Wiegand Steam Jet Cooling Plants
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Wiegand® Steam Jet Cooling Plants Cooling under vacuum engineering for a better world

Cooling is an expensive process. Ongoing increases in energy costs demand alternatives to traditional systems (mechanical compressors). More and more, flash cooling plants offer an environmentally friendly and economical GEA Wiegand has more than fifty years of experience in the design and construction of flash cooling plants. GEA Wiegand reference plants: aqueous nitric acid/phosphoric acid aqueous plaster suspension calcium milk barium hydroxide solutions various waste waters fruit juice The steam jet cooling plants may have a capacity between approximately 10 and 20 000 kilowatts. As an...

Steam Jet Cooling Plants – Construction Details and How They Work B 1 Fig. 1: Diagram of a steam jet cooling plant with mixing condenser A flash vessel B steam jet compressor C mixing condenser Advantages of flash cooling plants simple and robust construction reliable and safe to use very little wear and tear owing to no moving parts minimal maintenance direct and indirect cooling is possible; with indirect cooling, the cooling medium is almost always water and therefore easy to handle motive steam medium to be cooled chilled medium cooling water warmed cooling water very low chilled-medium...

Steam Jet Cooling Plants – Construction Details and How They Work Vapour compression using jet pumps Jet pumps are compressors driven by a fluid and have no moving parts: the vapour, flashed from the suction medium (i. e. the medium to be cooled) passes through the suction nozzle, into the head of the jet pump. The motive medium (usually steam) is expanded, after passing through a motive nozzle, where the pressure energy is transformed into kinetic energy. This energy stream impinges with and conveys the suction medium (i. e. the medium to be cooled), accelerating it into the inlet cone of...

Steam Jet Cooling Plants – Types Basically, there are three different types of steam jet cooling plants: compact design for small capacities; column design for medium capacity and large capacities where there is little floor area; bridge design for high capacities. Steam jet cooling plants of compact design These consist of horizontally designed equipment: one flash vessel (1) and one condenser stage (2) being installed in a common horizontal vessel. The jet pump (3) is arranged in parallel to this vessel. A small liquid ring vacuum pump (4) is installed as a deaeration unit. The...

Steam Jet Cooling Plants – Types Steam jet cooling plants of column design These are of vertical construction: flash cooling chamber (1) and condenser chamber (2) are mounted one on top of the other. The flash vessels and the condenser chambers of each stage are connected to each other through piping or a jet pump for vapour compression (3). In many cases, a cooling tower (6) is installed in order to re-cool the cooling water. Generally, a steam jet vacuum pump is provided as a deaeration unit. The plant is controlled by an operation control system. This type of design requires a relatively...

Steam Jet Cooling Plants – Types Steam jet cooling plants of bridge design These consist of vertically or horizontally arranged flash cooling chambers (1), horizontally mounted jet pumps (3) and vertically designed condenser chambers (2). The flash vessel and condenser chambers of each stage are connected by piping or a jet pump for vapour compression (3). In many cases, a cooling tower (6) is included for re-cooling of the cooling water. A steam jet vacuum pump for deaeration is also included. The plant is controlled by an operation control system. This type of design requires relatively...

Steam Jet Cooling Plants – Types Standardised steam jet cooling plants – sizes GEA Wiegand offers standardised plants. Advantages: simple design low investment costs shorter delivery times Eight standardised sizes are available for particular applications (table). Tailor-made design is available on request. The given dimensions refer to the pictures on the right/ next page (fig. 11, fig. 12 and fig. 13). Medium to be cooled (water) inlet temperature outlet temperature volume flow nozzle sizes: inlet/outlet Cooling water inlet temperature outlet temperature volume flow nozzle sizes:...

Steam Jet Cooling Plants – Types

Installation and Control Possible combinations Cooling plants usually consist of three components: cooling plant itself circulation of the chilled medium circulation of the cooling water Most of the flash cooling plants are operated under vacuum. The chilled medium and/or the cooling water must then be conveyed from that vacuum and fed into the relevant circulation process. A barometric arrangement allows a particularly simple discharge from the vacuum. If however, a minimum 11 m height for this arrangement is not available, than nonbarometric installation is required (page 11). The table...

Installation alternatives Installation may be barometric or non-barometric: Fig. 15: Non-barometric Installation cooling water motive steam The suction pressure of the circulation pump is always higher than or equal to atmospheric pressure, therefore hardly any risk of cavitation. The vacuum chamber is only separated from atmospheric pressure by liquid column in the barometric leg. Usually this system cannot considered as pressure vessel because this arrangement does not allow the build up of over-pressure. Note: The installation height of the vacuum chambers must be at least 11 m above the...

Control of steam jet cooling plants Steam jet cooling plants are controlled in order to match the chilling capacity to the relevant demand and/or to reduce operating costs. Fig. 16: Maximum temperatures of the re-cooled water over one year (central Europe) Capacity control The capacity of a steam jet cooling plant can be altered by turning on/off the motive steam valves of the individual jet pumps. Assuming a constant flow of the medium to be cooled, the chilling capacity can be controlled in accordance with the temperature of the chilled medium at the outlet of the steam jet cooling plant....