HDG segmented multistage centrifugal pumps are a series of products carefully developed by our company after introducing digestion and absorption of foreign high-efficiency hydraulic models.This product is mainly used for boiler water supply in thermal power plants and steel mills to remove iron oxide from the surface of steel plates during the hot rolling process. It is characterized by high efficiency and energy saving, reliable operation and easy maintenance.

    Flow: 12~750m³/h
    Head: 140~3070m
    Deliver medium temp:20~180ºC

    Example:
    HDG B 600 / 9 S
    HDG: sectional multistage pump
    B: forging (No marking for casting)
    600: Rated flow
    9: Stage qty
    S: Double suction (No marking for single suction)

    HDG type pump is a segmented multi-stage horizontal centrifugal pump, which is mainly composed of the pump body (suction section, middle section, discharge section), rotor components, guide vane, shaft seal system, bearing components and balancing mechanism.The suction port and discharge outlet of the pump are all vertically upward.The pump body is mounted on the base by centerline support.

    1. Pump body: A high-stiffness threaded bar is used to connect the suction section, the discharge section, and the middle section into one.The seal between the pump bodies adopts a square-shaped sealing ring + a hard seal on the metal surface, and a metal winding pad is used for sealing at special temperatures.
   
    2.Rotor assembly: The pump rotor is composed of parts such as the pump shaft, impeller, balance drum (disc), balance sleeve, thrust disc and coupling, and is a rigid rotor.The entire rotor needs to be dynamically balanced at high speed with an accuracy of G2.5, which effectively ensures the stability of the pump operation.The pump shaft is forged from high-strength alloy steel and the surface is chrome-plated, which effectively improves the surface hardness and enhances the protection of the pump shaft.The cooperation between the impeller and the shaft adopts two methods: single-stage positioning sliding installation or interference hot installation.The balance plate or balance drum adopts a separate positioning method.

    3.Shaft seal system: There are two forms of shaft seals, container-type mechanical seals and packing seals.The mechanical seal flushing scheme generally adopts PLAN23. This scheme does not require external condensate for flushing. The external cooler and cooling chamber can effectively keep the internal circulation of the seal at a relatively low temperature, effectively extending the service life of the mechanical seal friction pair, and the continuous operation time can reach more than 8,000 hours, ensuring that there is no leakage on site.When replacing mechanical sealing accessories, only the dynamic and static rings and O-rings need to be replaced, and the cost is lower.There is no need to adjust the compression amount of the seal.For lower temperature media, the sealed flushing scheme can choose other flushing schemes such as Plan21 self-flushing or Plan32 external flushing.

    4.Bearing assembly: Radial bearings use sliding bearings, and cylindrical four-oil wedge sliding bearings are formed by machining to eliminate manual scraping; thrust bearings use tile thrust bearings or rolling thrust bearings.The lubrication method adopts the self-lubricating oil rejection ring of the oil tank or the forced lubrication of the external pressure oil.Effectively extend the service life of the bearing.

    5.Balance assembly: It consists of a balance plate, a balance sleeve, a balance sleeve pressure plate and other components. The mechanism balances the axial force of the rotor through changes in the liquid pressure and leakage in the front and rear cavities of the balance plate, and the liquid behind the balance plate flows into the inlet of the pump through the balance pipe.The residual axial force is borne by tile thrust bearings or thrust ball bearings.

    6.Guide assembly: The bottom of the pump body is provided with a guide device to ensure that the pump always expands freely along the centerline of the shaft after being heated. On the one hand, the bite between the rotor and the stator is prevented, and on the other hand, the inlet and outlet pipes of the pump are always displaced in the direction that the pipe bracket can compensate, effectively reducing stress concentration, thereby improving the stability of pump operation.

    7.Pump base: The base of the pump is welded with high-strength steel, and there are two types of split base and joint base.There is an adjustment device on the base to facilitate the overall installation of the unit.

    1.The parts are highly interchangeable.

    2.The maintenance of the pump and the replacement of some wearing parts are extremely convenient.Bearings, seals and balancing devices can be replaced without disassembling the inlet and outlet pipelines.

    3.The best matching of impeller and guide vane, reasonable fit gap and wide axial throttling design are important factors for the long-term stable and efficient operation of the pump.

    4.Good cavitation resistance.Using an excellent impeller hydraulic model or a special double-suction impeller structure, the user does not need to configure the front pump or increase the height of the inlet tank.

    5.Safe pump body sealing design.According to different pressures and structures, the pump body adopts a hard seal facing the metal surface and a metal winding pad or O-ring seal.

    6.According to user requirements, the intermediate tap can be added.
 

    The HDG type segmented multistage centrifugal pump is equipped with a monitoring instrument to monitor the unit during operation and prevent the occurrence of unit accidents.

    Radial support bearings, axial thrust bearings and housings are equipped with temperature monitoring instruments, which transmit DCS signals in situ and remotely.;

    Pressure indicator instruments are equipped at the suction port, discharge outlet, balance water pipe, lubricating oil inlet pipe, etc.;

    The suction port filter is equipped with a differential pressure indicator;

    The bearing bodies at both ends are equipped with integrated vibration monitoring devices, which transmit DCS signals on-site and remotely.;

    Monitoring of speed and reversal protection, on-site and remote transmission of DCS signals;

    HDG type high-pressure multistage centrifugal pump, during use, the pump outlet pipeline must be equipped with a recirculation system, so that under special circumstances, the pump body overheats and internal vaporization causes equipment damage and on-site accidents.At present, the valve of the recirculation system adopts an integrated mechanical bypass air discharge check valve and a split electric minimum flow regulating valve, which can protect the pump according to changes in the outlet flow of the pump.