Jada Ahern on sun 9 jan 00
------------------
Hi...
Looking for helpful hints on mounting and using an analog pyrometer.
I was given a brand new one for Xmas. It has a 12in thermocouple and is =
made
by Cress. Does it need a battery? Do I attach the wires from the meter to =
the
wires for the thermocouple? Should I mount the display meter to something?
I would like to be able to use it mostly for my Flat Top Gas Kiln (two =
peeps,
two burner ports). I also have a Raku kiln I would like to use it in when I
don't have the white crackle in there to check for temperature.
I had never even see a pyrometer, let alone used one, so any advise on how =
to
use it would be great too. (Like what hole and how far into the kiln?)
I also have some questions about the big Flat Top.. While firing, and in
reduction, the =22Dragons Tongue=22 licks back through the burner port and =
is very
hard on the area where the thermocouple sits. I have had problems with the
thermocouples melting down or failing... is this normal? I have many =
more
questions, but that is good for a starter...
Thank you in advance=21=21
Jada Ahern jadaca=40uswest.net
Manager-Hummingbird House Studios
Bed and Breakfast =26 Potters Retreat
Tucson, AZ
GSM_ENT on mon 10 jan 00
Hi Jada!
Happy New Year!!!
Pyrometers come in two fashion: analogs (with a dial and an indicator
needle) and digitals (with a window to display the numbers).
Your analog pyrmeter consists of three basic parts: a "box" with the dial, a
pair of lead wires made out of two wires, and the thermocouple.
The thermocouple itself in fact is made out of two different alloy wires
where one is magnetic and are welded at one end; the one that goes into the
kiln. When these thermocouple wires register changes of temperature, they
create a minute voltage which is registered at the dial of the pyrometer and
is shown as a change in temperature.
The pyrometers and thermocouples use NO batteries. To install it you just
insert the thermocouple into the firing chamber through a hole in the kiln.
Some kilns come with a small hole on the side of the metal jacket. Your can
see the firebrick through it as the manufacturer does not make the hole on
the brick unless the kiln is ordered with a thermocouple. Since the
firebrick is so soft you can bore the hole through the firebrick to insert
the thermocouple. The hole should be slightly larger that the diameterof the
thermocouple as to not lose heat from it.
If your pyrometer does not have the lead wires conneted you must do so
before using it. Simple connect the wires to two wires to the two screws on
the back of the pyrometer. If you connect them backwards when you apply some
temperature increase (like with a match) to the end of the thermocouple, the
temperature will drop instead of rise. Then just disconect the two wires and
reverse them.
There are also peephole plugs specially designed for thermocouples. They
have a hole in the center through which you can insert the thermocouple.
Before you fire you should insert the thermocouple through whichever hole
you intend to use and measure it so that it does not extend past 3/4 to 5/8
of an inch inside the firing chamber. Then, with a marker, on the outside of
the kiln, mark the thermocouple so that you can always insert it just to the
right depth. Some people used a small piece of wire to mark it outside.
The pyrometer (box) containing the dial has on its back a hole which you can
use to hand it from the wall. Normaly the lead wire is fairly long to allow
you to do this. Do not hang it to the kiln jacket.
The dial has a small screw head showing in the apex of the needle of the
pyrometer. This is an adjusting screw to calibrate it. Pyrometers must be
calibrated before actual ware firing is made. The needle should read room
temperature. If it does not use a small 1/8 inch flat tip screw driver and
GENTLY move the needle to match the reading on the scale. do a test firing
using a pyrometric witness cone.
Get a small mirror so that you can watch the cone inside the firing chamber
without looking directly into the kiln. When the kin is on high it yields
infra red and ultra violet rays plus the high heat cand also be dangerous.
Know the temperature equivalent of the firing cone you want to fire to.
Watch the witness cone inside the firing chamber. When the witness cone
bends to a 6 o'clock position check the pyrometer needle, if it is not
pointing to the temperature equivalence of the cone use the screwdriver and
adjust it. Once this is done you can use the thermocouple and be fairly
close to the cone value.
I teach the Orton Firing Institute Firing Seminar and have some extra
handouts. If you would like a packet of additional information from the
Orton Foundation on firing, or on how to calibrate your kiln sitter or
controller board on your computerized kiln, please contact me at my private
E-Mail: GSM_ENT@MSN.COM.
Regard,
Manuel R A "Tony" Diaz Rodriguez
MAJ., US Army (Ret.)
Master Kiln Repair technician
Owner-GSM Enterprises
.
----- Original Message -----
From: Jada Ahern
To:
Sent: Sunday, January 09, 2000 8:47 AM
Subject: Pyrometer Installation (analog)
----------------------------Original message----------------------------
------------------
Hi...
Looking for helpful hints on mounting and using an analog pyrometer.
I was given a brand new one for Xmas. It has a 12in thermocouple and is
made
by Cress. Does it need a battery? Do I attach the wires from the meter to
the
wires for the thermocouple? Should I mount the display meter to something?
I would like to be able to use it mostly for my Flat Top Gas Kiln (two
peeps,
two burner ports). I also have a Raku kiln I would like to use it in when I
don't have the white crackle in there to check for temperature.
I had never even see a pyrometer, let alone used one, so any advise on how
to
use it would be great too. (Like what hole and how far into the kiln?)
I also have some questions about the big Flat Top.. While firing, and in
reduction, the "Dragons Tongue" licks back through the burner port and is
very
hard on the area where the thermocouple sits. I have had problems with the
thermocouples melting down or failing... is this normal? I have many
more
questions, but that is good for a starter...
Thank you in advance!!
Jada Ahern jadaca@uswest.net
Manager-Hummingbird House Studios
Bed and Breakfast & Potters Retreat
Tucson, AZ
Veronica Honthaas on tue 11 jan 00
What is the reason for only inserting the thermocoupler 5/8 of an inch
inside the kiln? Veronica
At 04:10 PM 1/10/00 EST, you wrote:
>----------------------------Original message----------------------------
>Hi Jada!
>
>Happy New Year!!!
>
>Pyrometers come in two fashion: analogs (with a dial and an indicator
>needle) and digitals (with a window to display the numbers).
>
>Your analog pyrmeter consists of three basic parts: a "box" with the dial, a
>pair of lead wires made out of two wires, and the thermocouple.
>
>The thermocouple itself in fact is made out of two different alloy wires
>where one is magnetic and are welded at one end; the one that goes into the
>kiln. When these thermocouple wires register changes of temperature, they
>create a minute voltage which is registered at the dial of the pyrometer and
>is shown as a change in temperature.
>
>The pyrometers and thermocouples use NO batteries. To install it you just
>insert the thermocouple into the firing chamber through a hole in the kiln.
>Some kilns come with a small hole on the side of the metal jacket. Your can
>see the firebrick through it as the manufacturer does not make the hole on
>the brick unless the kiln is ordered with a thermocouple. Since the
>firebrick is so soft you can bore the hole through the firebrick to insert
>the thermocouple. The hole should be slightly larger that the diameterof the
>thermocouple as to not lose heat from it.
>
>If your pyrometer does not have the lead wires conneted you must do so
>before using it. Simple connect the wires to two wires to the two screws on
>the back of the pyrometer. If you connect them backwards when you apply some
>temperature increase (like with a match) to the end of the thermocouple, the
>temperature will drop instead of rise. Then just disconect the two wires and
>reverse them.
>
>There are also peephole plugs specially designed for thermocouples. They
>have a hole in the center through which you can insert the thermocouple.
>Before you fire you should insert the thermocouple through whichever hole
>you intend to use and measure it so that it does not extend past 3/4 to 5/8
>of an inch inside the firing chamber. Then, with a marker, on the outside of
>the kiln, mark the thermocouple so that you can always insert it just to the
>right depth. Some people used a small piece of wire to mark it outside.
>
>The pyrometer (box) containing the dial has on its back a hole which you can
>use to hand it from the wall. Normaly the lead wire is fairly long to allow
>you to do this. Do not hang it to the kiln jacket.
>
>The dial has a small screw head showing in the apex of the needle of the
>pyrometer. This is an adjusting screw to calibrate it. Pyrometers must be
>calibrated before actual ware firing is made. The needle should read room
>temperature. If it does not use a small 1/8 inch flat tip screw driver and
>GENTLY move the needle to match the reading on the scale. do a test firing
>using a pyrometric witness cone.
>
>Get a small mirror so that you can watch the cone inside the firing chamber
>without looking directly into the kiln. When the kin is on high it yields
>infra red and ultra violet rays plus the high heat cand also be dangerous.
>Know the temperature equivalent of the firing cone you want to fire to.
>Watch the witness cone inside the firing chamber. When the witness cone
>bends to a 6 o'clock position check the pyrometer needle, if it is not
>pointing to the temperature equivalence of the cone use the screwdriver and
>adjust it. Once this is done you can use the thermocouple and be fairly
>close to the cone value.
>
>I teach the Orton Firing Institute Firing Seminar and have some extra
>handouts. If you would like a packet of additional information from the
>Orton Foundation on firing, or on how to calibrate your kiln sitter or
>controller board on your computerized kiln, please contact me at my private
>E-Mail: GSM_ENT@MSN.COM.
>
>
>Regard,
>
>Manuel R A "Tony" Diaz Rodriguez
>MAJ., US Army (Ret.)
>Master Kiln Repair technician
>Owner-GSM Enterprises
>.
>
>
>----- Original Message -----
>From: Jada Ahern
>To:
>Sent: Sunday, January 09, 2000 8:47 AM
>Subject: Pyrometer Installation (analog)
>
>
>----------------------------Original message----------------------------
>------------------
>Hi...
>
>Looking for helpful hints on mounting and using an analog pyrometer.
>
>I was given a brand new one for Xmas. It has a 12in thermocouple and is
>made
>by Cress. Does it need a battery? Do I attach the wires from the meter to
>the
>wires for the thermocouple? Should I mount the display meter to something?
>
>
>I would like to be able to use it mostly for my Flat Top Gas Kiln (two
>peeps,
>two burner ports). I also have a Raku kiln I would like to use it in when I
>don't have the white crackle in there to check for temperature.
>
>I had never even see a pyrometer, let alone used one, so any advise on how
>to
>use it would be great too. (Like what hole and how far into the kiln?)
>
>
>I also have some questions about the big Flat Top.. While firing, and in
>reduction, the "Dragons Tongue" licks back through the burner port and is
>very
>hard on the area where the thermocouple sits. I have had problems with the
>thermocouples melting down or failing... is this normal? I have many
>more
>questions, but that is good for a starter...
>
>Thank you in advance!!
>
>Jada Ahern jadaca@uswest.net
>Manager-Hummingbird House Studios
>Bed and Breakfast & Potters Retreat
>Tucson, AZ
>
>
ferenc jakab on tue 11 jan 00
Just a note of warning on pyrometers. I don't know of a single type of
pyrometer that can read accurately over 1000 deg C. There may be individual
ones that perform this miracle but generally they don't. ALWAYS USE CONES
OVER 1000 deg C.
Feri.
Hank Murrow on wed 12 jan 00
>----------------------------Original message----------------------------
>Just a note of warning on pyrometers. I don't know of a single type of
>pyrometer that can read accurately over 1000 deg C. There may be individual
>ones that perform this miracle but generally they don't. ALWAYS USE CONES
>OVER 1000 deg C.
>Feri.
Dear Feri; Have you tried a Platinum/Rhodium thermocouple? I always use
Cones 9,10, & 11 for decciding when to turn the kiln off; but have found
that my OxyProbe Platinum/Rhodium thermocouple has great correspondence
with the cones. Of course, no thermocouple can measure actual heat work,
which is the effects of Time AND Temperature. Regards, Hank in Eugene
David Woodin on wed 12 jan 00
A thermocouple reads temperature at the tip and to get a good reading you
need the proper insertion depth. One mfg suggests 6 to 8 times the O.D. of
the protecting tube and the junction where the extension wires are attached
kept below 400 deg F. Too little insertion dept gives low readings.
David
David Woodin on wed 12 jan 00
That is not a true statement. Pyrometers measure temperature and very
accurately, cones measure heat work, the secret is to find out the
temperature at a certain rate of rise that will agree with a cone. The
tables are based on 108 deg F per hour rise for the last 1 1/2 to 2 hours and
anything different from that results in a different temperature as read by a
pyrometer. For example a rate of rise of 60 deg per hour for the last 1 1/2
to 2 hours will cause cone 9 to fall at very close to 2272 deg F. Whereas at
108 deg /hr a self supporting cone falls at 2300 deg F and a regular cone at
2295 deg F. The Orton cone tables that should be used are dated 1996.
David
ferenc jakab on thu 13 jan 00
Hank I have not used Platinum Rhodium, Mine are Platinum Niobium (I think).
Yes its the 'heat work' which is truly important and all the ceramicists I
know always use cones as the final guide too. I'm probably a little out of
touch with recent improvements in pyrometer technology, I'm aware of these
new cheaper oxyprobe/pyrometers but have not seen one operating. I've
considered purchasing one but I'm not sure that I wish to miss out on the
fun of judging the state of the flame and clarity of atmosphere etc. I
refused automated and blower boosted burners for the same reason. I know,
I'm a recidivist, but I really enjoy flying by the seat of my pants.
Feri.
GSM_ENT on thu 13 jan 00
Hi Veronica!
The thermocouple only reads the temperature through the tip. Excess portion
inside the kiln only increases the chances to have it broken with a shelf
while loading. If it is too close to the wall it will give an erroneous
reading as the heating coils are in the wall. On its design the average
thermocouple readings were made between 5/8 and 1 inch from the kiln wall.
Regarda,
Manuel R A "Tony" Diaz Rodriguez
MAJ., US Army (Ret)
Master Kiln Repair Technician
----- Original Message -----
From: Veronica Honthaas
To:
Sent: Tuesday, January 11, 2000 7:57 AM
Subject: Re: Pyrometer Installation (analog)
> ----------------------------Original message----------------------------
>
>
> What is the reason for only inserting the thermocoupler 5/8 of an inch
> inside the kiln? Veronica
>
>
> At 04:10 PM 1/10/00 EST, you wrote:
> >----------------------------Original message----------------------------
> >Hi Jada!
> >
> >Happy New Year!!!
> >
> >Pyrometers come in two fashion: analogs (with a dial and an indicator
> >needle) and digitals (with a window to display the numbers).
> >
> >Your analog pyrmeter consists of three basic parts: a "box" with the
dial, a
> >pair of lead wires made out of two wires, and the thermocouple.
> >
> >The thermocouple itself in fact is made out of two different alloy wires
> >where one is magnetic and are welded at one end; the one that goes into
the
> >kiln. When these thermocouple wires register changes of temperature, they
> >create a minute voltage which is registered at the dial of the pyrometer
and
> >is shown as a change in temperature.
> >
> >The pyrometers and thermocouples use NO batteries. To install it you just
> >insert the thermocouple into the firing chamber through a hole in the
kiln.
> >Some kilns come with a small hole on the side of the metal jacket. Your
can
> >see the firebrick through it as the manufacturer does not make the hole
on
> >the brick unless the kiln is ordered with a thermocouple. Since the
> >firebrick is so soft you can bore the hole through the firebrick to
insert
> >the thermocouple. The hole should be slightly larger that the diameterof
the
> >thermocouple as to not lose heat from it.
> >
> >If your pyrometer does not have the lead wires conneted you must do so
> >before using it. Simple connect the wires to two wires to the two screws
on
> >the back of the pyrometer. If you connect them backwards when you apply
some
> >temperature increase (like with a match) to the end of the thermocouple,
the
> >temperature will drop instead of rise. Then just disconect the two wires
and
> >reverse them.
> >
> >There are also peephole plugs specially designed for thermocouples. They
> >have a hole in the center through which you can insert the thermocouple.
> >Before you fire you should insert the thermocouple through whichever hole
> >you intend to use and measure it so that it does not extend past 3/4 to
5/8
> >of an inch inside the firing chamber. Then, with a marker, on the outside
of
> >the kiln, mark the thermocouple so that you can always insert it just to
the
> >right depth. Some people used a small piece of wire to mark it outside.
> >
> >The pyrometer (box) containing the dial has on its back a hole which you
can
> >use to hand it from the wall. Normaly the lead wire is fairly long to
allow
> >you to do this. Do not hang it to the kiln jacket.
> >
> >The dial has a small screw head showing in the apex of the needle of the
> >pyrometer. This is an adjusting screw to calibrate it. Pyrometers must be
> >calibrated before actual ware firing is made. The needle should read room
> >temperature. If it does not use a small 1/8 inch flat tip screw driver
and
> >GENTLY move the needle to match the reading on the scale. do a test
firing
> >using a pyrometric witness cone.
> >
> >Get a small mirror so that you can watch the cone inside the firing
chamber
> >without looking directly into the kiln. When the kin is on high it yields
> >infra red and ultra violet rays plus the high heat cand also be
dangerous.
> >Know the temperature equivalent of the firing cone you want to fire to.
> >Watch the witness cone inside the firing chamber. When the witness cone
> >bends to a 6 o'clock position check the pyrometer needle, if it is not
> >pointing to the temperature equivalence of the cone use the screwdriver
and
> >adjust it. Once this is done you can use the thermocouple and be fairly
> >close to the cone value.
> >
> >I teach the Orton Firing Institute Firing Seminar and have some extra
> >handouts. If you would like a packet of additional information from the
> >Orton Foundation on firing, or on how to calibrate your kiln sitter or
> >controller board on your computerized kiln, please contact me at my
private
> >E-Mail: GSM_ENT@MSN.COM.
> >
> >
> >Regard,
> >
> >Manuel R A "Tony" Diaz Rodriguez
> >MAJ., US Army (Ret.)
> >Master Kiln Repair technician
> >Owner-GSM Enterprises
> >.
> >
> >
> >----- Original Message -----
> >From: Jada Ahern
> >To:
> >Sent: Sunday, January 09, 2000 8:47 AM
> >Subject: Pyrometer Installation (analog)
> >
> >
> >----------------------------Original message----------------------------
> >------------------
> >Hi...
> >
> >Looking for helpful hints on mounting and using an analog pyrometer.
> >
> >I was given a brand new one for Xmas. It has a 12in thermocouple and is
> >made
> >by Cress. Does it need a battery? Do I attach the wires from the meter
to
> >the
> >wires for the thermocouple? Should I mount the display meter to
something?
> >
> >
> >I would like to be able to use it mostly for my Flat Top Gas Kiln (two
> >peeps,
> >two burner ports). I also have a Raku kiln I would like to use it in
when I
> >don't have the white crackle in there to check for temperature.
> >
> >I had never even see a pyrometer, let alone used one, so any advise on
how
> >to
> >use it would be great too. (Like what hole and how far into the kiln?)
> >
> >
> >I also have some questions about the big Flat Top.. While firing, and
in
> >reduction, the "Dragons Tongue" licks back through the burner port and is
> >very
> >hard on the area where the thermocouple sits. I have had problems with
the
> >thermocouples melting down or failing... is this normal? I have
many
> >more
> >questions, but that is good for a starter...
> >
> >Thank you in advance!!
> >
> >Jada Ahern jadaca@uswest.net
> >Manager-Hummingbird House Studios
> >Bed and Breakfast & Potters Retreat
> >Tucson, AZ
> >
> >
GSM_ENT on thu 13 jan 00
Hi David!
Happy New Year!!!!!
You are totally correct in stating that pyrometers measure temperature and
cones heat work. Heat work defined as the exposure of the ware to the
combination of time and temperature (including heat rise as a factor).
However, if the pyrometer is not properly calibrated the readings will be
skewed.
As a general rule you can come very close by "calibrating" the pyrometer as
stated before as long as you always use the same firing schedule (x minutes
on low, x minutes on medium, and then on high until reaching temperature
desired). It is very difficult to explain a just a few words the workings or
factors involved in the firing to maturity of ware in just a few words.
The Temperature Equivalents for Orton Pyrometric Cones tables (containing
both F and C values) were in fact published in 1996 (October 28, 1996) and
as stated on the top they are only a guide. The actual bending temperature
depends on firing conditions.
The table depicts the three basic type cones: self-supporting, large and
small (firing cones). The first two columns are further divided into regular
and iron free type cones. The iron free type are mostly used in pottery, In
typical earthenware firing we normaly use the rgular cones (mostly "low
fired" casted ceramics where iron, sulphur, etc., contamination of colors is
of no concern. Most "low fire" ceramicists do not even know that these
exists.
The regular and iron free columns are further subdivided into 4 firing
heating rates: 27, 108, 270 and 540 (on the Fahrenheit side), this last one
only applies to small cones. The C side shows the same rates but in their
equivalent values in Celcius (15, 60, 150 and 300 degrees C).
The 108 degrees F have been used as the standard on controller boards of
computerized kilns. This provided for a "brake" so that the kiln does not
over-pass the desires temperature to be reached at the end of the firing.
Since what we actually do is nothing more than a physics experiment to
achieve repeated results (hopufully successful ones) if you control most of
the elements involved on the experiment we have better chance to suceed. By
repeating the firing using the same firing schedule for the same type
materials we should be able to achieve this. If all other elements are the
same and with a properly calibrated thermocouple we should be able to have
successful firings just be firing for the same amount of time or up to the
temperature required to bend the cone.
It is very refreshing to see that there is interest out there in maintaining
ourselves up to date in the latest information available. No one can
actually be up to date on all the aspects of the industy. Thank you very
much for your information. I look forward to see more of input on posted
topics from your part as well as others in the group.
Happy firing.
Manuel R A "Tony" Diaz Rodriguez
MAJ., US Army (Ret.)
Master Kiln Repair Technician
Multi-Company Qualified
----- Original Message -----
From: David Woodin
To:
Sent: Wednesday, January 12, 2000 2:47 PM
Subject: Re: Pyrometer Installation (analog)
> ----------------------------Original message----------------------------
> That is not a true statement. Pyrometers measure temperature and very
> accurately, cones measure heat work, the secret is to find out the
> temperature at a certain rate of rise that will agree with a cone. The
> tables are based on 108 deg F per hour rise for the last 1 1/2 to 2 hours
and
> anything different from that results in a different temperature as read by
a
> pyrometer. For example a rate of rise of 60 deg per hour for the last 1
1/2
> to 2 hours will cause cone 9 to fall at very close to 2272 deg F. Whereas
at
> 108 deg /hr a self supporting cone falls at 2300 deg F and a regular cone
at
> 2295 deg F. The Orton cone tables that should be used are dated 1996.
> David
Hank Murrow on fri 14 jan 00
>----------------------------Original message----------------------------
>Hank I have not used Platinum Rhodium, Mine are Platinum Niobium (I think).
>Yes its the 'heat work' which is truly important and all the ceramicists I
>know always use cones as the final guide too. I'm probably a little out of
>touch with recent improvements in pyrometer technology, I'm aware of these
>new cheaper oxyprobe/pyrometers but have not seen one operating. I've
>considered purchasing one but I'm not sure that I wish to miss out on the
>fun of judging the state of the flame and clarity of atmosphere etc. I
>refused automated and blower boosted burners for the same reason. I know,
>I'm a recidivist, but I really enjoy flying by the seat of my pants.
>Feri.
Hi Feri; I think of the OxyProbe (around $600) as a kind of strange
potter-friend who can look in the kiln and see stuff that is invisible to
me. Everything is OK if I don't let him do my fires; and I just consult him
from time to time. My 27 CuFt Doorless Fiber Kiln runs off one 2" Eclipse
atmospheric mixer; and is a dream to fire, seated or flying. Send you a pic
if you send me your e-mail. Bon Cuisson! Hank in Eugene
ferenc jakab on fri 14 jan 00
Manuel, what you say has a certain logic for electric kilns but any kiln
fired by some sort of flame is also affected by things such as wind velocity
causing increased draw in the flue and humidity, especially for gas kilns
where the combustion of gas gives off water.
Feri.
GSM_ENT on sun 16 jan 00
Hi Feri:
Happy New Year!!!!
When an answer is posted it most be taken as a grain of salt. There should
be additional in depth research on the subject at hand. I have always
thought that the board was intended to provide guidelines and not a quick
fix answer.
Firing, as stated previously, is just a repeated simple physics experiment
were we "attempt" to control all variables. If we were at the laboratory we
would be much more careful and specific. this would include taking the
weigth of the ware and kiln furniture (mass) to be fired to make use of
mathematical computations to find out the amount of time and the
temperature needed in order to mature the ware.
Warm Regards,
MANUEL R A "TONY" DIAZ RODRIGUEZ
MAJ., US Army (Ret)
Master Kiln Repair Technician
----- Original Message -----
From: ferenc jakab
To:
Sent: Friday, January 14, 2000 1:39 PM
Subject: Re: Pyrometer Installation (analog)
> ----------------------------Original message----------------------------
> Manuel, what you say has a certain logic for electric kilns but any kiln
> fired by some sort of flame is also affected by things such as wind
velocity
> causing increased draw in the flue and humidity, especially for gas kilns
> where the combustion of gas gives off water.
> Feri.
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