Flexible metering pumps cope with tough fluids

Flexible metering pumps cope with tough fluids

Keywords Accuracy, Michael Smith, Pumps

Certain processes require small volumes of liquids to be dosed accurately and repeatedly and such applications are said to be ideal for the AR range of mechanically flexed diaphragm-type metering pumps.

Recently introduced by Michael Smith Engineers, the AR range incorporates six models covering capacities up to 15l/hr at maximum discharge pressures of between five and 12 bar.

These pumps have an adjustable stroke length of between 20 and 100 per cent and a stroke frequency ranging from five to 125 strokes per minute and therefore a theoretical turndown of 125 to 1 is possible.

Wetted materials include PVC heads and joints, EPDM O-rings and seats, glass balls and PTFE-coated diaphragms. This means that the pumps are capable of dosing flocculants, phosphates, silicates, sodium hypochlorite, hydrochloric acid, sulphuric acid, hydrogen peroxide, caustic soda and other aggressive/corrosive fluids used in water and effluent treatment applications.

 Michael Smith Engineers' AR range of metering pumps

The pump motors incorporate an accumulator which stores energy on the back stroke and releases energy on the forward motion. This additional thrust force generated by the motor improves efficiency and allows the use of motors with smaller wattage than previously possible for comparable duties.

In the event of overpressure or closed valve condition, the pumps are automatically switched off and the status of an internal contact is switched so that an alarm can be raised. This feature protects the pumps from mechanical or electrical damage and eliminates the need for relief valve protection.

In addition to continuous dosing operation, the pumps can also dose proportionally to reed switch contact impulses and 0-20mA analogue signals.

AR pumps are IP65 rated so that they can operate outside and in wet or damp locations. The pump heads are designed to be rotated through 90° so that they can be mounted horizontally or vertically to suit the application. Also, the base is sized to enable the pumps to be fixed directly onto a water meter.

Further details available from: Michael Smith Engineers Ltd, UK. Tel: Freefone: 0800 3165432; Fax: +44 (0)1483 723110.