Abstract: A device and method for sharpening a mower blade are provided, in which a mounting device for mounting a rotary blade having two opposite cutting edges to be sharpened, wherein the mounting device is capable of positioning the blade in a first fixed state and a second, axially pivoting state. One or more grinding head assemblies are each positioned on an opposite end of the blade, wherein the grinding head assemblies respectively grind the two opposite cutting edges to be sharpened. A control system controls movement of the two grinding head assemblies.

Abstract: Apparatus is provided for modifying an open draft hood furnace and its control system, to produce an induced draft furnace having increased efficiency. A blower located in the furnace exhaust stack is used to induce movement of air and combustion products into and through the draft hood. A flow-limiting orifice located in the exhaust stack upstream from the blower causes a region of reduced pressure to exist downstream from the orifice. A pressure signal representative of the flow rate of exhaust stack gases is sensed on the downstream side of the orifice and is communicated by a conduit to a pressure switch connected to a gas valve, which together control gas to the burner. No gas is permitted to flow to the burner unless a predetermined reduced pressure level is achieved at the downstream side of the orifice. A small opening in the conduit permits a small flow of flushing air to enter the conduit.

Abstract: An induced draft combustion apparatus and its associated control system has a blower located in the exhaust stack or vent which is used to induce the movement of air and combustion products into, through and out of the combustion chamber. A flow-restricting orifice in the exhaust stack near the blower causes a region of higher pressure to exist upstream from the orifice with a region of lower pressure downstream from the orifice. An exhaust gas pressure signal representative of the exhaust gas volume flow rate is sensed on one side of the orifice and is fed back to a modulating gas valve which controls the outlet gas flow from the valve to be proportional to the magnitude of the exhaust gas volume flow rate. By controlling blower speeds and exhaust gas volume flow capacities as related to a selected orifice size, various firing rates for the furnace can be selected, from the design maximum down to various derated levels.

Abstract: A heating system of the type having a combustion chamber with a fuel burner, an inlet for combustion air and an exhaust stack is improved by adding a variable-speed induced draft blower, a flow-restricting stack orifice and a fuel valve sensitive to the exhaust gas flow rate through the stack orifice. The fuel valve turns on at a first predetermined exhaust gas flow rate and turns off at a second predetermined exhaust gas flow rate, which is lower than the first predetermined rate. The fuel valve also supplies fuel at a rate proportional to the exhaust gas flow rate. Sensing of the differential pressure across the stack orifice is used to determine the exhaust gas flow rate.

Abstract: An apron for use by persons working with precious metals, particles of which are dispersed as work is performed, comprises a sheet of combustible material having particle-trapping capabilities and means for fastening the sheet of material to the upper body of a person whereby particles dispersed come into contact with the sheet of material and are trapped. A method for recovery of precious metal particles produced by persons working with precious metal alloys comprises the steps of trapping the precious metal particles on the sheet of combustible material worn by the person working with the precious metal alloys, burning the sheet of combustible material containing the entrapped metal particles to produce an incinerated mass and refining the incinerated mass to separate and purify the constituents of the precious metal alloys.