NDD Series Between Bearings Single / Two Stage Double Flow Axially Split Volute Casing Pumps

Product Overview

Description

Design: series pump units consist of acentrifugal pump and an induction motor in the explosion-proof version,which are mounted either on a common base plate (if the nominal powerof the motor is less than 400 kW) or on separate base plates. The pumpand motor shafts are connected by means of a flexible coupling. Thepump units shall be rigidly anchored to the foundation, and pipingshall be also rigidly connected to the pumps. The pumps as componentsof the pump units are electrically driven horizontal, between-bearings,single- or two-stage centrifugal pumps with double entry impellers.

The pump casings are:

1. axially split, with a semi-spiral inlet hydraulic passageand a spiral outlet hydraulic passage (in case of 140-140, 420-100, 420-200, 800-30, 800-60, 1100-60 and 1200-70);
2. radially split, with a tangential semi-spiralinlet hydraulic passage and a circular outlet hydraulic passage (incase of 600-320 2, 500-290 2, 800-230 2 and 850-1802).

Flanged nozzles are integrally cast with the pump casing and are oriented:

1. horizontally (discharge) and vertically to the bottom (suction) in the 140-140 model pumps;
2. tangentially(the suction nozzle is on one side and discharge nozzles is on theother side of the shaft centerline), facing opposite directions, in the 420-100, 420-200, 800-30, 800-60, 1100-60 1200-70 pump models;
3. radially at side (suction) andvertically to top (discharge) in the 600-320 2, 500-290 2, 800-230 2 and 850-180 2 pump makes.

Counter flanges have a weld neck.

The rotor axial thrust is hydraulically balanced. The residualaxial forces arising as a result of an uneven wear of sealing surfacesin the running clearances are taken up by the bearings.

Casings of the pumps for hot refined products are supported in thehorizontal plane near the shaft centerline to accommodate thermalexpansions. In order to allow for free expansion of static componentswhilst maintaining coupling alignment, the pump feet on the drive sideare rigidly dowelled to the base plate pedestal and the other end ispinned so that it should be axially moveable.

The rotor in the 140-140, 420-100, 420-200, 800-30, 800-60, 1100-60 and 1200-70 pump models is carried by theoil-bath lubricated antifriction bearings with forced cooling.

The rotor in the 600-320 2, 500-290 2, 800-230 2 and 850-180 2 pump makes is carried by the pressure lubricated plainbearings, with lube oil supplied by a pressure lubrication installation.

Shaft sealing is by mechanical seals:

• in tandem arrangement, which utilizes a pressurized barrierfluid, neutral to handled medium, and is provided with a cooling systemin case of the pumps for hot refined products;
• single seals provided with a liquid cooling system in case of the pumps for industrial water.

Upon the Customers request, pumps intended for handling industrial may be furnished with packed glands.

Handled medium near the shaft seals is cooled by cooling liquid supplied into the thermal barrier chambers.

Sense of rotation of pump shaft is shown with a rotation arrowattached to the pump casing or to the bearing housing on the driveside.

DN	mm	100 - 350	200-350
Q	m3/h	up to 1440	up to 1020
H	m	up to 238	up to 325
p	kg/cm2	4	10
t	o	+80	+400
n (sync)	rpm	1000, 1500	3000