Bimetalic domes

[N_Cook]

As used in thermal switches. Instead of in form of a bimetal strip and
continuous curving with temperature, these are 0.5 inch diameter and make a
definite flip from concave to convex at a specific temperature. About 1mm of
abrupt movement gives a very positive transition for the switch contacts.
Would it be possible to change the characteristic temperature by grinding
back a spot/ring/radii? on one face? which face? or would it just destroy
the action/activation force?

 

[Steve Lusardi]

Sure you can do this, but get a few of these, as the odds of getting it right the 1st time is slim.
Steve

"N_Cook" <diverse@tcp.co.uk> wrote in message news:hd608l$u0r$1@news.eternal-september.org...

As used in thermal switches. Instead of in form of a bimetal strip and
continuous curving with temperature, these are 0.5 inch diameter and make a
definite flip from concave to convex at a specific temperature. About 1mm of
abrupt movement gives a very positive transition for the switch contacts.
Would it be possible to change the characteristic temperature by grinding
back a spot/ring/radii? on one face? which face? or would it just destroy
the action/activation force?

 

[William Sommerwerck]

How important is the overall size of the sensor?

You might find one of the sort that used to be used in kitchen appliances,
that could be inserted in a grill, waffle maker, cookpot, etc. These have
adjustable settings, which (I assume) are varied by changing the pressure on
the sensor.

 

[N_Cook]

Steve Lusardi <stevenospam@lusardi.de> wrote in message
news:hd683k$jvj$00$1@news.t-online.com...

Sure you can do this, but get a few of these, as the odds of getting it
right the 1st time is slim.
Steve

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:hd608l$u0r$1@news.eternal-september.org...
As used in thermal switches. Instead of in form of a bimetal strip and
continuous curving with temperature, these are 0.5 inch diameter and
make a
definite flip from concave to convex at a specific temperature. About
1mm of
abrupt movement gives a very positive transition for the switch
contacts.
Would it be possible to change the characteristic temperature by
grinding
back a spot/ring/radii? on one face? which face? or would it just
destroy
the action/activation force?

According to patent
"Laser adjusted set-point of bimetallic thermal disc"
it is done at production , for precise adjustment, but no specific details
of patterns/which surface/degree of variation. I'm more interested in
adjusting otherwise useless batch made for set point of 16 degree C up to
50 or 60 degree C, with no great precision, +/- 10 deg C would be fine

 

[William Sommerwerck]

According to patent
"Laser adjusted set-point of bimetallic thermal disc"
it is done at production , for precise adjustment, but no specific details
of patterns/which surface/degree of variation. I'm more interested in
adjusting otherwise useless batch made for set point of 16 degree C up to
50 or 60 degree C, with no great precision, +/- 10 deg C would be fine

If you could find the patent for the controller I described (it's a famous
patent, from a man who patented many devices in the 50s and 60s), it might
show how this is done.

 

[N_Cook]

William Sommerwerck <grizzledgeezer@comcast.net> wrote in message
news:hd6ik6$eip$1@news.eternal-september.org...

According to patent
"Laser adjusted set-point of bimetallic thermal disc"
it is done at production , for precise adjustment, but no specific
details
of patterns/which surface/degree of variation. I'm more interested in
adjusting otherwise useless batch made for set point of 16 degree C up
to
50 or 60 degree C, with no great precision, +/- 10 deg C would be fine

If you could find the patent for the controller I described (it's a famous
patent, from a man who patented many devices in the 50s and 60s), it might
show how this is done.

probably a John Taylor
http://content.yudu.com/A15ex7/Apro9/resources/8.htm
but no further forward, I'll suck some and see

 

[William Sommerwerck]

probably a John Taylor
http://content.yudu.com/A15ex7/Apro9/resources/8.htm

I'm not sure. The guy I'm thinking of is American.

 

[N_Cook]

Interesting , but no further forward. Looks as though these froststats will
remain froststats. Surprising ping and bounce as much as six inches on
change of state, the loud ping is somewhat damped when inside the casing.
Need freezer spray to change the state of these discs (hysteresis and all
that). When back to body temp I tried grinding a spot in the centre of the
concave side, no change in set temp. Tried 4 diametrical marks on the
concave side , no change in response. Tried deeper but small 8 cuts just on
the perphery, now no ping but slowly migrates from one state to the other ,
still requiring freezer spray. I wonder how they "weld" these 2 materials
together.

 

[Jeff Liebermann]

On Sun, 8 Nov 2009 08:42:26 -0000, "N_Cook" <diverse@tcp.co.uk> wrote:

As used in thermal switches. Instead of in form of a bimetal strip and
continuous curving with temperature, these are 0.5 inch diameter and make a
definite flip from concave to convex at a specific temperature. About 1mm of
abrupt movement gives a very positive transition for the switch contacts.

Like this?
<http://www.google.com/patents/about?id=VQ4XAAAAEBAJ&dq=5903210>
or this?
<http://www.google.com/patents/about?id=BygyAAAAEBAJ&dq=3852697>

Would it be possible to change the characteristic temperature by grinding
back a spot/ring/radii? on one face? which face? or would it just destroy
the action/activation force?

I don't think so (but I'm guessing). Grinding might change the
deflection or force but probably not the transition temperature. Below
some force level, it simply will not transition. My guess(tm) is that
the transition temperature is controlled by the curvature which is
rather difficult to modify.

Note that some discs are "manual reset" or "single operation" and act
as thermal fuses.

Search Google for "bimetallic snap disk".
<http://www.cpi-nj.com/snap.htm>
<http://www.thermodisc.com>
(etc...)
I tried to find the vendor of the actual discs, which might include
design information, but couldn't find anything useful.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Gunner Asch]

On Sun, 8 Nov 2009 08:42:26 -0000, "N_Cook" <diverse@tcp.co.uk> wrote:

As used in thermal switches. Instead of in form of a bimetal strip and
continuous curving with temperature, these are 0.5 inch diameter and make a
definite flip from concave to convex at a specific temperature. About 1mm of
abrupt movement gives a very positive transition for the switch contacts.
Would it be possible to change the characteristic temperature by grinding
back a spot/ring/radii? on one face? which face? or would it just destroy
the action/activation force?

Have you considered fire alarm heat sensors? They use a bimetal switch

internally.

Gunner

"IMHO, some people here give Jeff far more attention than he deserves,
but obviously craves. The most appropriate response, and perhaps the
cruelest, IMO, is to simply killfile and ignore him. An alternative, if
you must, would be to post the same standard reply to his every post,
listing the manifold reasons why he ought to be ignored. Just my $0.02
worth."

 

[Baron]

On Sun, 8 Nov 2009 08:42:26 -0000, "N_Cook" <diverse@tcp.co.uk> wrote:

As used in thermal switches. Instead of in form of a bimetal strip and
continuous curving with temperature, these are 0.5 inch diameter and
make a definite flip from concave to convex at a specific temperature.
About 1mm of abrupt movement gives a very positive transition for the
switch contacts. Would it be possible to change the characteristic
temperature by grinding back a spot/ring/radii? on one face? which
face? or would it just destroy the action/activation force?

I belive "Clixon" in the UK make these.

--
Best Regards:
Baron.

 

[Michael A. Terrell]

Baron wrote:

On Sun, 8 Nov 2009 08:42:26 -0000, "N_Cook" <diverse@tcp.co.uk> wrote:

As used in thermal switches. Instead of in form of a bimetal strip and
continuous curving with temperature, these are 0.5 inch diameter and
make a definite flip from concave to convex at a specific temperature.
About 1mm of abrupt movement gives a very positive transition for the
switch contacts. Would it be possible to change the characteristic
temperature by grinding back a spot/ring/radii? on one face? which
face? or would it just destroy the action/activation force?

I belive "Clixon" in the UK make these.

That is 'Klixon', which was a division of Texas Instruments.

Now it's a division of Sensata

<http://www.sensata.com/klixon/thermostats-thermostat.htm>


--
The movie 'Deliverance' isn't a documentary!

 

[Baron]

Michael A. Terrell wrote:

Baron wrote:

On Sun, 8 Nov 2009 08:42:26 -0000, "N_Cook" <diverse@tcp.co.uk
wrote:

As used in thermal switches. Instead of in form of a bimetal strip
and continuous curving with temperature, these are 0.5 inch diameter
and make a definite flip from concave to convex at a specific
temperature. About 1mm of abrupt movement gives a very positive
transition for the switch contacts. Would it be possible to change
the characteristic temperature by grinding back a spot/ring/radii?
on one face? which face? or would it just destroy the
action/activation force?

I belive "Clixon" in the UK make these.


That is 'Klixon', which was a division of Texas Instruments.

Now it's a division of Sensata

http://www.sensata.com/klixon/thermostats-thermostat.htm

Thanks for the spelling correction and link. Its a lot of years since I
played about with them. They were very popular in water heater
circuits at one time.

--
Best Regards:
Baron.

 

[Jeff Liebermann]

On Sun, 8 Nov 2009 17:37:59 -0000, "N_Cook" <diverse@tcp.co.uk> wrote:

I wonder how they "weld" these 2 materials
together.

Probably by electroplating one of the meterials onto the other.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Michael A. Terrell]

Baron wrote:

Michael A. Terrell wrote:


Baron wrote:

On Sun, 8 Nov 2009 08:42:26 -0000, "N_Cook" <diverse@tcp.co.uk
wrote:

As used in thermal switches. Instead of in form of a bimetal strip
and continuous curving with temperature, these are 0.5 inch diameter
and make a definite flip from concave to convex at a specific
temperature. About 1mm of abrupt movement gives a very positive
transition for the switch contacts. Would it be possible to change
the characteristic temperature by grinding back a spot/ring/radii?
on one face? which face? or would it just destroy the
action/activation force?

I belive "Clixon" in the UK make these.


That is 'Klixon', which was a division of Texas Instruments.

Now it's a division of Sensata

http://www.sensata.com/klixon/thermostats-thermostat.htm


Thanks for the spelling correction and link. Its a lot of years since I
played about with them. They were very popular in water heater
circuits at one time.

They still are, but a lot of their thermal motor starters are
discontinued.


--
The movie 'Deliverance' isn't a documentary!

 

[Martin H. Eastburn]

Explosive welding.
Simple as that.
Martin

N_Cook wrote:

Interesting , but no further forward. Looks as though these froststats will
remain froststats. Surprising ping and bounce as much as six inches on
change of state, the loud ping is somewhat damped when inside the casing.
Need freezer spray to change the state of these discs (hysteresis and all
that). When back to body temp I tried grinding a spot in the centre of the
concave side, no change in set temp. Tried 4 diametrical marks on the
concave side , no change in response. Tried deeper but small 8 cuts just on
the perphery, now no ping but slowly migrates from one state to the other ,
still requiring freezer spray. I wonder how they "weld" these 2 materials
together.

 

[N_Cook]

Martin H. Eastburn <lionslair@consolidated.net> wrote in message
news:mxLJm.189672$Jp1.32755@en-nntp-02.dc1.easynews.com...

Explosive welding.
Simple as that.
Martin

N_Cook wrote:
Interesting , but no further forward. Looks as though these froststats
will
remain froststats. Surprising ping and bounce as much as six inches on
change of state, the loud ping is somewhat damped when inside the
casing.
Need freezer spray to change the state of these discs (hysteresis and
all
that). When back to body temp I tried grinding a spot in the centre of
the
concave side, no change in set temp. Tried 4 diametrical marks on the
concave side , no change in response. Tried deeper but small 8 cuts just
on
the perphery, now no ping but slowly migrates from one state to the
other ,
still requiring freezer spray. I wonder how they "weld" these 2
materials
together.

I would have thought friction welding, probably many to a spin and then
press cut to small discs

 

[Baron]

whit3rd wrote:

On Nov 8, 6:56 pm, "Martin H. Eastburn" <lionsl...@consolidated.net
wrote:

N_Cook wrote:
I wonder how they "weld" these 2 materials
together.

Explosive welding.
Simple as that.

This might be the correct answer, but there are fill-metal/reducing
atmosphere/heat solutions that might do a kind of brazing for lower
cost
if you get the materials right. Explosive welding is used for US
coins
because it was possible to mimic the electromagnetic properties of
silver well enough to keep lots of vending machines in service.
I've gotta believe the requirements for a thermostat bimetal system
are loose enough to allow for alloys that don't require explosive
welds.

I was under the impression that two sheets of material were hot rolled
together and the discs just stamped out complete with the dome shape.

--
Best Regards:
Baron.

 

[whit3rd]

On Nov 8, 6:56 pm, "Martin H. Eastburn" <lionsl...@consolidated.net>
wrote:

N_Cook wrote:
I wonder how they "weld" these 2 materials
together.

Explosive welding.
Simple as that.

This might be the correct answer, but there are fill-metal/reducing
atmosphere/heat solutions that might do a kind of brazing for lower
cost
if you get the materials right. Explosive welding is used for US
coins
because it was possible to mimic the electromagnetic properties of
silver well enough to keep lots of vending machines in service.
I've gotta believe the requirements for a thermostat bimetal system
are loose enough to allow for alloys that don't require explosive
welds.

 

[N_Cook]

William Wixon <wwixon@frontiernet.net> wrote in message
news:MB%Jm.24082$Wd1.13423@newsfe15.iad...

"Baron" <baron.nospam@linuxmaniac.nospam.net> wrote in message
news:hd9vjc$bu7$1@news.eternal-september.org...
whit3rd wrote:

On Nov 8, 6:56 pm, "Martin H. Eastburn" <lionsl...@consolidated.net
wrote:

N_Cook wrote:
I wonder how they "weld" these 2 materials
together.

Explosive welding.
Simple as that.

This might be the correct answer, but there are fill-metal/reducing
atmosphere/heat solutions that might do a kind of brazing for lower
cost
if you get the materials right. Explosive welding is used for US
coins
because it was possible to mimic the electromagnetic properties of
silver well enough to keep lots of vending machines in service.
I've gotta believe the requirements for a thermostat bimetal system
are loose enough to allow for alloys that don't require explosive
welds.

I was under the impression that two sheets of material were hot rolled
together and the discs just stamped out complete with the dome shape.

--
Best Regards:
Baron.




how about instead of removing material from the flat surface of the dome
to
remove material around the outside diameter? would that alter the point
at
which the dome went PING? i was just wondering if the outside edge is
constrained in a bezel, if there was more room to expand there if that
would
alter it's temperature rating?

b.w.

The use I see them is located fairly loosely in a well in a bakelite disc
that is itself located loosely in the bakelite outer housing