Liquid Ring Vacuum Pump and Compressor

1. Introduction to Sterling SIHI liquid ring vacuum pumps, liquid ring compressors and systems:

The Sterling SIHI Group is a multinational group headquartered in Germany that specializes in fluid system engineering products and systems, with annual group sales of 500 million euros. SIHI is one of the leading fluid-technology companies; its key products are vacuum pumps and vacuum solutions, serving markets including basic chemicals, fine chemicals, energy, steel, pharmaceuticals, electronics, photovoltaics, food and general industry.

SIHI Pumps (Shanghai) Co., Ltd. is a wholly owned subsidiary of Sterling SIHI, with a complete team of experts for manufacturing, assembly, testing, sales and after-sales service in the Chinese market, guided always by the principle of "customer satisfaction".

2. Working principle of liquid ring vacuum pumps and compressors:

The impeller of a liquid ring vacuum pump (liquid ring compressor) is mounted eccentrically inside a cylindrical body. As the pump runs, centrifugal force gives the liquid inside the pump kinetic energy, forming a liquid ring that clings to and is concentric with the body.

The liquid ring and the rotor blades form a number of working chambers whose volume changes cyclically, so the fluid acts like a piston as it enters and leaves each chamber. As the liquid leaves a chamber, gas is drawn in from the inlet through a port plate; conversely, as the liquid ring flows into a chamber, the gas is compressed and discharged through the outlet.

During operation, working liquid (usually water) must be continuously replenished to carry away the large amount of heat generated during gas compression and to make up for the portion of working liquid discharged together with the gas; the working liquid can be recirculated.

3. Features of liquid ring vacuum pumps and compressors:

• Capable of handling almost all gases and vapors, and can carry a small amount of liquid.
• The impeller is the only rotating part, with no friction between metal parts, giving a longer service life.
• No lubrication is required inside the working chamber, so operation is oil-free and pollution-free.
• Compression is nearly isothermal; the liquid ring is not easily vaporized, giving high safety.
• A wide choice of materials (such as cast iron, stainless steel, Hastelloy, titanium, etc.) suits a variety of operating conditions.
• Easy to install and maintain, with high structural and operational reliability and safety.
• Can safely handle flammable, explosive and toxic gases (compliant with international ATEX certification).
• For leak-free duties with highly toxic media, the SIHI magnetically driven liquid ring vacuum pump provides an excellent solution.
• Low operating noise and low vibration.
• Integrated drainage for easier maintenance.

4. Performance parameters:

Vacuum pump:

Compressor:

Features of two-stage vacuum pumps and compressors:

• With two-stage compression, the compression ratio of each impeller is small (only 5-6 per stage), giving higher reliability during operation.
• The small per-stage compression ratio better prevents cavitation while achieving a greater pressure differential and higher discharge back-pressure.
• The working liquid temperature rise is small, so water temperature has less effect on inlet pressure and suction capacity, better ensuring the required inlet pressure.
• Cavitation is avoided more effectively, giving a longer service life with lower vibration and noise.

Structural features of the magnetically driven vacuum pump (LEM/LEH/LPH):

The Sterling SIHI liquid ring vacuum pump is designed by combining an advanced magnetic-drive coupling concept. The unique Sterling SIHI leak-free vacuum pump not only makes liquid handling more economical but also causes very little environmental pollution, because SIHI is a leak-free magnetic vacuum pump. Sterling SIHI continues to strive to be the leader in vacuum magnetic pumps across every field.

The SIHI magnetically driven liquid ring vacuum pump is a demanding, highly tight, simple and efficient vacuum pump. Liquid-lubricated and liquid-cooled sleeve bearings of tungsten and silicon dioxide materials provide axial and radial support to the shaft. The use of high-energy-density, high-grade magnetic-drive materials ensures transport safety during start-up and overload. The modular magnetic-drive system offers a range of options for different operating environments. The main pump components and the connection dimensions are the same as those of the standard pumps, and the materials can be designed to suit different environments.