Close-coupled centrifugal pumps with closed impeller – HD series

Close-coupled centrifugal pumps with closed impeller – HD series

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Salvatore Robuschi HD 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. They are suitable for pumping clean liquids or liquids containing a small percentage of suspended solids. They can be equipped with 4 types of seals to choose from: single, double tandem, double “back to back” and gland packing packing. A version with food connections is also available in a version with a shrouded motor. All pump sizes are equipped with standard IEC electric motors.

HD series pumps are suitable for pumping aggressive organic and inorganic liquids in the chemical industry, general industry, food industry, solvent recovery plants, power generation plants, metallurgical industry and evaporation plants.

Salvatore Robuschi HD 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. They are suitable for pumping clean liquids or liquids containing a small percentage of suspended solids. They can be equipped with 4 types of seals to choose from: single, double tandem, double “back to back” and gland packing packing. A version with food connections is also available in a version with a shrouded motor. All pump sizes are equipped with standard IEC electric motors.

HD series pumps are suitable for pumping aggressive organic and inorganic liquids in the chemical industry, general industry, food industry, solvent recovery plants, power generation plants, metallurgical industry and evaporation plants.

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
Delivery nozzle: from DN 25 to DN 80
Impeller type: closed
Pump materialss: AISI 316 stainless steel
Mounting flanges: PN16 or DIN11851
Typical applications
Industry Application example
Food industry Pumping unfiltered wine, transfer of brines, sauces, syrups, vinegar.
Textile industry Dosing of liquids with dissolved dye or chemicals in an automatic dissolving system.
General industry Transfer of hot water, water and glycol solutions, pumping dirty water from scrubbers.
Product features

The HD series pumps are monoblock centrifugal pumps for difficult applications. Thanks to their simple design and high modularity of components, they are characterized by a small number of spare parts and low operating costs. Design with a closed impeller (HD) is suitable for pressing clean liquids lub cieczy zawierających a small percentage of solids in suspension.

Pumps with flanged connections comply with EN 22858 (ISO 2858), so they are interchangeable with other pumps that comply with this standard. The HD series pump has four types of seals to choose from: single, double tandem, double back-to-back and gland packing. This means that 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 size of the pump. In addition, all pump sizes are equipped with standard IEC electric motors.

HD series pumps are suitable for pumping aggressive organic and inorganic liquids in the chemical industry, general industry, food industry, solvent recovery plants, power generation plants, the metallurgical industry, and small evaporation plants.

  • Versatility – 7 different sealing arrangements (including various flushing methods), industrial PN16 flange connections or food-grade DIN 11851, meaning 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 and open 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 HD pumps are type B35 (flange and foot version) and are normally available on the market. The shaft is fixed to the motor shaft and can be replaced if worn.
  • Wide range of applications – for general, chemical, food, energy, metallurgical 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 HD centrifugal pump construction. 1. Standard IEC motors
The motors mounted 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. Optimized impeller geometry
Closed impeller, with the possibility of axial adjustment, guarantees maximum hydraulic efficiency of the pump.

Design versions
HDM Monoblock version with standard B35 electric motor and UNI PN 16 flanged connections.
HDA 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 body and the pump drive. Packings are still used in many applications.

Types of connections
Flanged connection for Salvatore Robuschi centrifugal pumps. Flange connection interchangeable with chemical pumps according to ISO 2858.
Food connection for Salvatore Robuschi centrifugal pumps. DIN 11851 food connections or others on request.
  • Technical specifications

  • Typical applications

  • 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
Delivery nozzle: from DN 25 to DN 80
Impeller type: closed
Pump materialss: AISI 316 stainless steel
Mounting flanges: PN16 or DIN11851

Performance curves

Video