01 / Technical selection
Draw the liquid path and the gas path separately
Start with two drawings. The liquid path runs from the feed connection through the product distributor, the vessel, the level-control region and the discharge pump to the next machine. The gas path runs from the vessel headspace through the vacuum connection, any condenser, the vacuum source and the exhaust route.
Separating the paths prevents a common omission: the discharge pump is treated as a downstream item while the vacuum source is treated as a utility. Both are part of the same pressure boundary. The pump suction sees the vessel condition, and the pump outlet must meet the pressure required by the next process step. A change on either side can alter level control, foaming or gas release.
The liquid drawing should also show sample points, drains, cleaning connections and any buffer or recirculation loop. The gas drawing should show where condensate is collected, how it is removed and whether any recovered volatile fraction is returned to the product. Those details belong in the interface discussion, not in separate supplier notes that are never compared.
For a multi-product line, mark which parts of the drawing change between recipes. A clear juice and a thick puree may use the same vessel outline but different distribution, discharge and cleaning arrangements. The interface brief should expose those differences before a quotation is compared.
02 / Technical selection
Define the vapour load before choosing the condenser
The vacuum system handles gas released from the product and vapour formed under reduced pressure. The vapour fraction depends on the product temperature, the pressure and the amount of flash that occurs. The orange-juice chapter describes vacuum flash deaeration as evaporating a small fraction of the liquid, with the vapour containing volatile flavour components that may be condensed and returned.
That description is a useful starting point, not a universal condenser specification. A higher inlet temperature can increase the vapour load. A product with a different volatile profile may require a different recovery decision. Available cooling-water temperature and the permitted exhaust route also constrain the arrangement.
Record what is known about foaming and entrained gas. The orange-juice chapter notes that foam can build up when product moves from a higher-pressure line into the lower-pressure vessel, especially with pulp or dispersed gas. If foam fills the available headspace, deaeration can become unstable. The interface brief should say whether foam behaviour has been observed, estimated or remains untested.
Do not select a condenser from a photograph or from another product's duty. State the vapour load basis, the cooling service and the quality objective. If the data is incomplete, mark the condenser as an open engineering item rather than presenting an assumed design as final.
03 / Technical selection
Make the discharge pump part of the vacuum boundary
The discharge pump must move product out of the vessel while maintaining the level and pressure conditions the process needs. Its suction condition is not the same as a pump drawing from an open tank. The quotation should identify the pump type, the product-contact materials, the seal arrangement and the available suction condition.
The outlet side needs equal attention. Record the pipe size, transfer distance, static lift and pressure required at the next machine. If the product passes through a heat exchanger, buffer or filler, the highest downstream pressure may not occur at the deaerator outlet. The pump and control valve arrangement must cover the actual operating range.
Viscous or particulate products can change the pump duty. A pump that handles clear juice may not handle a puree with fibres or pieces without damage or blockage. Share the viscosity method, particle size and shear limits with the equipment review. A trial may be needed when the product behaviour is outside available experience.
Level control links the inlet, the vessel and the discharge. Describe how the control responds to startup, low flow, product changeover and cleaning. A stable level in steady production does not prove that the same arrangement will work during a sudden reduction in downstream demand.
04 / Technical selection
Name the utility and control responsibilities
An interface brief is also a responsibility map. For each utility, state who supplies the connection, who defines the consumption and who confirms the available capacity. The list commonly includes electrical power, cooling water, compressed air, vacuum exhaust, drain or condensate handling and any cleaning services.
The control interface deserves the same treatment. List the signals the deaerator sends to the line and the signals it expects to receive. Examples include run command, flow or level status, vacuum status, alarms, discharge-pump feedback and cleaning-mode selection. The exact list follows the chosen configuration; the brief should not pretend that a generic list is a final control design.
Agree the boundary between equipment supply and site installation. Who provides the vacuum source, the condenser, the discharge pump, the instruments, the local panel, the interconnecting pipework and the commissioning support? Ambiguity here often appears later as a missing item in the project schedule.
Keep the utility schedule tied to the selected configuration. A reference image can show the general arrangement, but it cannot establish pipe sizes, electrical ratings or cooling-water consumption. Those values belong in the quotation and the agreed drawings.
05 / Technical selection
Close the brief with cleaning and downstream pressure
The product path that must be cleaned includes the distributor, vessel internals, level instruments, discharge pump, sample valves and low points. The gas path may also need a service or cleaning procedure depending on the product and the condenser arrangement. Ask how cleaning liquid reaches each intended surface and how the circuit drains.
Describe the cleaning sequence the site intends to use, including the services, temperatures, flow and changeover schedule. Confirm which parts are cleaned in place and which require manual access. A stainless surface alone does not establish cleaning performance, and a CIP connection does not prove that every product-contact area is covered.
Downstream pressure is the final part of the liquid path. The deaerator may discharge to a buffer, heat treatment, homogenisation or filling. Each interface has its own pressure and control condition. If the downstream machine can impose a higher pressure than expected, the discharge pump and control arrangement must be reviewed for that case.
Protect the product from air after deaeration as well. A closed transfer, appropriate tank blanketing or a short protected path may be part of the line design. The equipment brief should identify where that protection ends and who is responsible for it.
06 / Technical selection
Treat the interface brief as a review document, not a datasheet
The completed brief should show the two paths, the named interfaces, the known operating range and the open questions. It should distinguish measured data from estimates and product-specific observations from general principles. That makes it useful for comparing quotations without pretending that every supplier is offering the same scope.
Use the brief to run a simple completeness check. Is the inlet condition defined? Is the gas path complete? Is the discharge pressure known? Are foaming and vapour loads addressed? Are cleaning and controls assigned? Are the utilities and exclusions visible? A negative answer is not a failure of the review; it is an item to close before purchase.
The cited orange-juice chapter is valuable because it connects oxygen, foam, vapour and condensation in one process description. Its examples remain orange-juice examples. A thick puree, a pulpy nectar or a sauce with particles needs its own product data and, where necessary, its own trial.
A good interface brief does not make the equipment generic. It makes the connections explicit, so the vessel, vacuum system, condenser and discharge pump can be reviewed as one operating arrangement.
Evidence
Sources and further reading
- Tetra Pak Orange Book, Chapter 4: Principles of processing orange juiceorangebook.tetrapak.com
Sections 4.2, 4.2.2 and 4.2.3 connect air entry, foaming, vacuum flash, vapour condensation and oxygen measurement. Product-specific observations are not transferred to other fruit without trials.
- FAO Agricultural Services Bulletin 146, Chapter 6: General juice manufacture principlesfao.org
Section 6.1.7 describes deaeration after aeration-prone extraction steps and the need to protect the product from air afterwards. Historical principles, not an equipment guarantee.
Source links identify the material used for this editorial note. They do not imply endorsement of this site or of any equipment configuration.
From process note to equipment brief
Review the deaerator against your product.
Send the liquid, flow range, temperature and the air or oxygen problem you need to solve. The configuration review can start with incomplete data.