what is tractor protection valve

Tractor protection valve (TPV) is an essential safety device present in all commercial vehicles with air brakes. It is designed to ensure that a failure in the trailer brake system does not cause the tractor's brake system to lose air pressure and become inoperative. In this article, we will discuss the importance of TPV, how it works, and its maintenance requirements.

Why is TPV important?

The TPV is an important safety feature that prevents dangerous accidents by ensuring the tractor brakes remain operational even if the trailer brakes fail. In the absence of a TPV, loss of pressure in the trailer brake system could drag the tractor's air supply too low, causing it to fail. This would result in a ‘deadly combination' where brakes will not work properly, and the vehicle will be out of control. Hence, TPV plays a crucial role in ensuring the safety of the driver, passengers, and other road users.

How does a TPV work?

The TPV is installed in the tractor's air brake system and located near the rear of the cab, behind the driver's seat. It contains a piston that separates the tractor's brake system from the trailer system. When the brakes are in use, air pressure builds up in the brake pipe, causing the piston's diaphragm to compress. This opens the valve and allows the compressed air to enter the tractor's brake system and activate the brakes.However, if the brake pipe pressure drops below a specific level, such as in the case of a ruptured air hose or a disconnected trailer, the TPV will activate. This occurs when the diaphragm in the TPV moves from its original position, thus cutting off the air supply from the trailer brake system to the tractor brake system, protecting it from losing air pressure and disabling the brakes.

Maintenance of TPV

Like any other mechanical device, TPV requires proper maintenance to ensure it works correctly. Regular maintenance is crucial to keeping a vehicle's air brake system operating at its best, reducing the risk of accidents on the road. The TPV should be examined visually for any cracks, damage to fittings, air leaks, or if it's not functioning correctly.Moreover, the TPV should be subjected to an annual inspection by maintenance personnel qualified for air brake systems. These inspections should be carried out with calibrated testing equipment to ensure that the TPV's pressure levels are calibrated precisely, guaranteeing the safety of the driver and those sharing the road with them.

Conclusion

Tractor protection valve is a crucial safety device that helps prevent fatal accidents by ensuring the brakes stay functional even if there is a failure in the trailer brake system. All commercial vehicles with air brakes must have a properly maintained and functioning TPV installed to ensure the safety of drivers and other road users. Thus, regular inspection and maintenance of TPV should be a part of every vehicle's preventative maintenance.