Liquid Jet Exhauster
Using a liquid to aerate, entrain gases, create vacuum and prime pumps
Liquid Jet Exhausters
Liquid Jet Exhausters are simple, efficient and versatile devices for vacuum pumping, aerating or mixing liquids and gases. Using liquid under pressure as the only motive force, these units are ideal for handling mixtures of condensable and non-condensable gases.
Exhausters are manufactured in two varieties, a Single Nozzle Exhauster and a Multi Nozzle Exhauster. Single nozzle exhausters are standard units, and are similar in design to the Liquid Jet Eductor. Multi nozzle exhausters have much higher air or vapor handling capacities at lower pressures and are ideal where the motive liquid supply is limited.
Liquid jet exhausters are manufactured in a variety of materials such as Carbon Steel, Stainless Steel, Duplex Stainless Steel and Bronze, special materials such as Hastelloy are also available. Unit sizes range from 3/4 Inch to 6 Inch for the Type 484 Single Nozzle Exhauster, and from 3 Inch to 10 Inch for the Type 488 Multi Nozzle Exhauster. Connections for all units can be either screwed or flanged depending up on size.
No other pumping & mixing device offers all these outstanding features:
- Safe - Exhausters can be used in hazardous locations where electrically operated alternates would require explosion proofing at considerable cost.
- Low Cost - Units are small in relation to the work they do and cost is correspondingly low.
- Versatile and Reliable - Even under severe service conditions these exhausters will operate reliably. They can be used where other pumping devices would not be practical and are ideal for intermittent service.
- Self Priming - Exhausters are self-priming. They operate equally well in continuous or intermittent service.
- Easy to Install - Connections can be made to suit your piping requirements. Little space is required to accommodate units and they are normally so light in weight they can be supported by the piping to which they are attached.
- No Moving Parts - Exhausters are exceedingly simple and reliable. There are no moving parts to wear or break in a basic exhauster, and require little attention, only periodic inspection and maintenance.
- Corrosion and Erosion Resistant - Because they can be made of practically any workable material, or coated with corrosion-resistant materials, exhausters can be made highly resistant to the actions of the liquids handled or the environment in which located.
Typical Exhauster Applications
Liquid Jet Exhausters have been used in many different industries for different purposes. Generally, their applications can be divided into four main categories, each of which can be seen below:
- Pump priming
- Pumping and mixing of liquids and gases
- Evacuating closed vessels
General Note : As these devices are gernerally water driven, the motive liquid temperature is an important factor of operation. If moderate to high levels of vacuum are required consideration should be given to the motive temperature to prevent the liquid from flashing while the exhauster is operting.
The exhauster can be installed directly into pipework or alternatively mounted within a vessel or pond. The exauster can driven by the process liquid or taken directly from the vessel the exhauster is installed into via a pump, and is used to entrain air or other gasses and mix them together throughly.
Priming a centrifugal pump
The exhauster is mounted on the pump casing similar to that shown and is used to exhaust air from the casing and suction line to lift liquid into the impeller before starting the pump. In typical installations the vacuum lift required varies from that equivalent to 1.5 meters water lift to a 6 meter water lift.
This is a simple laboratory arrangement for obtaining low suction pressures with a Liquid Jet Exhauster using chilled water at about 2 degrees Celsius. Depending up on the available motive water temperatures, this system can provide suction pressures approaching 5mm HgA. Unlike other types of equipment, Liquid Jet Exhausters are compact, low in cost and require no lubrication or oil seals.
Note - the motive liquid temperature is the primary limiting factor of operation, for very low suction pressures consideration must be given to the motive liquid vapour pressure to prevent it from flashing to a gas/vapour.
Evacuating a closed tank or vessel
This is a typical system for evacuating a closed vessel. In order to reduce overall evacuation time before operating the exhauster steam can be used to flush or purge air from the vessel as the exhauster will condense any steam remaining in the treating chamber. If a steam purge is not available, the exhauster will work equally well with any condensable or non-condensable gas.