Temperature sensors prevention

Improved sensors allow computer monitoring of the system for safety and protection of the equipment from damage. Sensors include lubrication-flow monitors and alarms, bearing-temperature sensors, belt scales, rotation sensors, and proximity sensors to detect ore level under the crusher. The latter prevent jamming of the output with too high an ore level, and protect the conveyor from impact of lumps with too low an ore level. Motion detectors assure that the conveyor is moving. Control applied to crusher systems including conveyors can facilitate use of mobile crushers in quarries and mines, since these can be controlled remotely by computer with reduced labor. 

Afterburn Control. Afterburn is the term for carbon monoxide burning downstream of the regenerator this causes an increase in temperature upstream of the expander. Temperature sensors in the gas stream cause the brake to energize. This provides sufficient resisting torque to prevent acceleration until the afterburn is brought under control by water or steam injection. 

Dry heat sterilization is usually carried out in a hot air oven which comprises an insulated polished stainless steel chamber, with a usual capacity of up to 250 litres, surrounded by an outer case containing electric heaters located in positions to prevent cool spots developing inside the chamber. A fan is fitted to the rear of the oven to provide circulating air, thus ensuring more rapid equilibration of temperature. Shelves within the chamber are perforated to allow good air flow. Thermocouples can be used to monitor the temperature of both the oven air and articles contained within. A fixed temperature sensor connected to a chart recorder provides a permanent record of the sterilization cycle. Appropriate door-locking controls should be incorporated to prevent interruption of a sterilization cycle once begun. 

The MARS-S is constituted of a multimode cavity very close to domestic oven with safety precautions (15 mL vessels up to 0.5 L round-bottomed flasks, magnetic stirring, temperature control). The magnitude of microwave power available is 300 W. The optical temperature sensor is immersed in the reaction vessel for quick response up to 250 °C. A ceiling mounted is available in order to make connection with a conventional reflux system located outside the cavity or to ensure addition of reactants. These ports are provided with a ground choke to prevent microwave leakage. It is also possible to use a turntable for small vessels with volumes close to 0.1 mL to 15 mL vessels (120 positions for 15 mL vessels). Pressure vessels are available (33 bar monitored, 20 controlled). 

Sensors were inserted in the prototype to monitor the temperature (National Semiconductors, LM35-DZ), humidity (Honeywell, HIH-3605-B) and total VOC concentration (FIS, SP3-AQ2) at various locations shown in Fig. 12.8-10. The data were collected by a data logger (Picolog, ADC-16) and analyzed. The temperature profiles from the preliminary test showed that poor seal between the hot and cool air streams compromised the prototype performance. Hot spots and uncontrollable temperature rise prevented further tests. This clearly showed that the complicated design is not suitable. 

The introduction of seed crystals to a solution that is saturated or within the lower portion of the metastable zone prevents spontaneous nucleation (Karpinski et al. 1980). In most industrial cases, seeding is a manual operation. The indication of when to seed is derived from an indication of the process temperature, typically provided by the control system, and knowledge of the product solubility and current solution concentration, whether measured on-line, off-line, or calculated from charge amounts. Obviously, accurately calibrated temperature sensors in the laboratory, where the solubility relationship was established, as well as in the crystallizer, where the solubility relationship will be utilized, are necessary. 

Control of the aforementioned problems requires an additional temperature sensor in each zone and a means for changing the mixing rate characteristic of the burner in response to the temperature measurements. Burners with adjustable spin (swirl) can be set to prevent much of the problem, especially if combined with a low-fire, forward-flow gas or air jet through the center of the burner. Such a jet is typically sized for 5% of maximum gas or air flow. 

To prevent this problem, all control sensors should be close to the level of the tops of the loads. Input control sensors should be within about one-fourth of their zone length from the load entry end of their zones. Over-temperature sensors should be 5 to 10% of their zone length from the exit end of their zones, and set at the maximum furnace temperature allowed. With such a sensor-positioning arrangement, a modem quick-recovery temperature control has a chance to avoid a heat delay following a mill delay. 

This novel control system can raise productivity by 10% or more, depending on the mill operation. Maximum benefits will be gained in a mill with many delays. After a delay, the early temperature sensor will detect the newly cold pieces much earlier, thereby promptly increasing firing rate to prevent further delay. The second sensor prevents the very hot load pieces in the furnace during the delay from being overheated. 

Fig. 5.17. Schematic piping for diiution air for a recuperator. TSBA = temperature sensor for controi of bieed-off air, TSDA = temperature sensor for control of dilution air. Both elbows at the right function as in fig. 5.21 to prevent radiation between recuperator and the furnace load from damaging either. Both eibows aiso assure good mixing between the furnace poc and dilution air, and both eibows prevent the TSDA from being fooled by seeing hotter or colder surfaces in the furnace or recuperator. If a velocity thermocouple at or near the same location, or a wall-mounted sensor, is found to be reading, say, 50° low, the setpoint should be adjusted 50° lower to protect the recuperator.

Fig. 6.24. Three-zone reheat furnace temperature control for best productivity, least fuel rate. This control system minimizes scale formation by preventing overheating. Scale accumulation forces bottom zone gases to top zone, reducing bottom side heating. PV = process variable SP = setpoint T/s = temperature sensor.

Figure 17.69 depicts the schematic representation of the three principal thermal analysis systems—the classical DTA system with a single heat source and temperature sensors within the sample and the reference the Boersma DTA with a single heat source having the temperature sensors on the outside of the sample and reference and the DSC, where the power to individual heaters located in the sample and reference holders is varied continuously in response to sample thermal effects to prevent the development of a differential temperature between the sample and reference channels [142]. 

The ASM typically consists of an air blower or an air compressor, a filter, a flow meter, a pressure sensor, a humidifier, and a temperature sensor, as shown in Figure 1.16. The blower or compressor sends ambient air with boosted pressure into the fuel cell system. A picture of an air blower is shown in Figure 1.17. The mesh filter (MFT) prevents large objects from... 

Up to now, adaptronics has mainly been an object of research at universities, and the industry has only just started to apply adaptronic systems a most recent example is an intelligent mineral casting mould [182]. This machine bed for machine tools is to adapt itself to changing thermal conditions, thereby preventing the structure from any deformations. To accomplish this, temperature sensors are embedded into the mineral casting material (polymer concrete) cooling elements, which are integrated into the bed, serve as actuators. 

It is not unknown for Dewars and cryostats to spring a leak. If this happens, the loss of vacuum results in a loss of thermal insulation. The increase in evaporation rate will then lead to complete loss of liquid nitrogen over a short time and warm-up of the detector. If a detector is allowed to warm up while the bias supply is connected, damage will be caused to the preamplifier. To prevent this, every detector system should have a temperature sensor and some means of switching off the bias if the detector warms up, whatever the failure - mechanical or human. Most bias supplies suitable for germanium spectrometry now have the appropriate cut-out built in and the detector manufacturers now routinely provide a temperature sensor. However, these systems do not work unless the user bothers to connect them together ... 

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