Three Kubota mini excavators working on demolishing internal structures and floors of a multi-storey building in Leeds city centre have been fitted with a specialised exhaust gas purification system.

Hull-based Kubota construction equipment dealer and plant hirer, Venco Plant Services Ltd, hired out the modified Kubota KX41-3 mini excavators to demolition contractor, Controlled Group Ltd of Ossett, for a six month contract.

The main contractor, the Wates Group, specified that plant working within the building had to have an exhaust gas purification system fitted to conform to Health & Safety regulations regarding exhaust emissions in an enclosed space.

Venco Plant Services was asked by Controlled Group Ltd, a regular customer, to ensure that an appropriate exhaust gas filtration system was fitted to the 1.6 tonne machines, which were also supplied with Kubota hydraulic breakers and Abiljo mechanical grapples.


Due to their size, 475mm long x 375mm high, they were mounted in a cradle on the roof of the excavator and then connected to the engine by means of an external heat protected flexible exhaust pipe.

It was vital to protect the engine's efficiency and mechanical integrity from the effects of exhaust gas back pressure. The maximum permissible back pressure for the Kubota engine is 70mmHG (93.32 millibar), so the EHC filters were fitted with back pressure relief valves that operate at 90 millibar and also give an audible warning to the machine operator once the back pressure limit has been reached. The filter element is then changed.

Venco will be adding a pressure gauge to the instrument panel in the cab of each machine to give the operator a visual means of monitoring the exhaust back pressure.

Danny Spaven, Venco Plant Services' Managing Director - Hire Division, said: "With help from Kubota's engine department we located and fitted a very effective engine exhaust gas filtration system that the customer and their client both agree is a huge success."

(CL/SP)