Combined pressure/temperature sensor

A combined pressure/temperature sensor for industrial application is for exactly these reasons not very useful. Figure 5.13 shows typical cavity temperature sensors. 

Process-variable feedback for the controller is achieved by one of two methods. The process variable can (I) be measured and transmitted to the controller by using a separate measurement transmitter with a 0.2-I.0-bar (3-15-psi pneumatic output, or (2) be sensed directly by the controller, which contains the measurement sensor within its enclosure. Controllers with integral sensing elements are available that sense pressure, differential pressure, temperature, and level. Some controller designs have the set point adjustment knob in the controller, making set point adjustment a local and manual operation. Other types receive a set point from a remotely located pneumatic source, such as a manual air set regulator or another controller, to achieve set point adjustment. There are versions of the pneumatic controller that support the useful one-, two-, and three-mode combinations of proportional, integral, and derivative actions. Other options include auto/manual transfer stations, antireset windup circuitry, on/off control, and process-variable and set point indicators. 

A regulator is a compact device that maintains the process variable at a specific value in spite of disturbances in load flow. It combines the functions of the measurement sensor, controher, and final control element into one self-contained device. Regulators are available to control pressure, differential pressure, temperature, flow, hquid level, and other basic process variables. They are used to control the differential across a filter press, heat exchanger, or orifice plate. Regulators are used for monitoring pressure variables for redundancy, flow check, and liquid surge relief. 

In addition to absolute pressure measurements, pressure sensors can be used to determine flow rates when combined with a well-defined pressure drop over a microfluidic channel. Integration of optical waveguide structures provides opportunities for monitoring of segmented gas-liquid or liquid-liquid flows in multichannel microreactors for multiphase reactions, including channels inside the device not accessible by conventional microscopy imaging (Fig. 2c) (de Mas et al. 2005). Temperature sensors are readily incorporated in the form of thin film resistors or simply by attaching thin thermocouples (Losey et al. 2001). 

R 18] [A 1] Each module is equipped with a heater (H3-H8) and a fluidic cooling (C03-C06). Temperature sensors integrated in the modules deliver the sensor signals for the heater control. Fluidic data such as flow and pressure are measured integrally outside the micro structured devices by laboratory-made flow sensors manufactured by silicon machining. The micro structured pressure sensor can tolerate up to 10 bar at 200 °C with a small dead volume of only 0.5 pi. The micro structured mass flow sensor relies on the Coriolis principle and is positioned behind the pumps in Figure 4.59 (FIC). For more detailed information about the product quality it was recommended to use optical flow cells inline with the chemical process combined with an NIR analytic or a Raman spectrometer. 

Figure 4.78 shows such a combination of standardized elements together with an adapter plate and a backbone element. The adapter plate allows the integration of, for example, pressure and temperature sensors. 

The key element in the wheel electronics is the sensor. Specially developed components for this application nowadays combine the pressure sensor, a temperature sensor, and the complete signal processing and data interface in the same hous-... 

One system, which combines calorimetric measurements with monitoring of temperature and pressure, encloses the sample in an inert cell, to which pressure and temperature sensors are attached. The cell is then enclosed in a bomb-like container and heated at a slow rate, between 0.5 and 2°C min by the integral furnace. Any rapid rise in pressure or in temperature during the heating indicates that the sample is undergoing a degradation, which may pose a risk. ... 

Cavity temperature sensors are usually placed near the flow path end or where they are needed for regulating and control functions such as the sequential control. A cavity temperature sensor near the gate or in combination with a pressure sensor, as already mentioned, makes little sense in the industrial environment, since most procedures are not based on an absolute measurement of temperature, but only evaluate and control or monitor relative information such as temperature changes. 

As shown in Table 3, various PMS index were examined by correlation analysis for the part weight. The total number of data for the analysis was 450. As a result, new PMS index, PIOc/TIOc, formed with a combination of pressure and tenqierature tog er showed the best result. The correlated data for the part weight with new PMS index is shown in Fig. 8. Even if the PMS index with pressure and tempa-ature showed the best eorrelation, it should be noted that the temperature used for the index could not represent the aetual temperature of the resin in the mold. The temperature sensor used in the experiment was installed at the mold wall. Although it gives faster response than any other temperature sensors installed in the mold, the measured temperature is the mold wall temperature not the resin temperature. If the resin temperature ean be measured with a high sensitivity and reliability, the PMS index proposed in this study may result in better eorrelation. 

From the above-given condensed review of the EEP detection methods one can infer that none of these methods can independently satisfy all the requirements specified for the study of heterogeneous processes involving the EEP participation. To our opinion, the application of semiconductor sensors for detection of EEPs can be provided by a combination of required qualities. The sensors are highly sensitive, miniature, can be operated within wide ranges of gas temperatures and pressures, and are made of simple devices. At the same time, a series of problems arise connected with the preliminary preparation of sensors and improving their selectivity. These and other questions of general nature will be considered in the section that follows. 

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