Resistance Thermometers B 90.2820.0.2 Operating Instructions
Contents
1. Resistance Thermometers for use in areas with an explosion hazard Ex areas Persons concerned Experienced professional electricians as per EU Guideline 1999 92 EC and trained personnel B 90 2820 0 2 Operating Instructions 05 04 00404304 Contents Equipment and intended application Marking Safety notes Conformance with standards Technical data explanation and example 5 1 Intrinsically safe Ex i protection 5 2 Flameproof enclosure Ex d protection 5 3 Use in areas with a dust explosion hazard Installation Maintenance Connection circuits for resistance thermometers Attachments Declaration of conformity data sheet oo w amp wo 1 Equipment and intended application Resistance thermometers from JUMO are used as intrinsically safe and or flameproof equipment for temperature measurement in liquid and gaseous media as well as for dusts The thermometers consist of a protection fitting with various process connection options a terminal head or a connecting cable and an interchangeable measuring insert depending on the type All fittings in contact with the process media undergo a leakage test The Pt100 temperature sensors mounted in the fittings are to EN 60 751 in tolerance classes A or B in a 2 3 or 4 wire circuit see Section 8 It is also possible to use these sensors with a higher reference value Pt500 Pt1000 Pt2000 Pt5000 NTC sensors such as KTY or other PTC sensors may al2. 80 C W TS 130 C 0 88 C 129 12 C So the maximum temperature the medium temperature being measured on the probe tip must not exceed 129 12 C since in the event of a fault it is possible that the limit for the temperature class will be exceeded DANGER OF EXPLOSION If a transmitter is to be used in a thermometer that has a terminal head then the permissible operating limits for the transmitter must also be taken into account The transmitter is hermetically sealed into the terminal head The ambient temperature and the heat conducted through the protective fittings from the medium being measured both contribute to a rise in surface temperature and the temperature within the terminal head The self heating and heat conduction from outside via the protective fittings have been determined for the worst case of a measured temperature of 300 C and the maximum power dissipation of the transmitter of 750 mW In such a situation the temperature of the terminal head is 18 C higher than the ambient temperature It is necessary to take account of the ambient temperature conditions prevailing in the application and to check that the transmitter is being operated within its specifications and thus does not itself present an explosion hazard The values specified in the type examination certificate for the transmitter that is used must be observed and adhered to Transmitter example Temperature measurement in class T4 max 135
3. This is achieved through the following regulations No dust deposit The surface temperature must not exceed 7l5 of the ignition temperature in C for the corresponding dust air mixture With dust deposit Surfaces on which a dangerous accumulation of smolderable dust cannot be prevented must not have a temperature that is higher than 75 C below the smoldering temperature of the dust concerned If layers thicker than 5 mm occur a further reduction of the surface temperature must be applied Where a combination of swirling and deposited dust occurs the lower of the values derived above must be applied Note In this case surface means the exterior surface of the equipment see also EN 50281 1 1 and 2 The ignition or smoldering temperature of the dust or dust air mixture that is present must be defined or determined by the operator of the plant or system Reduction of the maximum permissible surface temperature with increasing thickness of the dust layer 400 Smoldering temperature 5 with a 5 mm thick layer g gt 5 400 C lt Ts 3 300 iji 5 400 C 320 C lt Tsmm lt 400 C ge 250 C lt Tsmm lt 320 C H S 5 E 200 2E 320 C n 3 23 E 5 100 a 250 C gt 0 0 10 20 30 40 50 Thickness of layer in mm 6 Installation The valid European and national regulations must be observed for installation and operation The generally accepted state ofthe art and these ope
4. C ambient temperature of the terminal head 40 C temperature rise in head 18 C The resulting maximum temperature in the terminal head is 40 C 18 C 58 C The transmitter used is a JUMO dTrans T01 as per data sheet 95 6550 in II1G and its maximum ambient temperature when used in class T4 is 60 C Since 58 C lt 60 C this transmitter can be operated inside the terminal head for temperature class T4 with these ambient condition 5 2 Flameproof enclosure Ex d protection The components that could ignite a potentially explosive atmosphere are arranged within a flameproof enclosure here terminal head with cable gland that is capable of containing the internal pressure caused by an explosion of an explosive mixture inside and prevents the explosion from being propagated to the potentially explosive atmosphere surrounding the enclosure The underlying principle is safe containment in the event of an explosion It is not mandatory to connect the versions in flameproof enclosure to intrinsically safe circuits however it must always be ensured that the rise in temperature of the thermometer remains limited as was described in detail in Section 5 1 and demonstrated by the case studies The temperature classes and safety reserves apply equally to both protection types and the temperature development in the terminal head if used with a built in transmitter must also be taken into account For operation in Zone 0 G or 20
5. D type d protection Flameproof enclosure is by no means sufficient by itself 5 3 Use in areas with an explosion hazard caused by dust Dust explosion protection safe limitation of energy For the safe limitation of the energy fed to the sensing element also in the event of a fault of the supply unit using a circuit with intrinsic safety protection is highly appropriate The protection type Protection through enclosure means that in the area with an explosion hazard caused by dust the only criterion is the characteristic of safe limitation of electrical variables in the intrinsically safe equipment by means of the associated intrinsically safe devices Head mounted transmitters in Category 1G or 2G are included in the Protection through enclosure type of protection inside the terminal head The associated intrinsically safe device that has to be positioned outside the hazardous area need not meet the requirements of Category 1D or 2D The category markings for equipment requirements in areas with an explosion hazard caused by gas 1G or 2G are therefore sufficient for the intrinsically safe equipment or associated intrinsically safe devices The following temperature values must be taken into account for applications in areas with a dust explosion hazard Applicable to all zones The surface temperature of the equipment must not rise to a level that could ignite swirling dust or dust deposits on the equipment
6. d 10 C for temperature classes T1 and T2 5 C for classes T3 T6 Category 2 an additional safety reserve reduction must be applied 10 C for temperature classes T1 and T2 5 C for classes T3 T6 The surface heating itself is influenced by the design of the temperature probe by the ambient conditions thermal coupling with the medium being measured and the power that is applied The self heating of the thermometer is characterized by the protection tube constant SK in C W which represents the increase in surface temperature in still air above the ambient temperature as a function of the applied power The protection tube constant SK is determined by JUMO and can be found in the attached data sheet on the affixed label The user must determine whether the thermometer is suitable for the measurement application and the connected equipment under the given conditions The maximum permissible measured temperature at the probe tip can be found from the following equation Ts Tk P x SK Ts Maximum permissible temperature at the probe tip Tk Maximum permissible surface temperature depending on the temperature class as in the table reduced by the safety reserve P Power in the certified intrinsically safe circuit SK Protection tube constant see technical data sheet The following diagram illustrates an example of self heating of the probe surface of a resistance thermometer as a function of the applied power and thus the tem
7. nnection to intrinsically safe circuits When connecting up to circuits that are not intrinsically safe the user must ensure that the power applied is limited in such a way that the maximum rise in surface temperature is no greater than that specified for the temperature class minus the safety reserve See also Section 5 of these operating instructions 2 Marking The designation for the resistance thermometer used is marked on the terminal head or permanently attached nameplate For every resistance thermometer that is marked by an individual type designation e g 90 2800 9101 there is a corresponding probe specific drawing and data sheet The appropriate marking ensures that all sensors are unambiguously identifiable and traceable The probe specific values can be found in the drawing the technical data sheet and or the label that is affixed to these operating instructions 3 Safety notes The technical data that are relevant to the use of the device in an area with an explosion hazard Ex area are presented in the corresponding technical data sheet and or the label that is affixed to these operating instructions Only operate resistance thermometers according to their intended use and in a clean and undamaged state It is not permissible to make any alterations to the resistance thermometers In such a case proper fault free operation is no longer assured The guarantee is also invalidated by any alterations When exchanging measuring in
8. perature arising within the probe Self heating is independent of the protection type and also applies to the flameproof enclosure 250 0 600 Surface temperature E Internal temperature Linear surface temperature 500 200 0 400 150 0 300 100 0 200 Internal probe temperature C Increase in surface temperature C 100 0 0 T T 7 T T 0 0 5 1 1 5 2 2 5 3 3 5 Power W Diagram Self heating of a Pt100 resistance thermometer Example 1 A thermometer is to be used in temperature class T4 maximum temperature 135 C safety reduction of the limit 5 C Protection tube constant SK 80 C W Maximum power in the circuit P 0 5 W TS 130 C 0 5 W x 80 C W TS 130 C 40 C 90 C So the maximum temperature the medium temperature being measured on the probe tip must not exceed 90 C since in the event of a fault it is possible that the limit for the temperature class will be exceeded DANGER OF EXPLOSION Example 2 The same thermometer is to be used in the same application as above but this time using the JUMO transmitter TRANS T01 which has a considerably lower maximum power thus permitting a substantial increase of the maximum temperature being measured and so a wider range of applications Protection tube constant SK 80 C W Maximum power in the circuit P 0 011W JUMO transmitter Type 95 6555 TS 130 C 0 011 W x
9. rating instructions must be applied Resistance thermometers from JUMO are used to measure temperature within areas with an explosion hazard containing flammable or non flammable materials gases air gas mixtures or potentially explosive dusts In the case of equipment with type Ex i protection the supply of power and evaluation are performed by certified intrinsically safe circuits The resistance thermometers are mounted by means of the process connection on site The resistance thermometer may need to be built into an additional screw in or weld in pocket depending on the process connection If a thread is provided as a process connection then the entire thread length of the resistance thermometer must be in contact The connecting leads to the resistance thermometer must have a fixed installation if they are attached to containers or piping that contain potentially explosive air gas mixtures or dusts Zone 0 20 or Category 1D and 1G either continuously or over long periods Metallic connector housings must be grounded via the connecting cables for equipotential bonding Non metallic connector housings must not exceed the max surface area specified by EN 50 284 4 4 The screw in or weld in pocket can also serve to separate zones and is made from steel stainless steel Hastelloy etc with a minimum wall thickness of 1mm Caution In all cases zoning is the responsibility of the plant system operator and not of the manufact
10. serts use only original JUMO replacement parts of the same type The national and international safety and accident prevention regulations must be followed for installing and working with resistance thermometers Furthermore the operator of the plant or system is responsible for the observance of legal requirements If lead extensions are used the specified length dependent limits for capacitance and inductance must be observed 4 Conformance with standards The resistance thermometers meet the requirements of EN 50014 1997 A1 A2 1999 EN 50020 1994 EN 50281 1 1 1998 EN 50284 1999 EN 1127 1 1997 EN 50018 2001 A1 2003 The JUMO quality management system to EN ISO 9001 is the basis for conformance with the EU guideline 94 9 EC Annex IV ATEX The resistance thermometers have been developed manufactured and tested in accordance with the state of the art and in conformity with the applicable standards and regulations 5 Technical data CAUTION for specific data see the attached technical data sheet and or the label that is affixed to these operating instructions 5 1 Intrinsically safe connection type Ex i protection The equipment used in areas with an explosion hazard only contains intrinsically safe circuits A circuit is intrinsically safe if both in normal operation and in the event of a fault a short circuit of the circuit does not produce a spark capable of causing ignition and the current flowing through the equipmen
11. so be used Versions with two or three measurement circuits can be provided A transmitter can be integrated into the terminal head for measurement transmission with a standard signal e g 4 20mA The thermometers fulfil the requirements for Explosion Group ll in Categories 1 G and 1 D as well as 2 G and 2 D They are thus suitable for use in areas with an explosion hazard Zone 1 or Zone 2 with gas Gas and Zone 21 or 22 with dust Dust Depending on the circumstances it may be permissible for the probe stem to protrude into the Zone 0 or 20 area zone separation The thermometer parameters that are specific to a given type can be found in the corresponding technical data sheet see attachement and or on the label that is affixed to these operating instructions Depending on the measurement task and the application requirements the resistance thermometers are available with different terminal heads a variety of process connections matching pockets with or without a interchangeable measuring insert and with or without a fitted connecting cable Resistance thermometers with type Ex i protection are certified for connection to intrinsically safe circuits in Category ib for use in Zones 1 and 2 with an isolator in Zone 0 and in Category ia where the stem is in Zones 0 1 or 2 Resistance thermometers in flameproof enclosure terminal head and cable gland are also equipped with intrinsically safe measuring inserts for co
12. t does not heat any part of the surface above the level specified for the temperature class see also EN 50020 In order for a circuit to be designated as intrinsically safe every individual device included in the circuit must be designed to be intrinsically safe Furthermore it is necessary to test that the complete circuit configuration of the individually intrinsically safe devices forms as a whole an intrinsically safe circuit The fact that a circuit is assembled from devices that are individually intrinsically safe does not guarantee that the circuit as a whole is intrinsically safe For instance the sensing element in a resistance thermometer carries a current during measurement This produces internal heating of the element and as a result an increase in the temperature on the surface of the protective fitting So it is necessary to ensure that the limits of the given temperature class are not exceeded Temperature classes for the equipment flammable materials 450 C 300 C 200 C 135 C 100 C 85 C gt 85 lt 100 C Explanation The following safety reserves must also be complied with Category 1 as per EN 1127 1 1997 Item 6 4 2 hot surfaces the temperature of any and all surfaces of equipment used in Zone 0 that can come into contact with a potentially explosive atmosphere must not exceed 80 of the ignition temperature gt Temperature class minus 20 An additional reduction must be applie
13. ternet www jumo co uk JUMO PROCESS CONTROL INC 885 Fox Chase Suite 103 Coatesville PA 19320 USA Phone Fax e mail Internet 610 380 8002 1 800 554 JUMO 610 380 8009 info JumoUSA com www JumoUSA com
14. urer supplier of the equipment Gases mists vapors Potentially explosive Guide values atmosphere present ste long term or frequentiy long term or frequently gt 1000 hours year occasionally 10 1000 hours year infrequently short term lt 10 hours year 7 Maintenance The valid European and national regulations must be observed for maintenance servicing and testing During maintenance all parts must be tested that are relevant for the Ex explosion protection rating In addition thermometers with a plastic terminal head as well as all plastic components e g connectors and the like must only be cleaned with a damp cloth to avoid building up an electrostatic charge 8 Connection circuits for resistance thermometers applies to both head mounted and cable connected RTDs from JUMO 2 wire circuit A S 3 wire circuit A 4 S 4 wire circuit A S 2 x 2 wire circuit a S S 2 x 3 wire circuit a a S 2 x 4 wire circuit q O 3 x 2 wire circuit pu pu S S JUMO GmbH amp Co KG Street address Moltkestra e 13 31 36039 Fulda Germany Delivery address Mackenrodtstra e 14 36039 Fulda Germany Postal address 36035 Fulda Germany Phone 49 661 6003 0 Fax 49 661 6003 607 e mail mail jumo net Internet www jumo net JUMO Instrument Co Ltd JUMO House Temple Bank Riverway Harlow Essex CM20 2TT UK Phone 44 1279 635533 Fax 44 1279 635262 e mail sales jumo co uk In
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