Steam Jet Ejector Vacuum Systems

Single-Stage Steam Jet Ejectors are based on the ejector-venturi principle. In operation, steam issuing through an expanding nozzle has its pressure energy converted to velocity energy. A vacuum is created and the high velocity of steam entrains air or gas and the mixture of gas and steam enters the converging end of the venturi, passes through the diffuser where its velocity energy is converted into pressure sufficient to discharge against a predetermined back pressure.

Single stage steam jet ejectors are used to create vacuum covering 40 mm Hg. Absolute.

Two Stage Ejector with Condenser - The system is the assembly of two units whose construction is similar to single stage with inter condenser (direct contact type or surface type). Steam of the first stage is expanded through nozzle entrains the air or other gases and discharges them to diffusers at a higher pressure in the condenser. The discharge from the first stage will then directed to condenser which reduces volume of discharge gases. These gases turn discharged with the help of second stage ejector. The ejector is required to be placed at sufficient height to drain the ejector condenser barometrically. If barometric installation is not possible then an extraction pump is provided to drain the condenser in vacuum. The discharge or exhaust steam and entrained gases is directed to the atmosphere or can be condensed by an after condenser or lead to a water tank if required.
 
 Absolute Pressure Range: Vacuum from 100 MM HG Absolute to 10 MM HG Absolute.

Three Stage Ejector is similar in construction as of Single Stage Ejector, but having intermediate condensers. Three Stage Ejector comprises of Booster Ejector, Booster condenser and a Two Stage Ejector. And Two Stage Ejector consists of a high vacuum ejector, a inter condenser and a low vacuum ejector.

This system will give higher vacuum and can handles larger quantity of condensable vapors. Gas or Gas vapor mixture is discharged from the first stage into the condenser where the operating steam is condensed and gases are cooled. The cooled gases are then entrained by the second stage and discharged into the second inter condenser. Here, the steam used in the second stage is condensed. The gases are finally entrained by the third stage and discharged to atmosphere.

Absolute Pressure Range : Vacuum from 5 MM HG Absolute to 15 MM HG Absolute

Four Stage Ejector with Condenser : Four Stage Ejector is having construction and working similar to Single Stage, Two Stage & Three Stage Ejector. When ejector is to be installed at low ambient temperature area, primary booster should be steam jacketed to prevent building up of ice on the diffuser internal bore. Sometimes both primary and secondary boosters are completely jacked to avoid deposition of product inside the ejector.

The Four Stage Ejector consists of following components :

• Primary Booster Ejector
• Secondary Booster Ejector
• Booster Condenser
• Vacuum Ejector
• Inter Condenser
• Low Vacuum Ejector

Absolute Pressure Range :

• Vacuum from 0.5 MM HG Absolute to 5 MM HG absolute

Five Stage and Six stage Steam Jet Ejectors with Condenser - Five stage and six stage ejectors are designed for absolute pressure in Micron Range. The arrangement of these ejectors is similar to the four stage ejector with additional one or tow non condensing stages.

Absolute Pressure Range :

• In Micron as per customer requirement.

Special Precautions while measuring Low Absolute Pressures :

• Do not use spring type vacuum Gauges
• Ensure that the guage tubes are clean and free form contamination
• Ensure that the guage liquid is clean and free from contamination