake, as it applies the brakes when the air pressure is released.

Service Brake Valve: A service brake valve is used to control the service brakes on the trailer. It is operated by the driver pressing the brake pedal.

Emergency Brake Valve: An emergency brake valve is used to activate the trailer's emergency brake system in case of an emergency. It applies the trailer brakes with maximum force when activated.

Load Sensing Valve: A load sensing valve is used to control the amount of air pressure applied to the trailer brakes based on the weight of the load being carried. This helps ensure that the trailer brakes are always applied with the appropriate amount of force.