Vacuum Pump

Good morning people in my computer.
I am trying to find and purchase a vacuum pump for the bell in a jar experiment. They are a lot of money for something that comes out once a year. Do have a have any suggestions and recommendations of one that would be suitable and not expensive.
 
We have the Refco pump (think in was from Breckland) that we have used for the last 6 years, does an adequate job with the Lascells space tube for sound in a vacuum.
We also use it in the Particles topic to show a collapasing bottle (2L fizzy drink bottle not the expensive metal one!) and expanding marshmellows/Ballons in pressure so it is used a number of times in the year.
Students like it's smiley face!
 
You could also look at getting a Guinea and feather tube (free fall in a vacuum), if you don't have one, to get more use from the pump.
 
Do you use vacuum filtration etc in Chemistry? The price can be justified once a few more uses are realised - plus they do last quite a while, so a one off expense is lessened as the years go on.
 

Peter Sigsworth

COMMITTEE
Good morning people in my computer.
I am trying to find and purchase a vacuum pump for the bell in a jar experiment. They are a lot of money for something that comes out once a year. Do have a have any suggestions and recommendations of one that would be suitable and not expensive.
We got ours from rapid but they don't do them anymore - select schools one is similar. Here is a link to our 'bell in a jar' experiement adaptations - in space no one can hear you screem!!!!!
(https://community.preproom.org/inde...tter-results-without-spending-a-fortune.4735/)
 

clairelucas

COMMITTEE
Out of interest, where do you get the oil for the jvac pump? I suspect we must have 'borrowed' from another dept, as the oil I have now used up is in a non-purposebuilt bottle. Just seems 4l is excessive (on Timstar). Is there a cheaper or more easily obtained alternate brand?n
 
Out of interest, where do you get the oil for the jvac pump? I suspect we must have 'borrowed' from another dept, as the oil I have now used up is in a non-purposebuilt bottle. Just seems 4l is excessive (on Timstar). Is there a cheaper or more easily obtained alternate brand?n
I'm still on the oil it came with.
 

Peter Sigsworth

COMMITTEE
Out of interest, where do you get the oil for the jvac pump? I suspect we must have 'borrowed' from another dept, as the oil I have now used up is in a non-purposebuilt bottle. Just seems 4l is excessive (on Timstar). Is there a cheaper or more easily obtained alternate brand?n
We got enough with the purchase and haven't needed to buy any more as yet
 
Anyone got a foolproof way of getting the sound in a vacuum bell jar experiment to work. Either the bell stops working or there isn't a good enough seal to get a decent vacuum despite copious amounts of vaseline. Our vacuum pump lets air back in (its a rotary engine pump)
 

Peter Sigsworth

COMMITTEE
Anyone got a foolproof way of getting the sound in a vacuum bell jar experiment to work. Either the bell stops working or there isn't a good enough seal to get a decent vacuum despite copious amounts of vaseline. Our vacuum pump lets air back in (its a rotary engine pump)
Ours sits on a rubber washer and doesn't need any vaseline at all. If you have trouble with the bell then change it for a battery powered personal attack alarm - the type you put a plunger out (very loud).
Can you hear where the leak is coming from - may be a hiss. The other option is your pump is bust.
see if there are any tips in this link (https://community.preproom.org/inde...tter-results-without-spending-a-fortune.4735/)
 

clairelucas

COMMITTEE
If you put thin washing up liquid round the possible leaky places, may get obvious bubbles where leaking.
Great minds re personal alarm- our bell 'dropped off' its clips, so i suggested the same while fixing- also had the advantage of being able to be put in a vacuum thermos flask, though haven't tested the theory as a) loud and b) not needed in the end...
Worrying that your javac pumps haven't needed re-oiling, ours hadn't been used in ages, and appeared empty. I've rechecked it, and still where it should be after a few days, but could possibly mean there is a slow leak? No evidence of leakage though in box, so hopefully not...
 
we dont use a bell anymore, a buzzer and 1.5v battery does the job just fine, we have it sat on a bit of foam to stop any vibrations transmitting.
 
buzzer and a led so the led stays lit, So no cleaver clogs says ohh they have turned off the BUZZZZZ
 

Peter Sigsworth

COMMITTEE
buzzer and a led so the led stays lit, So no cleaver clogs says ohh they have turned off the BUZZZZZ
You don't need to do that as if you seal the jar by turning the valve to off and disconnect the pump completely. There is still silence and as you open the valve, they can hear the hiss as the air goes back in and then the sound of the buzzer/bell can be heard - it even gets louder as more air enters the jar.
 
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