Centrifugal pumps with closed impeller – RD series

Centrifugal pumps with closed impeller – RD series

SPEAK TO US TODAY +27 31 701 52 55

Salvatore Robuschi RD series pumps are centrifugal process pumps with a closed impeller designed with a modular construction to reduce spare parts and storage costs. They are designed in accordance with ISO 2858/5199. All pumps in this series have one sealing housing for all types of seals (single, tandem, cartridge, “back to back” or packing, also PLAN according to API 682). They are characterized by: modular design, interchangeability of parts, wide selection of seals and the ability to pump under low NPSHa conditions.

Pomps are used in applications with aggressive chemicals, suspensions, high temperatures, high viscosity and high specific gravity. They can pump aggressive organic and inorganic liquids, e.g. in the chemical, petrochemical and steel industries.

Salvatore Robuschi RD series pumps are centrifugal process pumps with a closed impeller designed with a modular construction to reduce spare parts and storage costs. They are designed in accordance with ISO 2858/5199. All pumps in this series have one sealing housing for all types of seals (single, tandem, cartridge, “back to back” or packing, also PLAN according to API 682). They are characterized by: modular design, interchangeability of parts, wide selection of seals and the ability to pump under low NPSHa conditions.

Pomps are used in applications with aggressive chemicals, suspensions, high temperatures, high viscosity and high specific gravity. They can pump aggressive organic and inorganic liquids, e.g. in the chemical, petrochemical and steel industries.

Technical specifications
Pump capacity: up to 500 m3/h
Lifting height: up to 140 m
Maximum working pressure: 16 bar (up to 20 bar for non-aggressive media)
Temperature: up to 220 °C – depending on the pumped medium
Discharge nozzle: from DN 32 to DN 125
Impeller type: closed
Pump materialss: AISI 316, Duplex SAF2507
Optional: AISI 304, AISI 904, Superduplex, Hastelloy B or C
Typical applications
Industry Application example
Chemical industry Unloading tanks, pumping mixtures of nitric acids, urea solutions, ethylene dichloride, pumping biodiesel, sulfuric acid, acetic acid, glycerin.
Oil and gas refining and extraction industry Pumping aviation fuel in the ATEX zone, transfer of chemical solutions in refinery dosing stations.
Wastewater treatment Transfer of acidic wastewater in vacuum evaporation plants, pumping of clean water in wet scrubbers.
Food industry Pumping superheated water (130°C) in pasteurization processes, pumping liquids in CIP processes, transferring residual liquid from fat rendering, press water in fish processing, as well as pumping palm oil, brines, ethyl alcohol.
Product features

The RD series pumps are centrifugal process pumps with a closed impeller. The main features of this series are: modular design, interchangeability of parts, a wide selection of sealing systems, but also the interchangeability of the hydraulic design and the ability to pump under low NPSHa conditions.

The RD series centrifugal pumps are designed with a modular construction in mind in order to reducing spare parts and storage costs. Many devices use common spare parts. These pumps are designed in accordance with ISO 2858/5199 standards, making them interchangeable with other machines manufactured to these standards. In addition, all Salvatore Robuschi centrifugal pumps have one seal housing for all types of seals. By replacing a few components, the pumps can be equipped with single, tandem, cartridge, back-to-back or packing seals. The seals can be equipped with a PLAN according to API 682 (e.g. PLAN 11, PLAN 52, PLAN 53, PLAN 54).

  • Modularity and easy maintenance – 3 bearing housing and shaft groups covering 35 different pump sizes. Replaceable wear plate ensures long pump life and reduces maintenance costs. In addition, the bearing housing allows adjustment of axial clearance on the drive side. Oversized bases provide high stability, and the mounting flange design avoids problems associated with pump and motor misalignment.
  • Performance – investment cast impellers for high hydraulic efficiencies and low NPSH values.
  • Flexibility12 different sealing systems can be installed in one body cover.
  • Wide range of applications – designed for the chemical, steel, petrochemical industries, for seawater desalination plants, 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 RD centrifugal pump construction.

1. Reinforced bearing (ISO5199 – EN25199)
The bearing housing is standardized according to EN ISO 5199 and guarantees shaft deflection < 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 for 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 sealing choice. The dimensions of the sealing chamber 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. One casing, two impellers
Each pump size can use a unique casing that applies to both closed (fitted with a wear ring) and open (with a replaceable wear plate) impellers. This versatility allows the pump to be easily applied in new installations and processes.

4. Wear plate and adjustment
The pump is equipped with a replaceable wear ring.

Design versions

 

RDM

Salvatore Robuschi RDM Industrial Monoblock Centrifugal Pumps with Closed Impeller

Monoblock version with standard B5 electric motor.

RDL

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.

RDB

Salvatore Robuschi RDB industrial centrifugal pumps with closed impeller and independent frame.

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

RDV

Vertical Close-Coupled Centrifugal Pumps Salvatore Robuschi RDV

Vertical version with intermediate sleeves.

Seals types

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

  • Seals types

Pump capacity: up to 500 m3/h
Lifting height: up to 140 m
Maximum working pressure: 16 bar (up to 20 bar for non-aggressive media)
Temperature: up to 220 °C – depending on the pumped medium
Discharge nozzle: from DN 32 to DN 125
Impeller type: closed
Pump materialss: AISI 316, Duplex SAF2507
Optional: AISI 304, AISI 904, Superduplex, Hastelloy B or C

Performance curves

Video