Hot Water Circulation Pumps Type NHL / HPL / HPR / NHM

General DICKOW hot water circulation pumps, type NHL, HPL, HPR and NHM, have been developed for medium and large size heating plants, for heating calanders, presses, large buildings and similar applications which require temperatures >180 °C (356 °F). The design of the pumps is based on long years of experience in the field of handling hot water and grants high availability and reliability in operation. The NHL series is designed for pressures up to 45 bar @ 238 °C (464 °F), maximum capacity is appr. 900 m3/h (3960 gpm) and differential head appr. 150 mLC (492 ft). The HPL / HPR series is designed...

Shaft, shaft sleeve The pump shaft is able to transmit the full driver output and is accurately machined throughout his entire length and is properly finished at the bearing surfaces. In order to have satisfactory seal performance the shaft diameter and overhung are sized to minimize shaft deflection at the seal faces. The shaft design guarantees a critical speed of more than 10% over the maximum operating speed. The connections ”cap screw - hub” and ”hub - shaft sleeve” are sealed by confined gaskets and the pump shaft has no contact to the pump fluid. The pump shaft is carried by generously...

heavy duty antifriction bearings volute casing centerline mounted bearing bracket, oil lubricated replaceable wear ring closed impeller drain plug confined gasket seal chamber

Shaft sealing Due to high vapour pressures of hot water, standard mechanical seals can not be used for high temperatures. Mechanical seal "Re" with water cooled stationary seat and cooling jacket - NHL water cooling The "Re" design requires cooling water for the stationary seat and the cooling chamber. mech. seal stationary seat There is no circulation available (dead end). A throttle separates the hot pumped liquid from the cooled liquid in the seal chamber. Cooling water consumption 300-700 l/h. Allowable operating temperature: NHL s max. 205 °C (401 °F) NHL huh max. 238 °C (464 °F) cooling...

Mechanical seal "Ref" with circulation through water cooled heat exchanger (API-plan 23) – NHL / HPL Circulation leads from a pumping ring over the seal, through a water cooled heat exchanger and back to the seal chamber. The cooling water goes through a cooling jacket in the intermediate casing and through the heat exchanger. intermediate casing water cooling inlet Cooling water consumption: 300-700 l/h. heat exchanger water cooling outlet cooling jacket Allowable operating temperature: HPL / HPR max. 280 °C (536 °F) NHL huh max. 238 °C (464 °F) pumping ring Pump with magnetic coupling - NHM...

Performance range Performance curves for the different pump sizes are available on request, also for 1750 / 3500 rpm. Technical changes reserved. Printed in the Federal Republic of Germany. 100-06.16 S&W