Temperature monitoring pyrometers

By inspection windows and use of a pyrometer, visual inspection of the catalyst and temperature monitoring on-site in a contactless manner were performed. It turned out that a glowing, homogeneous texture occurs at catalyst temperatures between 900 and 1200 °C, GHSV values up to 10 h and pressures less than 1 MPa [3]. This is an indication of the absence of soot deposits. At lower temperatures or... 

Reaction furnace temperature monitored by an optical pyrometer. 

Special high-temperature FPA imaging pyrometers—for special high-tempera-ture applications such as furnace temperature monitoring. 

Control Devices. Control devices have advanced from manual control to sophisticated computet-assisted operation. Radiation pyrometers in conjunction with thermocouples monitor furnace temperatures at several locations (see Temperature measurement). Batch tilting is usually automatically controlled. Combustion air and fuel are metered and controlled for optimum efficiency. For regeneration-type units, furnace reversal also operates on a timed program. Data acquisition and digital display of operating parameters are part of a supervisory control system. The grouping of display information at the control center is typical of modem furnaces. 

The deterrnination of surface temperature and temperature patterns can be made noninvasively using infrared pyrometers (91) or infrared cameras (92) (see Infrared technology and raman spectroscopy). Such cameras have been bulky and expensive. A practical portable camera has become available for monitoring surface temperatures (93). An appropriately designed window, transparent to infrared radiation but reflecting microwaves, as well as appropriate optics, is needed for this measurement to be carried out during heating (see Temperature measurement). 

Chemat and his coworkers [92] have proposed an innovative MW-UV combined reactor (Fig. 14.7) based on the construction of a commercially available MW reactor, the Synthewave 402 (Prolabo) [9[. It is a monomode microwave oven cavity operating at 2.45 GHz designed for both solvent and dry media reactions. A sample in the quartz reaction vessel could be magnetically stirred and its temperature was monitored by means of an IR pyrometer. The reaction systems were irradiated from an external source of UV radiation (a 240-W medium-pressure mercury lamp). Similar photochemical applications in a Synthewave reactor using either an external or internal UV source have been reported by Louerat and Loupy [93],... 

Record of the heat treatment temperature cycle shall be monitored by attached thermocouple pyrometers or other suitable methods to ensure that the requirements are met. See para. GR-3.4.12 for attachment of thermocouples by the capacitor discharge method of welding. 

All boiler temperatures were measured just prior to and after the collection of the coal samples and their respective fly ashes, since it was physically impractical to collect the samples and measure the temperatures at the same times. In all cases, the temperatures remained essentially constant. An optical pyrometer was used to measure flame temperatures, and water-cooled jacketed thermocouples were used to monitor the boiler temperatures. The wall effects on the temperature measurements were minimized by insertion of the thermocouple into the boiler until temperatures remained constant with distance upon further insertion of the thermocouple into the boiler. 

Unlike other thin film deposition processes, conditions for diamond CVD have three unique features (i) high substrate temperature typically at 700-1200 °C, (ii) high gas pressure P at 20-150Torr (lTorr= 133.3 Pa), and (iii) low methane (CH4) concentration of usually 1-5% with respect to the dilution gas, hydrogen (H2). A standard temperature for diamond growth, monitored by an optical pyrometer without emissivity correction, is 800 °C. It is, however, considered that the surface temperature of the specimen exposed to the plasma is actually higher. Under these conditions, at least more than 95% of the deposited film can be crystalline diamond,... 

The measurements on the research facility were carried out at stationary or quasi stationary conditions. The measurements of air flows, gas temperatures, gas composition, and heat output were analysed continously and monitored online. The gas composition was analyzed in the flue gas after the boiler exit with industrial gas analyzers. For the analysis of the hot gas in the reduction zone a suction pyrometer combined with a probe for detection was used. With this probe also short fluctuations could be monitored with extremely short delay. Besides, a hot gas sampling line with different analyzers for measuring the gas in the reburn zone was installed. Table 2 gives on overview over the gas analysis equipment. 

Heat is lost from the surface by conduction through the susceptor and mount, by forced convection of gas over the substrate, and by radiation to the reactor walls, provided the temperature of the substrate is sufficiently high. Endothermic chemical reactions also result in heat loss from the film. The substrate temperature is monitored with a thermocouple or an optical pyrometer and controlled using a traditional proportional-integral-derivative (PID) controller and power source. 

In the case of direct wafer heating by lamp heating there is a difference in the way heat arrives at the back side of the wafer. Now the main transfer route of heat to the wafer is that by radiation which is independent of the pressure. This implies that the wafer temperature can depend much more on the process pressure since pressure affects only the heat loss from the front side of the wafer. With the hot plate heating both the incoming and the outgoing fluxes are influenced by pressure which leads partly to cancellation. In addition the determination of the wafer temperature is even more complicated than in case of hot plate heating because the wafer has to be monitored directly (thermocouple against wafer or pyrometer). 

Local temperature Kulkarni et al. [74] demonstrated that it is possible to measure the local temperature using a pyrometer and that the local temperature is directly correlated with the current pulses observed during the electrical discharges. Furthermore, it is possible to obtain an indication of the local temperature by monitoring the gas film formation time [130]. 

Stack gas temperature measurements are taken to provide a basis for furnace continuous emission monitoring (CEM) and also to setup safety interlocks for emergency shutdown. Hence, accurate measurement of stack gas temperature is crucial to the operation of the furnace. The measurement location must be chosen in such a way that the bulk of the flue gases are sampled and the radiation from refractory tiles is minimal. A suction pyrometer is preferred to a thermocouple for stack gas measurement. Although not recommended, if an unshielded thermocouple is used, it must be corrected for radiative losses from the bead otherwise, the measurement would result in errors up to the order of 200°F to 400°F. 

The shell temperatures were monitored on the rotary kiln, preheater, and clinker cooler with an optical pyrometer. Shell thermal losses are given by a radiation and either natural or forced convection heat transfer, which are evaluated as follows (see Table 31.37 and Figure 31.23). 

Readout instruments to monitor operation of the system include pressure gauges, located at various points, an indicating pyrometer for the purifier, and temperature indication by vapor pressure thermometers at the inlet and exhaust of the expander. 

During high velocity CG/HW tests, samples were heated inductively to temperatures between 1100°C and 2500°C. Temperature measurements ofthe surface were also obtained by one-color and two-color pyrometry. Use of a two-color pyrometer was again employed to evaluate the spectral emittance ofthe oxidizing surface. Temperature gradients within the sample were measured by monitoring the temperature at the root of internal holes drilled to within 2.5 mm of the surface." ... 

All film depositions are performed in a stainless steel reactor, as shown in Fig. I. The base pressure is about 10 Pa the working pressure was 1 Pa for the samples shown. The precursors are introduced into the system with a carrier gas flow of 2 seem N2. The substrate is heated by a resistive ceramic heater, with a thermocouple controlling the temperature. The electrically heated tungsten filament is placed 4 cm above the substrate its temperature can be monitored by a pyrometer. 

Tube wall or skin temperature is an important reliability parameter and should be closely monitored, and guidelines for tube fife can be developed. Guidelines should be effectively communicated to operators so that appropriate mbe temperature can be determined that could meet the production requirement while minimizing the risk of mbe damage. It is important for operators to know that over-firing is the main cause of mbe damage. Process plants use skin thermocouples and infrared pyrometers to monitor TWTs. 

It is very important to monitor the amount of seale on mbes to measure coking/ fouling/corrosion rates. This can be achieved by a thermoeouple and infrared pyrometer monitoring program. The scales on mbe inerease TWT or skin tempera-mre. 0.01 in. scale on mbe could raise mbe surface temperature by 100 °F. The common way to get rid of scale is to sandblast the scale off the mbes while ceramic coating on tubes is a preventive measure however, the later is expensive. 

Sample connections, together with pressure, temperature and flow measurement points, are located at the inlet and outlet of the reformer and membrane modules to measure the performance of the RMM. A multipoint thermocouple is installed inside the first reformer tube in order to monitor the axial temperature profile along the heated catalyst length while two glass peepholes allow the reformer tube metal temperature to be measured by an infrared pyrometer. The control room is located in a safety area with a bird s eye view of the plant area. 

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