ABSTRACT
The drain plug may be replaced by a stop valve which, when connected to the water mains, provides a quick flushing-down at the end of the work shift. It also enables the stator to be fed with water at the beginning of the morning shift to prevent undue stator wear at start-up.The ball bearings require periodic cleaning and it is advisable to establish the correct maintenance schedule by regular examination.Mono Pumps Ltd are located at Arnfieid Works, Audenshaw, Manchester M34 5JA. 3.1.1 Downland grc spray pump unitThe pump (Figure 3.2) is mounted on castor wheels and comprises a mortar hopper with sieve, safety guard and vibrator, feeding the mortar to a Mono Pump MT420. The Mono Pump is driven by an enclosed fan cooled electric motor. To maintain the essential accuracy of slurry output, the pump is driven through a variable speed thyristor control linked to the drive motor. The thyristor control permits manual setting. An electronic speed indicator displays the rotor speed (Figure 3.3).By thyristor speed control, transmission losses are minimized allowing the use of a 1.5 hp single phase 240 V motor. All the controls are grouped on one panel. They include air regulators and pressure gauges for each of the compressed air systems, electric switch gear for auto and hand control, pump speed regulator and speed indicator, and compressed air filter and lubricator. The control panel may also be supplied as a wall mounted unit, or as a separate console when it is necessary to group controls on automated plants.The specification for this unit is given in Table 3.1. The Downland grc spray pump unit is obtainable from K&CMouldings (England) Ltd, Spa House, Shellanger, Diss, Norfolk IP22 2DF. Table 3.1 Specification for the Downland grc spray pump unit. _____________________________________________
3.1.2 Power-Sprays grc spray pumpThe Power-Sprays company has marketed grc spray units for a number of years using initially the narrow
pumps. Figure 3.5 shows a particular unit that enables the stator to be easily removed for cleaning and has the controls housed in the pump cabinet, protected and viewed through a wire mesh screen. Vibrating screens are now offered on top of the hopper feed. Power-Sprays Ltd are based at Orchard Works, Whale Wharf, Littleton-on-Severn, Thornbury, Bristol BS12 1NP.
