Nederman RBU 1300 Instruction Manual

Also see for RBU 1300: User manual

Nederman RBU 1300 Instruction Manual Manual pdf 13 page image

RBU13EN4.2 FunctionThe RBU (Roots Blower Unit) is a series of vacuum units fitted with a 3-lobe roots pumpvacuum source. See ‘Table 4-1: Technical data’ regarding airflow information. The motor isa 3-phase asynchronous motor. See the RBU unit machine tag for details regarding voltage,current, motor power, and frequency.The root pump’s power consumption increases with increasing vacuum and decreasing air flow(pump characteristics).It is necessary to minimise the power requirement during Y/D-starting. This is done by openinga solenoid valve for free admittance of air to the pump when the motor runs in Y-mode.All RBU units are fitted with a combined start up and vacuum limiting valve. This valve iscontrolled by a low friction compressed air cylinder, a solenoid valve and two regulators. Thevalve opens if the vacuum reaches the working vacuum level or the safety vacuum level. Whenthe valve opens incoming air lowers the vacuum. The opening of the valve will depend on (1) thevacuum in pump and (2) the force of the low friction compressed air cylinder pulling the valvein opposite direction. The force in the compressed air cylinder rises when air pressure fed to thecompressed air cylinders raises. In this way, the regulators adjust the vacuum by affecting thevalve disc position which in turn changes the air pressure to the compressed air cylinder.The working vacuum level is adjusted using the regulator closest to the cylinder, see Figure 1item 15. The level is set before delivery and no further adjustment is normally required. SeeSection ‘9.11 Vacuum level’ regarding regulator adjustment.CAUTION! Risk of equipment damage.The safety valve regulator must never be adjusted, Figure 1 item 16. Incorrect setting of thesafety valve regulator damages the pump and the guarantee will be rendered invalid.At the universal valve entrance is a rubber disc back flush valve. The valve is used when twoor more RBU units are hooked up in parallel and prevents units not yet started from runningbackwards.A rubber disc overpressure valve is placed on the universal valve side, see Figure 1 item 18. Theoverpressure valve opens and lets air out if the pump runs in the wrong direction during theinitial start up.After the universal valve, the air passes through the inlet silencer to the roots pump. Underneaththe pump is a rigid discharge silencer. An additional spiro bend silencer leads the air out from theunit.A thermal fuse is placed in the lower flange of the pump, see Figure 1 item 10. This fuse trips at≈ 140 °C (≈ 284 °F) stopping the unit. The start and control unit will then indicate an error. SeeSection ‘9.7 Thermal fuse’ for more information.An optional compressed air switch can be mounted in the vacuum unit to prevent it from startingwith no compressed air supply.5 Main componentsFigure 1 shows the main components of the RBU unit. These are as follows:1. Inlet silencer.2. Outlet spiro silencer.3. Noise-absorbing enclosure.4. Spiro silencer with a 90° bend.