Give us a call at 41 or send email to arrange an inspection/evaluation of your equipment.“The Mountain Lion version of OS X Server marked the end of a transition for Apple’s server software,” Andrew Cunningham reports for Ars Technica. Caloris can help with such evaluations, following up with recommendations for system performance improvement. If you are experiencing lackluster evaporator performance, a review of your system will help locate leaks. Air will tend to get trapped at the ends of a shell-and-tube heat exchanger due to insufficient venting (and most commonly the bottom since air is denser than steam), preventing steam from getting into that end of the heat exchanger and allowing the surface of the shell to become cool to touch. Where you see the bubbles being sucked into the machine, you have found your leak.Īlternatively, with shell-and-tube heat exchangers you can CAREFULLY touch the outside surface of the ends of the heat exchanger. Spray around suspected leak sites, just like you would inspect a tire for a leak. One simple method to assess a suspected air leak location is to use a squirt bottle containing soapy water. Ultrasonic leak detectors are the most effective method for inspecting an entire evaporator system for possible leaks, although they do require training and some experience to use properly.

If you are in a quiet environment, walk around while the system is under vacuum and listen for the “hissing” sound of an air leak.įor existing equipment, it’s often not possible to shut everything down to inspect as above.

The next day, what is the vacuum level? It is normal to lose 1/2″ mercury per hour - anything higher and you most likely have a leak.

Run the system, pull vacuum and then shut the unit down.

If you have a new piece of equipment and have the ability to shut it down overnight, do the following: Now that we know why air leaks in your system are a concern, where should we try and find them?Ĭommon sources of air leaks into your evaporator include: Air can also create an insulating layer at the heat transfer surfaces, acting as an insulation layer that impedes efficient heat transfer across the heating surfaces unless proper venting draws that non-condensable gas (air) away from the heat transfer surfaces.Proper venting of the non-condensable gases from the shell-and-tube heat exchangers is critical to maintain efficient evaporator performance. Non-condensable gases tend to collect at the ends of shell-and-tube heat exchangers, also referred to as “calandrias” when used in a falling film evaporator.

Even a small volume of air leaking into an evaporator under vacuum will significantly expand, and displace steam away from contacting the heat transfer surfaces of the evaporator heat exchangers where the steam needs to condense in-order to deliver its Latent Heat.Air, a gas that is denser than steam, also expands in volume under vacuum, comparable to steam in its amount of volume increase.The specific volume of steam dramatically increases under vacuum, meaning 1 Lb of steam occupies significantly more volume inside the shell of a heat exchanger when it is under vacuum.By comparison, air is a non-condensable gas that can only deliver Sensible Heat to a heat transfer surface, making air a much less effective gas for heating an evaporator.Steam is an efficient means of delivering heat for an evaporator system, as 1 Lb of steam delivers ~ 1000 BTU’s of Latent Heat energy when it condenses from vapor to liquid phase.less than atmospheric pressure)? It allows us to “boil” and evaporate water from a product at a lower temperature. Here are a few basics that are useful to understand:

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