Centrifugal pumps with vortex impeller – RC series

Centrifugal pumps with vortex impeller – RC series

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Salvatore Robuschi RC centrifugal pumps are single-stage vortex pumps designed toreduce spare parts and warehousing costs. All pumps in this series have a single seal housing for all types of seals (single, tandem, cartridge, “back to back” or packed, according to API 682) and bearings designed according to ISO 5199.

They provide gentle pumping of media with viscosity up to 1000 cPs with solids content, including long and filamentous ones – including mixtures of up to 50% air or gas and liquids such as: chemical and crystalline suspensions, viscous and dense liquids with a high concentration of fibrous suspensions, municipal and industrial wastewater, sludge in the textile industry, refineries, general industrial services, pulp and paper industry, food, sugar, power plants and steel industry.

Salvatore Robuschi RC centrifugal pumps are single-stage vortex pumps designed toreduce spare parts and warehousing costs. All pumps in this series have a single seal housing for all types of seals (single, tandem, cartridge, “back to back” or packed, according to API 682) and bearings designed according to ISO 5199.

They provide gentle pumping of media with viscosity up to 1000 cPs with solids content, including long and filamentous ones – including mixtures of up to 50% air or gas and liquids such as: chemical and crystalline suspensions, viscous and dense liquids with a high concentration of fibrous suspensions, municipal and industrial wastewater, sludge in the textile industry, refineries, general industrial services, pulp and paper industry, food, sugar, power plants and steel industry.

Technical specifications
Pump capacity: up to 800 m3/h
Lifting height: up to 60 m
Maximum working pressure: 10 bar
Temperature: up to 180 °C – depending on the pumped medium
Viscosity: up to 1000 cPs
Discharge nozzle: from DN 32 to DN 250
Impeller type: Vortex with free passage up to 180 mm
Materials: Grey Cast Iron GJL250 or AISI 316
Optionally: AISI 304, AISI 904, Duplex, Superduplex, Hastelloy B or C)
Typical applications
Industry Application example
Food industry Transfer of liquids with solids such as fruits, vegetables, sediments, stones, grass, etc.
Water treatment Pumping liquids with suspensions and fibers, such as biological sludge, flocculent sludge, clarification waste.
Chemical industry For crystallizers, transfer, washing and recovery of solids or high viscosity substances.
Textile and tanning industry For chemical baths with suspensions and filamentous liquids.
Product features

RC pumps are single-stage pumps with a special recessed impeller located in the rear of the housing. Thanks to this design, most of the liquid passes through the pump body without direct contact with the impeller. This ensures that all crystals, delicate solids (e.g. peas, corn, beans, olives, seeds, granules), suspensions (e.g. mud, sand), etc. can be transported without any damage. Long and stringy solids pass through the pump without causing blockages. The Vortex impeller is capable of pumping mixtures of up to 50% air or gas. In addition, this series of pumps can be used for pumping media with viscosity up to 1000 cPs.

RC series centrifugal pumps are designed with a modular construction to reduce spare parts and storage costs. Many devices use common spare parts. In addition, all Salvatore Robuschi vortex series have one seal housing for all seal types. When replacing a few elements, the pumps can be equipped with single, tandem, cartridge, back to back or packing seals. Seals can be equipped with a PLAN according to API 682 (e.g. PLAN 11, PLAN 52, PLAN 53, PLAN 54).

  • Modularity – 4 groups of bearing housings and shafts covering 18 different pump sizes. Oversized bases provide high stability, and the flanged design avoids problems associated with pump and motor misalignment.
  • Unified bearing housing – the same bearing housing can be used for pumps with closed, open, channel and vortex impellers. Design compliant with EN 25199, ensuring shaft deflection < 0.05 mm and min. 18,000 hours of operation, also designed to balance axial and radial loads and reduce operating temperature.
  • Higher abrasion resistance – the pump body has been designed to pump liquids along with suspensions, even if they are abrasive. The continuity of the surface prevents any blockages from occurring. All points exposed to wear have been appropriately shaped.
  • Vortex impeller with large free passage – free passage up to 90% of the nozzle diameter. The special recessed impeller ensures the flow of solids and fibrous materials equal to 90% of the discharge nozzle diameter. Long and fibrous solids pass through the pump without causing it to clog. Some examples: shavings, grass and plant parts, textile fibers, bags, cords, bones and butchery parts, leather parts in the tanning industry, tomatoes with skin and stem, apples and other fruits, green leafy vegetables, onion and potato skins, feathers, straw, food scraps, plastic parts or bottles, glass waste, wooden parts and shavings, sewage, etc.
  • Wide range of applications – designed for the chemical, steel, petrochemical, food, sugar, and seawater desalination industries, as well as for hot water distribution and power 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 RC centrifugal pump construction.

1. Reinforced bearing (ISO5199 – EN25199)
The bearing housing is standardized according to EN ISO 5199 and guarantees a shaft deflection of <0.05 mm and at least 18,000 hours of operation. It is designed to optimize axial and radial pressures and drastically reduce operating temperature. All bearing housings are adapted for the use of a reinforced “HD” bearing version, which can operate up to 100,000 working hours. The “HD” bearing is a combination of an angular contact bearing and a roller bearing.

2. One casing, 12 sealing systems
For each pump size, a unique casing can accommodate any type, brand and seal selection. The sealing chamber dimensions have been designed to guarantee effective and correct liquid circulation. By changing a few components, the sealing arrangement can be easily modified, making the pump ready for new plant or process requirements and reducing spare parts inventory.

3. High abrasion resistance
The pump body construction has been improved to allow pumping of liquids even with abrasive solid suspensions.
The internal smooth surface of the pump body prevents material build-up, and the dimensions of wear-prone components have been carefully analyzed to guarantee long-lasting and reliable operation.

4. Free passage of large solids
Free passage up to 90% of the discharge opening diameter: thanks to the impeller retraction, it allows the passage of spherical solids up to 90% of the discharge port diameter. Long and filamentous solids pass through the pump without the risk of clogging.

Design versions

 

RCM

Salvatore Robuschi RDM Industrial Monoblock Centrifugal Pumps with Closed Impeller

Monoblock version with standard B5 electric motor.

RCL

Salvatore Robuschi RDL Close-Coupled Industrial Centrifugal Pumps

Version with independent support with bearings in oil bath and mounting flange for coupling with flanged motor. This version is available for motor sizes up to IEC 160.

RCB

Salvatore Robuschi RDB close-coupled industrial centrifugal pumps with independent frame.

Shaft version: pump with independent bearings lubricated with oil or grease, coupling (short or spacer), base and motor.

RCV

Industrial Vertical Close-Coupled Centrifugal Pumps Salvatore Robuschi RDV

Vertical version with intermediate sleeves.

RCC

Industrial cantilever vertical centrifugal pumps Salvatore Robuschi RCC

Cantilever vertical type.

Types of seals

A cylindrical chamber built according to EN-12756 can be equipped with any type of mechanical seal.

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.

Cartridge mechanical seal in Salvatore Robuschi centrifugal pumps. Cartridge seal

A cartridge seal resembles a standard seal, but the stationary part of the cartridge seal is built into the housing, and the rotating part is mounted in a sleeve sealed with an O-ring. The cartridge seal housing is a mounting element in the pump, which eliminates the need to install a seal cover.

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.

  • Technical specifications

  • Typical applications

  • Product features

  • Operation principle

  • Construction

  • Design versions

  • Types of seals

Pump capacity: up to 800 m3/h
Lifting height: up to 60 m
Maximum working pressure: 10 bar
Temperature: up to 180 °C – depending on the pumped medium
Viscosity: up to 1000 cPs
Discharge nozzle: from DN 32 to DN 250
Impeller type: Vortex with free passage up to 180 mm
Materials: Grey Cast Iron GJL250 or AISI 316
Optionally: AISI 304, AISI 904, Duplex, Superduplex, Hastelloy B or C)

Performance curves

Video