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EQUIPMENT

Centrifugal Horizontal Pumps - 29122 HORIZONTAL CENTRIFUGAL PUMPS

in

GRAPHILOR

® (impervious graphite)

SERIES NH

Pumps to standards NF E 44121/DIN 24256/ISO 2858

Construction

MECHANICAL SEAL The NH series standard horizontal axis centrifugalpumps are of the “process” design type.They comprise 2 assemblies :• the first including the body (A) and its frontflange (G) and rear flange (H).• the second including the bearing-frame (V) fittedwith the impeller (B) and the rear flange plate (C).This design, and the fact that the coupling is fittedwith a spacer part, allow easy dismantling of the second assembly to access the impeller (the first assembly remaining fixed to the baseplate and to the suction and discharge pipes). Under these conditions, it is no longer necessary to dismount and realign the motor.The discharge orifice is located on the pump axis,making pipework connection and design particu- larly easy. Pumps are fitted with open or closed impellers depending on the required flow rate characteristics and discharge head. For open impellers, the correct clearance at the front (between impeller vanes and body) is obtained by adding or removing spacer washers.The shaft is sealed by installing standard CARBONE LORRAINE “single” or “double” type seals (see diagram below). Other types of seals can also be supplied (see section “Options”).The bearing-frame is reinforced. It contains twobearings : roller on the pump side, and double row of oblique contact balls on the motor side.Bearing lubrication by grease allows up to1500hours of operation without the addition of grease (except in the largest model which is oil lubricated).The shaft has a slight offset which eliminates ben-ding and vibration, thus enlarging the lifetime of the seal and the roller bearings.The shaft end is standardised to NF E 44121/DIN 24256/ISO 2858. Design