This is great clarifying information.
Thanks, Hector!
Amilcar
>
> People that work in process control call (and draw in plant blueprints)
> thermometers as TI, TR, TIR and TRC (and TIRC).
>
> TI is any kind of temperature indicator that gives a point (current)
> indication of temperature; measurement could be based on different type of
> devices from thermocouples to Hg thermometers. Usually a TI is placed
> right
> in the action and the lecture is taken in the place of the action (e.g. at
> the CCP).
>
> TR are temperature recorders, and this could produce graphic records or be
> eventually coupled to a data logger and/ or to a computer. TR could be in
> remote positions, or positions not easily accessible, or positions that
> require of a continued monitoring. Lecture of that kind of temperatures is
> usually feasible from panels in the control room or from computer
> terminals.
>
> TIR are indicators/ recorders of temperature. This means they give a point
> lecture and produce a record (analogic or digital). This is the type of
> equipment that could appear coupled to a manual retort.
>
> TI, TR and TIR could have some additional functions like to make a ring
> bell
> when the temperature is above or below certain value. The purpose is
> obviously to assist in the manual control and avoid somebody should be
> sitting by the thermometer looking all the time.
>
> To make things a bit more complex in the physical word we have three
> different "temperatures", dry bulb, wet bulb and radiation temperature. In
> some type of processing (e.g. drying) we need indications of both the dry
> and
> the wet bulb temperatures. This is not a scientific speculation without
> practical interest. When we are putting a thermometer in a fresh fish, we
> are
> actually measuring the "wet bulb" temperature, that according to the
> relative
> humidity of the air around the fish, will be usually somewhat below the
> "dry
> bulb" temperature of the surrounding air. The net result is that the fish
> exposed to the air will star to dry, first of all in the surface, changing
> the environment of the fish natural flora and allowing for instance the
> development of contaminant flora. Ice not only keeps temperature low, it
> keeps fish wet.
>
> TRC are recorders/ controllers of temperature. This means the temperature
> is
> recorded (analogically or digitally) and the signal of temperature is
> utilized to control automatically the temperature in the case of deviation
> of
> the desired value. This is the type of device that can be found for
> instance
> in automatically controlled retorts, also in equipments like shrimp
> cookers.
> TIRC, the same but point lecture is possible on the spot too. The big
> difference between this type of equipment and the previous ones is that
> this
> type of equipment, more than "thermometers" are "temperature controllers".
> Whereas in all the cases the purpose of the measurement of temperature is
> to
> control it, in the case of non-C "thermometers" the control should be
> performed through an human operator.
>
> In the industry blueprints thermometers usually appear as a circle inside
> which appears the type, e.g. TIR and a code (place in the plant/ line,
> etc).
> Of course there are drawing standards for them, and also standards of how
> a
> TI should be (see for instance ASTM F2362-03
> http://webstore.ansi.org/ansidocstore/product.asp?sku=ASTM+F2362-03).
>
> Standards could vary somewhat from country to country. Good plants count
> with
> a blueprint were all the measurement devices are properly identified and
> located in the blueprint according with their actual position and purpose.
> The code is important because any measurement device should be calibrated
> periodically and therefore it should be possible to identify it properly
> in
> the plant (and in the calibration logbook). Probably this is the key point
> of
> all the discussion, thermometers should be calibrated, no matter the way
> they
> are indicating, recording or storing data; they are always utilized to
> control and/or monitoring.
>
> Finally it is true that technical documents and even documents that refer
> to
> regulations (or even in regulations) appear references to different type
> of
> thermometers (and way of reading and/ or recording) and this is not always
> clear. In new university curricula dealing with food (and fish) curricula
> there is now a subject on measurement and control under industrial
> conditions, however, this was not the case in the past.
>
> The knowledge on different type of measurement and recording equipment
> (not
> only for temperature) is becoming more and more important in the food and
> fish industry, since very often essential parts of the process are
> automatic
> (it means controlled automatically), for instance water chlorination today
> is
> done automatically practically all around the world, and manual retorts
> for
> canned food products are becoming a industrial museum item.
>
> Kind regards.
>
> Hector M. Lupin
> Consultant
> FAO of the UN
>
>
> -----Original Message-----
> From: owner-seafood@ucdavis.edu [mailto:owner-seafood@ucdavis.edu] On
> Behalf Of Dr. R. Viswanathan
> Sent: 27 July 2006 10:06
> To: Vinod V
> Cc: seafood@ucdavis.edu
> Subject: Re: Indicating thermometer
>
>
>
>
>
>
> It may be the thermometer with digital display that gives an
> indication when the temperature reaches the set maximum level.
>
> Also it may be the thermometer with digital display which facilitates
> instant observation rather than looking at the dial, in the case of dial
> thermometer / the scale in the stem type mercury or alcohol filled one.
>
> Thu, 27 Jul 2006 Vinod V wrote :
> >
> >
> >Dear List,
> >
> >In page 204 of the "Fish & Fisheries Hazards & Controls Guidance :
> 3rd edition, in the control strategy for hydrated batter mix control,
> under
> the head - How will monitoring be done ? There are 5 options out of which
> the
> 5th option is, using an indicating thermometer.
> >
> >What is an indicating thermometer ? Aren't all the thermometers
> indicating thermometers or are these any specific type of thermometers ?
> >
> >Please clarify.
> >
> >Regards
> >
> >Vinod
> >INDIA
>
>
> With regards,
>
> Dr.R.Viswanathan,Ph.D.,
> Professor,
> Department of Food and Agricultural
> Process Engineering,
> Tamil Nadu Agricultural University,
> Coimbatore -641 003.
> Phone: 0422-5511272 / 5511282
>
> Res: #12, Sowbhagya Nagar,
> A - Block, Opp. to KMCH, Civil Aerodrome, P.O., Coimbatore -641 014.
>
> Phone: 2629711
>
>
> <http://adworks.rediff.com/cgi-bin/AdWorks/sigclick.cgi/www.rediff.com/signat
> ure-home.htm/1507191490@Middle5?PARTNER=3>
>
>
Amilcar Caputo
Cell: (714) 448 5355
This archive was generated by hypermail 2b29 : Thu Jul 27 2006 - 08:11:00 PDT