Non-invasive, energy-autonomous and wireless temperature sensor for the process industy
Temperature sensors for application in the process industry are typically mounted in a thermowell. These tubular fittings penetrate the surface of e.g. a pipe and allow to insert a temperature sensing element into the process medium. Although this invasive sensing is state-of-the-art, thermowells suffer from significant drawbacks: Any pipe penetration is a potential cause for leakage and the thermowell itself is prone to corrosion, abrasion and bending stress. Avoiding the thermowell by measuring temperature on the surface of the process container was so far not considered a widespread alternative to invasive sensing. The temperature of the surface is generally not considered representative for the temperature of the process medium. A surface sensor is strongly exposed to the ambient condition and, furthermore, the calibration of such a surface sensor is challenging. In this paper we demonstrate how to overcome these limitations by an optimized thermo-mechanical design and enhanced model-based sensing. In combination with energy autonomous operation and wireless communication our novel non-invasive sensor offers a remarkable flexibility enabling scenarios discussed within the context of internet of things (IoT).
Autonomous wireless sensors for process instrumentation - Autonome drahtlose Sensorik für die Prozessindustrie
As the primary means of collecting information about the process, field instruments are vital to the operation of plants in the process industry. Generally, communication and power supply of such sensors are done by hard wiring, which can be very complex and laborious. In particular, sensors in remote locations, on rotating parts, and sensors added to an already-operating plant instead of during commissioning could benefit the most from a wireless solution. Since a plant can only be operational if all necessary assets are functioning correctly, demands on reliability in the process industry are far more stringent than for consumer devices. Although specialized wireless solutions exist in the process industry since the 1960s, until now, they have been successful only in specialized markets or products. From the experience with fieldbus technology, it is clear that any wireless protocol that aims at achieving critical mass requires an industry standard with many device manufacturers adapting it. Such a standard is now established as wirelessHART, which combines state-of-the-art wireless technology with the ease of use of the HART protocol. Plants in process automation usually have a projected lifetime of about twenty years and longer. In order to maximize the return on investment, plant utilization should be as high as possible over the lifetime of the plant, thus unscheduled downtimes must be minimized. Asset monitoring is a new trend targeting to detect possible defects in equipment before they cause breakdown and to allow the root cause to be eliminated in a scheduled manner. In order to do so, additional sensor information is required, which further increases the number of sensors installed. For any sensor, total cost should be as low as possible in order to maximize the benefit. Since wiring and installation can amount to almost 90 % of the total cost for the device, wireless is a logical option in this scenario. Wireless devices and sensors offer more installation flexibility and reduced installation costs due to the absence of wiring effort. Although primary cells (batteries) offer an autonomous energy supply in principle, this solution suffers from strongly limited lifetime, and hence potentially high maintenance cost through battery exchange and increased risk of failure. Therefore, additional energy sources are necessary for a more efficient way of operating wireless devices. Energy harvesting (EH) offers to improve the maintenance-free lifetime of wireless devices into the lifetime range of process plants by using autonomios power supplies which are based on the convertion of ambient energy or energy coming from the process itself into usable electrical energy. In principle, this kind of energy exists in abundance in many processes, in forms such as thermal
Livestock Aspects of Feed Grain Policy
It is a signal event that our topic should be included on this program. In recent years, the livestock and poultry economy has scarcely been considered in the making of price and income policy for feed grains. It has been disregarded by pragmatic policy makers. It has been almost equally bypassed by theoretical economists, who usually kibitz freely. Policy for support and target prices for corn, grain sorghums, and other feed grains has been made with an eye almost exclusively fixed on the producers of those crops. The target price has been set relatively high in order to protect crop farmers' income. The latest (and current) loan rate policy has been to hold the rate low. Although a low rate facilitates moving grain into livestock and poultry consumption when crops are abundant, it does nothing to provide buffer stocks for years when crops are short. In addition, a couple of years ago it became administrative policy to dispose of the stocks inherited from an earlier period, even subsidizing their sale abroad. But the foremost example of one-sidedness is the attitude toward release prices. In all the rhetoric heard recently about the peril of holding corn or sorghums in reserve, the scold has been that release prices would not be set high enough. What group can the spokesmen have had in mind? Feed producers, of course! Not feed consumers, that is, livestock and poultry men. It has been a one-sided consideration of a two-sided issue. If all groups are to have equal voice in policy making, how can livestock and poultry interests be so ostracized? The one-sidedness has more impact now that so much livestock and poultry production has become detached from feed supply on individual farms. The livestock-poultry economy is therefore more sensitive to the availability and price of feed. It is in fact a contradiction that historically, livestock and poultry got more attention when they were still closely connected with feed production on the farm. In the early years of farm programs, the "ever-normal granary" was consciously designed to level out the supply and price of feed for livestock and poultry. Now that livestock and poultry have become more commercial and more vulnerable to a volatile feed situation, feed price stabilization has been progressively removed from the councils of farm policy. And the ultimate contradiction is that the alleged price-depressing perils of a feed reserve have been proclaimed in disregard of the fact that the main defense of feed grain producers' incomes is the target price-direct payment mechanism, not support prices. If grains on reserve should cause market prices to be reduced below target level, producers would get bigger direct payments, that is, producers with a base on their farm are protected in that way. Admittedly, production outside such a base would not be eligible for payment.