Energy recovery heating apparatus

Abstract

A heating device for providing heated air to the jacket of a pipe containing a product to be heated to, or maintained at, a predetermined temperature. The device comprises a housing 1 having an air in

Description

Title and indication of invention This invention relates to the recovery and replenishment of energy from food processing applications and its re-introduction back into the process as a primary source of thermal energy. Introduction and background Within the food and beverage manufacturing industry, there is a common requirement to keep foodstuffs at elevated temperatures. This is generally to ensure that the product is maintained at the correct temperature or viscosity, enabling it to be pumped through a network of pipes to the next stage of manufacturing or for packaging as the finished product. Heat maintains the viscosity of the product being pumped, facilitating the processing and safety of the product - examples of such foods are chocolate, glucose syrups, oils, fats, soups, jams and sauces. The method by which these ingredients are heated hasn't changed much over the last 100 years or so and it is a highly energy-intensive process. The common way to heat pipes containing viscous fluids such as chocolate, is to house the pipe containing them within a larger diameter pipe and pump hot water in the void between - referred to as hot water jacketing. Whilst effective, it brings many challenges around food safety and energy consumption. The invention is not limited to the application of pipes as tanks and storage vessels use a similar jacketed system. The water includes chemical inhibitors to reduce corrosion and bacteria but inevitably, the water will cause corrosion or become partially stagnant. Corrosion to the inner pipe or leaks from water fittings allows water to enter the food-carrying pipe and this water can be contaminated by bacteria such as salmonella. Also, the hot water is typically generated by burning gas, a practice most manufacturers would like an alternative to - typical energy saving will be around 80% to 90%. Summary of the invention The invention uses the existing jacketed pipe network. Water is drained from the jacket leaving an air void between the product pipe and the outer jacket. Fans will blow heated air into the void. The air is a closed-loop system allowing for recirculation. Air blown by just one fan in just one direction causes an unacceptable thermal gradient along the pipe in static flow conditions. The invention allows for the use of two fans, operating in opposing directions, and working in an oscillating fashion. Only one fan is working at any one time. Temperature sensors monitor the air temperature within the closed loop air and also the temperature of the heater which is attached to a finned heat sink. The entire jacketed pipe is insulated to minimise heat loss to atmosphere. In existing, water-jacketed pipework, the system is never insulated due to potential biohazards caused by water leaking into the insulation. The whole system is controlled by the controller, which receives thermal readings from at least 3 temperature sensors. The controller calculates how much heat to add due to the thermal losses through the insulation to maintain the food material at the required temperature. The heater adds the correct amount of energy to compensate for the losses. The controller selects which of the at least two fans to operate in which direction based upon several factors, which may or may not include: the length of the pipe, the number of spools (a spool being a jacketed pipe with end connections), the number of jumpers between spools, the type of spools fitted (e.g., bends, tees, straights). An algorithm is generated to accommodate each of these designs. The algorithm is optimised for each factor to generate the best thermal performance (accuracy) along the spool set. If the temperature of the product is higher than desired, the flowing air absorbs energy radiated by the product pipe and recirculates it to the heat sink where additional energy is added if required. The heater / fan assembly has a user interface which is accessible to the user and may be, but is not limited to, an LCD or LED display screen. The heater / fan housing has surface-mounted pushbuttons which allow the user to enter the desired temperature setting of the device, as well as access other control parameters. The device has at least 3 external LED status indicators to show the health and status of the fans and the heater. The heater may be powered by electricity. The invention allows for 90% less energy than a water-jacketed system to be used to maintain the product at the correct temperature. The invention removes the potential for product contamination due to water leaks. The invention allows for zero carbon emissions if a renewable electricity supply is used. Optional features The invention may have proprietary communication means, such as a fieldbus communication system, allowing for data to be transmitted to and received from a central control panel. The data may be, but are not limited to, thermal setpoints, thermal readings, health status of the fans, health status of the heater, system status alarms and notifications and power usage. As the communications system is built into the controller, it cannot be shown individually on an exploded drawing; it is merely a printed circuit board component. Introduction to detailed description In the drawing below, the main body of the unit lisa moulded housing which contains all the necessary components of the invention. 10 is a heater which may or may not be an electrically powered cartridge resistance heater. The heater is directly attached to a finned heat sink 11. The purpose of the heat sink 11 is to absorb the thermal energy of the heater 10 when it is switched on by the controller 30. The heat sink 11 may or may not be an aluminium extrusion. The heat sink 11 has a thermal sensor 21 which relays thermal readings to the controller 30. A thermal fuse 12 is mounted on the heat sink 11 and operates as a safety device should a fault occur. The purpose of the thermal fuse 12 is to prevent over-temperature of the invention due to a faulty sensor 21 or a software fault in controller 30. The body of the invention 1 has insulation in a chamber 13 to mitigate thermal losses from the heater 10 and heat sink 11. The fans 40,41 blow air on demand into the heat sink 11. The fans 40, 41 are controlled by software in the controller 30. Temperature sensors 20,22 send thermal readings to the controller 30. The controller 30 determines which fan 40,41 should be switched on. Sensor 20 is used by the controller 30 to switch on fan 40. The controller uses sensor 22 to switch on fan 41. The direction of air flow for fans 40, and 41 is always through the heat sink. Air will be blown through the end caps 2,3 into the hose which feeds the jacket of the food-carrying pipe. The end caps 2, 3 have vortex swirls within them to accelerate the velocity of the air into the hose. The housing 1 incorporates an LCD display 31 which is used by the operator to select the desired temperature by operation of the up / down selector buttons 32. The selected values are used by the controller 30 to control the heater 10 and the fans 40, and 41. Thermal conditions may or may not exist where neither fan 40,41 nor heater 10 will be switched on. The end caps of the unit 2, 3 which may or may not be part of the housing 1 moulding. The end caps 2, 3 are designed to create a swirling vortex of air into the jacket to manage the optimal velocity profile. The heater 10 is housed in the heat sink 11. The heater 10 heats the heat sink 11 to provide a large surface area from which the fans 40, 41 blow the thermal energy into the system. The heater 10 may or may not be a cartridge heater. The housing 1 incorporates LED lighting 50, 51 52 which may be lights or rings. The controller 30 will control the output colour of the lights 50,51,52 to indicate the health and status of the fans 40,41 and the heater 10.

Claims

First claimThe claim is for a device used as an energy recovery and thermal replenishment device for industrial processes to maintain or raise product temperature using a heater, heat sink and bi-directional fans controlled by a controller.Second claimThe bi-directional airflow allows for energy recovery and enhancement to allow for product temperature to be raised giving a change of product phase from solid to liquid in static flow conditions.Amendments to the Claims have been filed as follows:PATENT CLAIMSFirst claimThe claim is for a device used as an energy recovery and thermal replenishment device for industrial processes to maintain or raise product temperature using a heater, heat sink and two opposing direction fans controlled by a controller. The heat sink is defined as a metal finned device which may or may not be made from aluminium and contains a resistive heater. On demand from the controller the heater switches on and heats up the heat sink from which one of the fans will dissipate the heat in a certain direction into the jacketed pipe.

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