An object of the present invention is a solid fuel level sensor in furnaces equipped with a feeder.

The description of Soviet Union Patent No. SU 1638555A1 presents a measuring device (gauge) that, by an external lever, indicates whether a monitored fuel tank is full or not, thanks to the elements that come into contact with one another (closed) or stay open.

The description of U.S. Patent No. US3933041 presents a system and a method for measuring a level of bulk materials kept in bins, tanks and silos, based on a specific design of a chain. In this invention the chain is located along a vertical axis determined by two measuring points and an upper end of measuring chain is located above a surface of bulk material, and a lower end of measuring chain is located under the surface of bulk material. Measurement of the level of bulk material is carried out by establishing an angular displacement of the upper end of chain with respect to a start position of the lowest link of measuring chain.

A sensor according to the invention consists of aluminium profiles that are connected together with a possibility of the adjustment of arrangement angle of those profiles against one another. On each of the parts, a limit switch is installed together with a protection case that prevents entering the fuel inside the profiles. Statuses of limit switches are converted to logical states using an analogue-to-digital converter, and then they are transmitted via radio transmitter. The states are also presented in a LED display installed directly on the gauge. The measurement system indicates filling levels together with sound information about a low fuel level in the bin.

The presented bulk solid fuel level sensor consists of aluminium profiles connected together using connecting pins. Each of the elements is able to adjust positioning angle of the profiles in relation to one another. The profiles are hinged together, which allows them to accommodate easily to a cross-section of a bucket of fuel feeder. A component - aluminium profile - it is a profile with its cross-section in a shape of a "C" letter with the extended profiled side arms that make a connecting element. Each component is equipped with a limit switch located in its centre part which, at the time of filling up the bin, collapses and closes a circuit and switches on a LED indicator that shows in this way a corresponding level of bin filling up. Start position of the limit switch is open (an expansion spring holds a flap of switch in the open position), and it is being closed while it is covered with bulk solid fuel. At the top part of the device, there is a bent element made of aluminium that is used to suspend the gauge on a wall of feeder bucket. This element has fittingly shaped walls with holes, in which LEDs can be located in an amount that corresponds to the number of components. The bent component can also be equipped with a transmitter that allows sending a signal of filling state of the bin to an external receiver.

The invention acc. to the invention is distinguished by simplicity, easy-to- mount and versatility. Used system of bending the device that operates on a principle of chain, allows the user to place easily the device inside a fuel bin with a feeder, or to use it as a measuring element in other type of containers with any capacity. An easy change in length of measuring element allows you to adapt easily the gauge to a depth of bucket.

The object of the invention is presented in an embodiment in the drawings, where: Fig. 1 shows the device in an axonometric view with the device located inside a straight wall container; Fig. 2 illustrates the device in cross-section view, where the device is placed inside a straight wall container; Fig. 3 shows the device in a plan view with the device located inside the straight wall container; Fig. 4 shows the device in axonometric view with device located inside the container of rounded walls; Fig. 5 shows the device in cross-section with the device placed inside the container of rounded walls, Fig. 6 shows the device in a plan view with device located inside the container of rounded walls; Fig. 7 presents the same device in axonometric, front and side views; Fig. 8 illustrates a component of the device; Fig. 9 shows the component of the device with mounted limit switch; Fig. 10 presents the device component - a transmitter and a set of LEDs to indicate the filling level of the tank; Fig. 11 illustrates the possibilities of changing the device angle in a side view.

The gauge according to the presented invention consists of aluminium profiles [1] with a C-shaped cross-section with extended, profiled, side arms that form a connecting element. Components [A] are connected together using mounting pins [2]. The components [A], thanks to a loose connection with mounting pins [2] are able to adjust a positioning angle of the profiles with respect to one another. The profiles are hinged together, which allows them to accommodate/fit easily to a cross-section of furnace chamber [3] with a fuel feeder. Each component [A] is equipped with an aluminium profile [1] and a limit switch [4] which, at the time of filling up the bin, collapses and closes a circuit and switches on a LED indicator [5] that shows in this way a corresponding level of bin filling up. Limit switch [4] is also equipped with a spring [9] that holds it in an open position. Each limit switch [4] is protected against soiling with bulk solid fuel with a lock in a form of a flat rod [9] fixed to a main profile [1]. On the first element of the device, there is a bent item [6] made of aluminium which is used to suspend the gauge on a wall of a bucket [3] and is connected with the rest of the components with mounting pins [2]. Bent item [6] is equipped with a transmitter [7] with an antenna [8] and a set of LEDs (5) indicating the filling level of the container.