Instrumentation symbols temperature

The hot section (Fig. 5) is controlled by a cascade loop which is based on a selected pumping rate (150 gpm) and sterilization temperature set in the TIC. Changes in the feed temperature are monitored at TTl which will automatically override the steam supply to keep the temperature at set point. Steam flow rate is monitored (by FE) and flow is automatically compensated should a large drawdown of steam occur elsewhere in the plant. Temperature is recorded at the beginning and end of the hot section. The hot section should be well insulated and special care should be given to the pipe supports for expansion. (Instrumentation symbols used here and in Figs. 3, 5, 6 and 7, conform to the standard symbols of the Instrument Society of America.)... 

Symbols for instrumentation are usually based on the standard reference Basic Instrumentation Symbols RP5 developed by ISA. Instrumentation symbols fall into three categories temperature, pressure, and flow indicators. 

Figure 12-61D. Centrifugal compressor surge control schematic diagram shows instrumentation required when primary flow-measuring device is located in centrifugal compressor discharge line. Symbols T = temperature P = pressure A = differential across compressor outlet to inlet. See Reference 89 for a detailed discussion. (Used by permission White, M. H. Chemical Engineering, p. 54, Dec. 25,1972. McGraw-Hill, Inc. All rights reserved.)...

The size of the kelvin, the SI temperature unit with symbol K, is defined by the statement that the triple point of pure water is exactly 273.16 K. The practical usefulness of the thermodynamic scale suffers from the lack of convenient instruments with which to measure absolute temperatures routinely to high precision. Absolute temperatures can be measured over a wide range with the helium-gas thermometer (appropriate corrections being made for gas imperfections), but the apparatus is much too complex and the procedure much too cumbersome to be practical for routine use. 

To analyze the instrument performance, the DSC shown in Fig. 4.54 is used. Note that in the literature cited to this appendix the used quantities are represented by different symbols thanusedhere [2,3]. The furnace or block temperature T is called often T(, (hence Tzero method). The heat-flow rate called dQ/dt = is called q in [2], and should not to be confused with the here used rate of temperature change dT/dt = q. The temperature difference used in Chap. 4 and maintained here is written as AT = Tr - Tj, a positive quantity on heating of a sample run versus an empty pan, giving a positive differential heat flow into the sample. (In [2,3], in contrast, AT is set equal to T, - T, making proportional to - AT). 

Fig. 1. The light-minus dark ENDOR signals of the multiline in the samples, control(EG-H)(a), deuterated(EG-D) (b) and GS-H(c). Positions of each pair of lines corresponding to two nuclear spin orientations are indicated by symbols, a-a to f-f . Instrumental conditions microwave frequency, 9.12 GHz power, 1.8 mW FM frequency 10 kHz depth, 60 kHz rf power, 250 W(about 4 G) temperature, 5.5 K for the samples EG-H and EG-D and 4.5 K for GS-H magnetic field, 3440 G. The trace represents the result of eight times data accumulation.

Fig. 3. Representation of a two heat-flux calorimeter showing (a) Boersma thermocouple placement and (b) the Tian-Calvet design. The schematic diagram (c) is appropriate for analysis of the response of both types of calorimeters. Symbols in (c) are subscript T refers to temperature, R refers to reference the temperatures of the block, sample, container, reference, and reference containers given by Tb, Tsc, T-r, Trq, respectively capital R refers to heat transfer resistance in the instrument (9).

FIGURE 18.52 Instrumentation diagram of a temperature control system for a stirred tank reactor symbols electrical instrument line, TT temperature transmitter, TRC temperature recorder-controller. 

The symbol used on a diagram for a plate column should indicate the type of tray used in the system bubble-cap, valve, or sieve. The first distillation column was invented in 1917. Today, a number of modifications allow modern process technicians to operate much more efficiently. The design, however, still includes the original still-on-top-of-a-still approach. The basic components of a plate distillation column are a feed line feed tray stripping section below the feed line enriching or rectifying section above the feed line overhead vapor outlet, side-stream outlet, and bottom outlet reboiler instrumentation for level, temperature, flow, pressure, and composition control outer shell and a top reflux line. 

As we here are mainly interested in adsorption measurement techniques for industrial purposes, i. e. at elevated pressures (and temperatures), we restrict this chapter to volumetric instruments which on principle can do this for pure sorptive gases (N = 1), Sect. 2. Thermovolumetric measurements, i. e. volumetric/manometric measurements at high temperatures (300 K - 700 K) are considered in Sect. 3. In Section 4 volumetric-chromatographic measurements for multi-component gases (N>1), are considered as mixture gas adsorption is becoming more and more important for a growing number of industrial gas separation processes. In Section 5 we discuss combined volumetric-calorimetric measurements performed in a gas sensor calorimeter (GSC). Finally pros and cons of volumetry/manometry will be discussed in Sect 6, and a hst of symbols. Sect. 7, and references will be given at the end of the chapter. 

Finally the shape of the temperature trend is very different from that of the valve position. This is caused by the inertia of the system. The heater coil will comprise a large mass of steel. Burning more fuel will cause the temperature in the firebox to rise quickly and hence raise the temperature of the external surface of the steel. But it will take longer for this to have an impact on the internal surface of the steel in contact with the fluid. Similarly the coil will contain a large quantity of fluid and it will take time for the bulk temperature to increase. The field instrumentation can add to the lag. For example the temperature is likely to be a thermocouple located in a steel thermowell. The thermowell may have thick walls which cause a lag in the detection of an increase in temperature. Lag is quite different from deadtime. Lag does not delay the start of the change in PV. Without deadtime the PV will begin changing immediately but, because of lag, takes time to reach a new steady state. We normally use the symbol r to represent lag. 

The abbreviations for each technique have already been noted (see Tables II and III). In polymer studies, however, the distinction between Tg and TG may cause confusion. Here the abbreviation TG refers to thermogravimetry, while Tg represents the glass transition temperature. This has caused a number of investigators and instrument manufacturers to use TGA for TG to avoid confusion. Other aspects of the use of symbols are mentioned in the following list. 

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