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airlock

An airlock, air-lock or air lock, often abbreviated to just lock, is a compartment with doors which can be sealed against pressure which permits the passage of people and objects between environments of differing pressure or atmospheric composition while minimizing the change of pressure in the adjoining spaces and mixing of environments. The lock consists of a relatively small chamber with two airtight doors in series which do not open simultaneously.
An airlock may be used for passage between environments of different gases or different pressures, or both, to minimize pressure loss or prevent the gases from mixing.
An airlock may also be used underwater to allow passage between an air environment in a pressure vessel and the water environment outside, in which case the airlock can contain air or water. This is called a floodable airlock or an underwater airlock, and is used to prevent water from entering a submersible vessel or an underwater habitat.
Air-locks are used in space flight, saturation diving accommodation, hyperbaric chambers, submarines, some underwater habitats, cleanrooms, and pressurised caissons and tunnels. Depending on the pressure difference, when people use an airlock to transfer from higher to lower pressure, it may be necessary to follow a decompression schedule to avoid decompression sickness. A similar arrangement may be used for access to airtight clean spaces, contaminated spaces,or unbreathable atmospheres without necessarily having a pressure difference. In these cases a decontamination procedure and flushing takes the place of pressure changes.
The procedure of entering an air-lock, sealing it, equalising the pressure, and passing through the inner door, is known as locking in. Locking out is to unseal the outer door after equalising pressure and exit the lock compartment to the ambient environment. Locking on and off refer to transfer under pressure where the two chambers are physically connected or disconnected prior to equalizing the pressure and locking in or out.

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  1. J

    Hot water tap for bath has lost pressure

    Hi, can someone offer advice? Problem: The pressure for the hot water tap to the bath (this is seperate to the en-suite) has lost pressure, since modificatioins to the seperate en-siuite. History: I decided to change the scource of heating the hotwater, for the en-suite shower. The original...
  2. G

    Christmas Disaster!

    Can anyone give me an opinion on what is going on with our plumbing please? We live in a very old cottage, we have no central heating - just a hot water tank with an immersion heater. This heats the water for the bathroom basin and kitchen sink. The shower heats its own water separately. At...
  3. P

    new 3 port mid pos valve but no heat downstairs

    just replaced mid pos 3 port valve in a rented house for my mate who owns it. Had to re-wire the complete system as it was so out of date but although the new valve etc works, the rads downstairs dont come on at all. Rads upstairs are fine and flow and return at boiler are normal. I didnt have...
  4. W

    mixer shower cw prob

    fitted ensuite couple months back, had call from customer telling me no c/w coming from mixer shower occasionaly, only hot (concealed mixer). investigated to find c/w will run but not everytime shower turned on. turned mixer to cold, turned on shower, no c/w. went into bathroom and turned on...
  5. M

    No cold water from mains

    HI chaps I changed a kitcheen tap today and apart from an airlock in the hot side which i blasted out through the washing machine taps it all went fine. Customer has rung back saying that cold taps in bathroom (its a bungalow) have not cold water (WC bath and basin) bit kitchen is working...
  6. A

    Damsel in distress

    Hi everyone, Hope someone can help as I am sinking in escalating probs:( Friend fitted new kitchen tap for me couple of weeks ago, water only came out in a trickle so he suggested a pump which would also help shower flow. He fitted a large pump which rendered shower too hot to use even at...
  7. K

    Hot water tank/heatexchanger

    Hi, new to forum and seeking help. Got an indirect system with a hot wtertank or heatexchanger in cupboerd upstairs. Problem is tank has started making a god awful roaring noise as if its goin to take off:eek:. This goes on for a few seconds then noise stops and blows back into expansion tank in...
  8. T

    Blocked System

    Hi It all started when I re-connected a radiator that had been out of the system for some time. When I bled the radiator all seemed ok. Then the system stopped and all went cold. I have checked programmer, boiler, roomstat and tankstat and all function as they should. Suspected an air lock so I...
  9. M

    primary flow with cold feed and vent into it?

    Hi guys, today my boss has told me to pipe up a boiler with the primary flow having the vent pipe and cold feed going into it. Is this ok? The pump is on the flow pumping downwards. He says that if the cold feed goes into the return then the pump will pump the water through the coil and back...
  10. D

    poor circulation - please help

    I've just fitted a new worcester 24i Junior in a small flat (only 5 radiators). The radiators are on 8mm microbore but don't know if they are individually connected to the flow and return or via a manifold. The boiler is apparently working fine - pressure is stable, hot water fine. In C/H mode...
  11. P

    Glowworm Cxi combi probs

    A mate has had a plumber come in and move two rads. My mate has turned heating on and its not working, he isnt sure if the guy tested it before he left. Boiler was installed 18 months ago and by a cowboy no paperwork filled in and it hasnt been notfied! Anyhow when demand for heating the...
  12. C

    Faulty boiler

    Hello, I am having problems with a Worcester Greenstar si boiler, the hot water works fine but the boiler instantly switches off when I turn on the heating. The pump is working and there is no air in the system and there is no room stat. The flow pipe coming out of the bottom of the boiler is...
  13. M

    Trickling cold water and no access to CWSC

    Hi all, this is my first post. I've replaced a bath/shower mixer for a friend who lives on the ground floor in a 1930's maisonette. I had to drain down the cold water cistern to do it as the woman who occasionally lives upstairs is a bit strange and after a number of disputes won't let him have...
  14. S

    Lesson Learned

    Today, I was installing a new sink, it was a Blanco and the fitting were not standard sizes so this caused a headache. The sink was too big for the kitchen unit but the customer said "make it fit" so using my magic powers succeeded. Re-connected the new taps had a bit of a leak which...
  15. C

    Cold Radiator

    Hi all, I have recently refilled my hot water & central heating system after fitting a new 2 port valve. All of the radiators are hot with the exception of the one in the kitchen downstairs, I have bled them all so am clueless as to why this one rad remains cold? Any ideas?? Regards
  16. N

    No CH

    When I call for CH the boiler does not fire up. HW is fine and when on all the rads upstairs get hot. Its an S plan system with the pump on the return. The pipes are hot past the valve that should control the CH. Would I be right in thinking this valve is passing and not talking to the boiler...
  17. H

    Added rad to existing openvent system/system will not fill

    adding an additional radiator to existing system. drained system down,added new rad downstairs. filled very slowly, E & F filled quickly, boiler is a potterton prima b with pump above. checked the drain off on the return to pump very little water came out. thinking of reverse filling from drain...
  18. M

    where can I drain microbore open system

    all rads have no drain points as flow/ return pipes enter/exit on same side of rad - any ideas?
  19. N

    Three port valve

    Hello all, I've just replaced a hot water cylinder so had to drain down the central heating system. Prior to me doing this work the flat occupier was having trouble with the radiators coming on when only the hot water was set to come on. This was diagnosed as the need for a three port valve...
  20. J

    Dripping noise

    Hi, hope you can shed some light on this mystery. My mother has recently had a new combi boiler installed, since it has been in she can hear a constant dripping noise coming from the inside of the walls. The installer came back out but he said there was nothing visibly wrong with it, and he...
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