General requirements of suction machine for cleaning sewers, manholes and ancillary structures provided on sewer line and closed stormwater drains
1992 Edition

The recommended vacuum pump type is a rotary vane pump, as specified in the standard. This pump is characterized by a straightforward design that facilitates maintenance and is capable of generating sufficient vacuum to extract slurry containing grit and solids from depths between 8 to 12 meters using a deep suction apparatus. This ensures dependable performance in sewer and manhole cleaning by efficiently handling abrasive materials.

The suction pipe must have a minimum diameter of 100 mm and be equipped with a quick-acting valve designed to prevent leakage of tank contents during loading. Above the top end of the suction pipe, a replaceable wear plate should be installed to minimize wear. The hoses connected must withstand up to 90% vacuum, be resistant to corrosion and abrasion, and incorporate quick coupling devices for ease of connection. The valves should also permit passage of sewage containing grit and floating fibers up to 50 mm in diameter.

The tank is constructed using steel and designed with a safety factor of four times the operating pressure to ensure robustness. The rear two-thirds of the tank's volume is designated for solids, separated by a sludge screen into one-third and two-thirds compartments to segregate solids from water, which drains back through a manhole. The sludge screen's bottom tilts during discharge, and the rear door, equipped with reliable clamping, can be operated manually or hydraulically. Interior surfaces are sand blasted and coated with epoxy or bituminous paint for corrosion resistance. The tank is also fitted with safety accessories such as full bore quick-acting valves, pressure relief valves, vacuum relief valves, compound pressure/vacuum gauges, sludge traps, float cut-out valves, lubrication systems, and rotary control valves to ensure operational safety and maintenance ease.

To ensure safe operation, the suction machine should be equipped with pressure and vacuum gauges for monitoring, safety valves to prevent overpressure, quick coupling hoses for secure and leak-proof connections, non-return valves to avoid backflow, filters or strainers to protect the pump from debris, emergency stop switches for immediate shutdown, protective guards to prevent operator contact with moving components, and control valves to regulate flow. These accessories collectively safeguard the equipment and operators while maintaining efficient cleaning functions.

The standard specifies that the tipping gear must be located at the front of the tank and powered hydraulically by the vehicle's drive. It includes control valves for tipping, holding, and lowering the tank, with operating levers situated inside the driver's cab for convenience. The tank is designed so that the rear portion carries solids separated by a sludge screen, which tilts during discharge to facilitate emptying. A rear door, operable manually or hydraulically, allows tipping or transportation. The loading arm is counterbalanced and capable of 270° rotation, operable either manually or hydraulically. Additional accessories such as quick-acting valves, pressure relief valves, vacuum relief valves, and rotary control valves manage pressurization during discharge, while float cut-out valves and level gauges support operational safety and monitoring.