Monoblock centrifugal pumps with open impeller – HG series

Monoblock centrifugal pumps with open impeller – HG series

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Salvatore Robuschi HG pumps are monoblock centrifugal pumps for demanding applications. Thanks to their simple design and high modularity of components, they are characterized by low operating costs. Designed for pumping liquids with suspended solids, also viscous, with gas or air (up to 10% content). They have 4 types of seals to choose from: single, double tandem, double “back to back” and gland packing. A version with food connections is also available in a version with a shielded motor. All pump sizes are equipped with standard IEC electric motors.

HG series pumps can handle slightly contaminated liquids or non-abrasive slurries in the chemical and petrochemical, general, food, sugar, water/solvent recovery process, power plants, steel, textile and other industries.

Salvatore Robuschi HG pumps are monoblock centrifugal pumps for demanding applications. Thanks to their simple design and high modularity of components, they are characterized by low operating costs. Designed for pumping liquids with suspended solids, also viscous, with gas or air (up to 10% content). They have 4 types of seals to choose from: single, double tandem, double “back to back” and gland packing. A version with food connections is also available in a version with a shielded motor. All pump sizes are equipped with standard IEC electric motors.

HG series pumps can handle slightly contaminated liquids or non-abrasive slurries in the chemical and petrochemical, general, food, sugar, water/solvent recovery process, power plants, steel, textile and other industries.

Technical specifications
Pump capacity: up to 200 m3/h
Lifting height: up to 60 m
Maximum working pressure: 8 bar
Temperature: up to 120°C
Discharge nozzle: from DN 25 to DN 80
Impeller type: semi-open
Materials: AISI 316 stainless steel
Mounting flanges: PN16 or DIN11851
Typical application
Industry Application example
Food industry Pumping hot alcohol (110°C) with fine particles in vacuum distillation plants, pumping acidic wastewater, recovering demineralized water, pumping grape juice in the wine industry, yeast waste, sugar solutions.
Wastewater treatment Transfer of acidic wastewater in vacuum evaporation plants, brines, pumping liquids in flotation recirculation processes.
Chemical industry Transfer of water and glycol solution.
Chemical industry Pumping caustic soda in the soap and glycerine production industry.
Product features

HG series pumps are monoblock centrifugal pumps for demanding applications. Thanks to their simple design and high modularity of components, they are characterized by unlimited spare parts and low operating costs. The open impeller design (HG) is suitable for pumping liquids with a suspension of solids (non-fibrous), also viscous, with gas or air.

Flanged pumps have the same center-to-center dimensions according to EN 22858 (ISO2858), so they are interchangeable with pumps from other manufacturers that meet this standard. The HG series pump has four types of seals to choose from: single, double tandem, double back-to-back and gland packing packing. As a result, these pumps can be used for difficult applications. A version with food connections is also available in a version with a shielded motor. The maximum working pressure is 8 bar depending on the pump size. In addition, all pump sizes are equipped with standard IEC electric motors.

HG series pumps can handle slightly contaminated liquids or non-abrasive slurries in the chemical and petrochemical industries; they are well-suited for handling liquids with a gas content of up to 10%. They are also used in general industrial services, the food industry, dissolved air flotation systems, the sugar industry, water/solvent recovery processes, power plants, the steel industry, the textile industry, and small evaporation plants.

  • Versatility – 7 different sealing arrangements (including various flushing methods), industrial flange connections (PN16) or food-grade (DIN 11851 as standard) means that these pumps can be used in many different industries for a variety of applications.
  • Only one casing for each pump size – the same casing can be used for both closed (with wear ring) and open (with replaceable wear plate) impellers. Just a few changes are needed to adapt the pump to new plant and process requirements. The pump casings are made using casting technology and are electrochemically polished.
  • Wear plate also in monoblock version – considering that the pump body is the most expensive part in a monoblock centrifugal pump, the possibility of replacing the wear plate allows for a significant reduction in maintenance and servicing costs.
  • Standard IEC electric motor – the standard motors used in HG pumps are of the B35 type (flange and foot version) and are normally available on the market. The shaft is fixed to the motor shaft and can be replaced in case of wear.
  • Wide range of applications – for the chemical, petrochemical, food, sugar, energy, metallurgical, textile industries and small evaporation plants.
Operation principle

Operating principle of centrifugal pumps.The two main parts of a centrifugal pump are the impeller with blades (impeller) and the pump housing (casing). In the most common type – the centrifugal pump with a volute casing – the liquid enters the pump near the center of the high-speed rotating impeller. The liquid on the suction side moves along the axis of the impeller and due to the centrifugal force generated by the blades, it is thrown radially into the chamber in the casing. The casing gradually expands in a spiral manner towards the discharge nozzle, which reduces the velocity of the liquid and thus increases the pressure (diffuser effect). At the same time, as the liquid is thrown radially by the impeller due to centrifugal force, the pressure in the center of the impeller drops, enhancing the effect of drawing liquid into the pump, which enables a continuous liquid transfer process.

The impeller of a centrifugal pump is driven by a motor (most often electric) via a shaft. The pump head, along with the coupling and motor, constitutes the pump unit. In centrifugal pumps, gears are not used, and the rotational speed of the motor is transmitted directly. Most commonly, two- and four-pole motors are used (rotational speeds of approximately 2900 and 1450 rpm, respectively), and less frequently, six- and eight-pole motors are used (approximately 900 and 700 rpm).

A very important element of the pump is the seal at the point where the drive shaft enters the body. This seal is designed to prevent the pumped liquid from leaking out of the pump, maintain pressure inside the pump, and prevent air from entering the pump. Among the seals for centrifugal pumps, we can distinguish gland packing packings, single mechanical seals, and double mechanical seals. We also distinguish a special type of pump – sealless (hermetic) pumps.

Construction

 

Salvatore Robuschi HG centrifugal pump construction. 1. Standard IEC motors
The motors fitted on Salvatore Robuschi HD pumps are of the B35 type (with flange and feet), which are readily available on the market. The pump shaft is fixed to the motor shaft and is replaceable in case of wear.2. Different Sealing Systems
4 types of sealing arrangement to choose from: single, double tandem, double back-to-back and gland packing packing.3. One casing, two impellers
Each pump size can utilize a unique casing that applies to both closed and open impellers (with a replaceable wear plate). This versatility allows for easy pump application in new installations and processes.4. Replaceable Wear Plate
Considering that the pump body is the most expensive part in a monoblock centrifugal pump, the ability to replace the wear plate significantly reduces maintenance and repair costs.
Design versions
HGM Monoblock version with standard B35 electric motor and UNI PN 16 flanged connections.
HGA Monoblock version with standard B35 electric motor and DIN 11851 food connections.
Types of seals
Single mechanical seal in Salvatore Robuschi centrifugal pumps. Single mechanical seal

The most popular mechanical seals for use with non-contaminated liquids (no solids). The pumped liquid lubricates the sealing surface and dissipates heat.

Double mechanical seal in Salvatore Robuschi centrifugal pumps. Double back-to-back seal

A back-to-back double seal is a solution with a pressurized chamber. The external barrier fluid, supplied at a pressure approximately 0.5 – 1 bar higher than the pressure of the pumped medium, separates the product from the atmosphere.

Double tandem mechanical seal in Salvatore Robuschi centrifugal pumps. Double tandem mechanical seal

This type of seal has two pairs of face seals facing in the same direction. The use of this seal allows for a gradual reduction of pressure from the pump chamber or the use of a flushing medium and monitoring of the main mechanical seal of the product. The external service liquid reservoir serves to separate the pumped product from the atmosphere.

Packing seal in Salvatore Robuschi centrifugal pumps. packing seal

Packing seal is a special cord wound around the shaft separating the space between the pump body and the drive. It does not provide 100% tightness due to the need for continuous lubrication and cooling of the cords.

Types of connections
Flanged connection for Salvatore Robuschi centrifugal pumps. Flange connection interchangeable with chemical pumps.
Food connection for Salvatore Robuschi centrifugal pumps. DIN 11851 food connections or others on request.
  • Technical specifications

  • Typical application

  • Product features

  • Operation principle

  • Construction

  • Design versions

  • Types of seals

  • Types of connections

Pump capacity: up to 200 m3/h
Lifting height: up to 60 m
Maximum working pressure: 8 bar
Temperature: up to 120°C
Discharge nozzle: from DN 25 to DN 80
Impeller type: semi-open
Materials: AISI 316 stainless steel
Mounting flanges: PN16 or DIN11851

Performance curves

Video