Don-Bur (Bodies & Trailers) Ltd of Stoke on Trent, UK, says it is offering a tyre pressure and inflation system with its trailers, from Pressure Systems International (PSI) of San Antonio, Texas, USA. Don-Bur states that poor tyre pressure often leads to uneven tread wear which reduces the tyres’ lifespan and vehicle safety.  The automatic inflation system maintains a constant set pressure unless the tyre is badly damaged.  The system constantly monitors pressure in the tyres and, using pressure from the auxiliary tanks, allows a pulse of air to pass via the axle, and through into the tyre where a top-up is needed.  As it does this, a smart actuator creates electricity which, in turn, turns on an LED light to indicate to a driver when the system is re-pressurising the tyres.  The frequency of air pulse depends on the shortfall in pressure in the tyre so the lower the tyre pressure, the faster the system will pulse and the faster the LED will flash.

The air pressure is drawn from the trailer air supply, generally the air suspension, which then passes through a pressure protection valve in the control box where the pressure is then regulated. The control box is pre-set to the desired tyre pressure, as advised by the tyre provider and applicable to the load on the trailer. In most cases, air is then distributed to the axle beams, which act as a correctly pressurised conduits, although in some cases the axles are internally tubed if the axle beam is not guaranteed to be airtight by the axle OEM. The air is then provided directly from the wheel ends, through hoses, into the tyre valves. The system can be operational whilst stationary or in transit, as once the pressure drops by 3psi in any of the tyres the system will activate automatically.