Bimetalic domes
 

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?

Bimetalic domes
 

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" wrote in message ...
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?

Bimetalic domes
 

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.

Bimetalic domes
 

Steve Lusardi wrote in message
...
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" wrote in message
...
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

Bimetalic domes
 

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.

Bimetalic domes
 

William Sommerwerck wrote in message
...
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

Bimetalic domes
 

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.

Bimetalic domes
 

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.

Bimetalic domes
 

On Sun, 8 Nov 2009 08:42:26 -0000, "N_Cook" 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
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Bimetalic domes
 

On Sun, 8 Nov 2009 08:42:26 -0000, "N_Cook" 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."

Bimetalic domes
 

On Sun, 8 Nov 2009 08:42:26 -0000, "N_Cook" 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.

Bimetalic domes
 

Baron wrote:

On Sun, 8 Nov 2009 08:42:26 -0000, "N_Cook" 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!

Bimetalic domes
 

Michael A. Terrell wrote:


Baron wrote:

On Sun, 8 Nov 2009 08:42:26 -0000, "N_Cook"
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.

Bimetalic domes
 

On Sun, 8 Nov 2009 17:37:59 -0000, "N_Cook" wrote:

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

Probably by electroplating one of the meterials onto the other.


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

Bimetalic domes
 

Baron wrote:

Michael A. Terrell wrote:


Baron wrote:

On Sun, 8 Nov 2009 08:42:26 -0000, "N_Cook"
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!

Bimetalic domes
 

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.

Bimetalic domes
 

Martin H. Eastburn wrote in message
...
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

Bimetalic domes
 

On Nov 8, 6:56*pm, "Martin H. Eastburn"
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.

Bimetalic domes
 

whit3rd wrote:

On Nov 8, 6:56Â*pm, "Martin H. Eastburn"
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.

Bimetalic domes
 

William Wixon wrote in message
...

"Baron" wrote in message
...
whit3rd wrote:

On Nov 8, 6:56 pm, "Martin H. Eastburn"
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

Bimetalic domes
 

Mark Rand wrote in message
...
On Mon, 9 Nov 2009 16:13:19 -0600, "William Wixon"

wrote:




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.


If there were room, one could add a preload spring to change the set
point.

Mark Rand
RTFM

I might try that , will require adding a small well for the spring

Bimetalic domes
 

N_Cook 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 wonder if one could paint the convex face with fingernail polish as
an etch resist and put the disc in an etching solution to thin the
concave side? Would the relatively smaller 'concave mass' shift the
trigger temperature upwards?

--Winston

--

On YouTube, all the tools have volume controls.

Bimetalic domes
 

As used in thermal switches. Instead of in form of a bimetal strip
and continuous curving with temperature, these are 0.5" 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?

Heaven knows, I don't like reinventing the wheel, but unless you can find
documentation (such as a patent) that explains in detail how these devices
work, and how a particular temperature is set, you're going to have to
experiment.

I again recommend looking for one of those interchangeable thermostats.
Perhaps ripping it apart will reveal the secret!

http://www.gopresto.com/products/pro...hp?stock=07211

http://www.acehardwareoutlet.com/(ua...?SKU=998000074

http://www.advertisingcookbooks.com/si/004123.html

The Presto "Control Master" has been around at least 40 years, and Presto is
still making appliances that use it. (I don't know whether the internal
design or operating principles have changed. The probe part does appear to
be longer and narrower in the current version.)

Bimetalic domes
 

On Nov 8, 8:42*am, "N_Cook" 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 have been waiting for someone to suggest that the temperature at
which they switch is controlled by how domed the discs are. At least
that is my guess. Suggest you get some rubber and a ballpein hammer.
Test what the temperature is that one switches at, and then make in a
bit more domed and see if that changed the temperature at which it
switches. My guess is that more domed means more change from ambient
temperature before it switches.

Dan

Bimetalic domes
 

wrote in message
...
On Nov 8, 8:42 am, "N_Cook" 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 have been waiting for someone to suggest that the temperature at
which they switch is controlled by how domed the discs are. At least
that is my guess. Suggest you get some rubber and a ballpein hammer.
Test what the temperature is that one switches at, and then make in a
bit more domed and see if that changed the temperature at which it
switches. My guess is that more domed means more change from ambient
temperature before it switches.

Dan

I will give it a go with large ballbearing in a cup and a press. But the
full range of temp (10 to 220 deg C at least) switches all come in the same
size package and the internal spaces and activation pins are the same
dimensions including degree of doming, all that changes is the materials or
construction within the domes. Normally open for the same temp normally
closed is simply just the same dome in, the other way up

Bimetalic domes
 

On Wed, 11 Nov 2009 08:49:44 -0000, "N_Cook"
wrote:

wrote in message
.. My guess is that more domed means more change from ambient
temperature before it switches.

Dan

I will give it a go with large ballbearing in a cup and a press.

Another thing to try is local heating and quenching in order to change
the distribution of internal stresses in the dome.

--
Ned Simmons

Bimetalic domes
 

In article ,
Ned Simmons wrote:

On Wed, 11 Nov 2009 08:49:44 -0000, "N_Cook"
wrote:

wrote in message
. My guess is that more domed means more change from ambient
temperature before it switches.

Dan

I will give it a go with large ballbearing in a cup and a press.

Another thing to try is local heating and quenching in order to change
the distribution of internal stresses in the dome.

It's bimetal; I don't think you want any "unexpected" stresses.

Isaac

Bimetalic domes
 

--Messed around with these ages ago. The delta-T for the flip is
inversely proportional to the radius of curvature; i.e. greater radius
translates to smaller temp changes to make it flip. I was working on what I
call a 'kinetic solar cell' which works very well in theory...

--
"Steamboat Ed" Haas : Currently broke and
Hacking the Trailing Edge! : looking for a job...
www.nmpproducts.com
---Decks a-wash in a sea of words---