SB

Liquid Ring Compressors

- n

sb

Service liquid

Gas mixture

Compressed gas and liquid

2 3

A family of API liquid ring compressors has been developed and has been in the market for nearly a decade, they are specifically made for the Petroleum, Chemical and Gas Process Industries. The design takes into account all the applications where heat sensitivity of the gas, explosion hazard, wet gas or operational problems make impossible the use of other type of compressors. Reliability at highest level and low maintenance costs are the distinctive factors for this range of compressors.

The liquid ring technology is based on a rotor centrally positioned in an oval shaped casing. Rotor is not touching the casing in which there is a precise amount of liquid that during rotation forms a ring, caused from the centrifugal force, that follows the casing outer shape. Due to the patented oval shape the ring is filling differently the volumes in between the blades of the rotors. In two points the liquid fills completely the volumes. In between the two points the liquid is receding in the beginning and up to half way, thus creating suction, it is then advancing creating pressure. The gas is entering the casing, where suction is generated, through the inlet port and it is leaving after it has been compressed through the outlet port. The liquid that is used for sealing is flowing continuously and is fed with a dedicated line. The sealing fluid is absorbing the heat of compression and it is leaving the casing together with the compressed gas and it is separated in a discharge separator tank.

The compressor has been designed in accordance with the requirements of API 681.It is available in single stage version, with maximum discharge pressure up to 5,5 bar, or double stage version, up to 14 bar discharge pressure. True back pullout design enables maintenance of the compressor without disassembly of piping and service liquid connections. By means of cylindrical gas distributors and relative large inlet gas passages, friction losses are reduced to the very minimum. Radial forces acting on the compressor shaft are balanced from the double acting design reducing shaft deflection and vibrations. The simple but sturdy construction of the SB compressor is completed from the overhung arrangement that requires only one shaft seal and bearing housings externally accessible. This features, linked to the liquid ring technology that ensure running without metal-to-metal contact, made the SB compressor highly reliable with very low running cost.

Modelling of the impeller with acting torque

The result showing the extent of displacement

Forces, moments and pressure acting on the cover

The result showing stress on the cover

Pompetravaini-NSB API SB Liquid Ring Compressor for Gas Processing

Working Principle

Design

Each component is analyzed and optimized for the application.

SB

Liquid Ring Compressors

- n

sb

4 5

Bearing frame design in accordance with API Standard 681

- True back pullout construction allows for service of seals and bearings without removal of process piping and motor. This will shorten intervention time.- Designed with dual thrust bearings and radial bearing for maximum reliability. Maintenance cost is reduced in a sensible way.- Grease lubricated bearings are standard, Oil Mist and Oil Flooded systems are available. This advantages prolong bearings life.- Vibration probe connection points are standard design. This ensures reliable and trouble free operation of the compressor with a more economical running cost.- Bearing frame inspection and drain ports. will speed up inspection and maintenance operation thus less expensive.

Manufactured to comply with Section VIII, Division 1 of Asme code or European Standards

- Forged steel materials are utilized for all pressure containing components.- Welding procedures are performed in accordance to European or ASME code.- Full penetration welds of all pressure containing components.- Inspection procedures are performed according to International Standards and Codes.

Low startup torque and operational speed The low starting torque and low operational speed requirement, combined with a direct motor driven design, ensures a long compressor life, reducing running cost.

Robust overhung designThe rigid shaft construction requires the use of a single shaft mechanical seal. A single moving element ensures trouble free operation, thus more economical life cycle.

Impeller and casing design allow for real back-pullout repairLanding areas safely secure the impeller within the compressor allowing for the removal of the shaft. Non-interfering fit of impeller and distributor ensure the impeller will not seize. This solution ensures a less expensive maintenance intervention.

Precision design and fit of impellerNo gap adjustment is necessary to the impeller. Proper positioning is assured through product design and precise manufacturing. Result is a faster re-assembly, shortening the downtime.

Standard cartridge type mechanical seals per API StandardsAvailable with single or double mechanical seals and API seal flush plan systems. Maximum flexibility in selecting the optimum mechanical seal configuration.

High efficiency shrouded impellerImpeller designs optimizes energy transfer creating a highly efficient compression cycle. The impeller is dynamically balanced for smooth operation. This ensures a lower running cost.

Flanged connections per API standard 681All process and drain connection are flanged and conform to DIN or ANSI B16.5 norms. This feature will shorten installation time.

Innovative hydraulic design (patented) Highly efficient cylindrical distributor features large inlet and discharge ports for optimum efficiency. Eliminates the need for compensated seal flow liquid. Simple and effective then big saving in running cost.

Engineered piping arrangementFeatures self-draining vertical or tangential inlet and tangential discharge connections to eliminate the collection of condensable fluids and service liquids in the piping system.

Materials of constructionStandard compressor materials include Carbon Steel and Stainless steel, optional materials are available. This allows the optimum material selection for each specific application.

Simple and robust construction

SB

Liquid Ring Compressors

- n

sb

6 7

- The liquid ring design principle allows for the handling of saturated, corrosive or contaminated gas streams.- No contact between components, minimizes wear and reducing heat, vibration, noise and maintenance requirements.- The continuous supply of cooled service liquid removes the heat of compression and maintains thermally stable conditions for the safe compression of hazardous, explosive and thermally sensitive process gases.- Almost isothermal process allows the compressor to run at low temperatures and thus longer service life.

- Chemical- Chlor-Alkali- Chlorine Gas Compression- Carbon dioxide Compression- Drinking Water- Flare Gas Recovery- Gas Production

- Hydrogen & Phosgene Compression- Ozone & Oxygen Compression- Polymers- Pulp & Paper- Refineries- Vent Gas Compression- VCM Recovery

Standard compressor materials are carbon steel and stainless steel, other materials are available as options. Contact our sales office for additional information.

Capacity range

Engineered Compressor Systems

We supply both standard and custom engineered compressor systems. Pompetravaini-NSB engineered systems are designed in compliance with the industry standards, international code requirements and/or customer’s specifications.

The complete system design gives to the customers the confidence that each component is compatible with the system and the application.

Customer’s Benefits

Industries and Applications

Materials

16

14

12

10

8

6

4

2

0

Disc

harg

e pr

essu

re (b

ar a

)

100 1000 5000

Suction capacity (m3/h)

NA4.CC.NSB0.GB00/ZC.UD/DZ