A method and apparatus for dispensing a substance to a work area in which the method includes the steps of determining the quantity of the substance to be dispensed substantially evenly to the work area, calculating the rate of dispensing the substance to the work area for the quantity determined in the determining step to achieve substantially even dispensing, dispensing the substance to the work area at the calculated rate during movement over the work area, and adjusting the rate of dispensing at intervals during such movement to minimize error in such dispensing. The apparatus has a source of the substance to be dispensed, a dispensing mechanism for dispensing the substance from the source to a work area during movement thereover, a control mechanism operable to control the rate of dispensing the substance from the source, and a control system operable to detect the quantity of substance remaining in the source at intervals during movement over the work area and to adjust the rate of such dispensing so that the substance can be substantially evenly dispensed to said work area.

A portable fluid heating unit which may be used for supplying warm water to divers which includes a three stage heat exchange system wherein a fluid source, such as sea water, is initially heated as it passes through coils within the heating unit firebox and is subsequently heated in a first heat exchange chamber surrounding the firebox, after which, the fluid is heated by heat exchange with the exhaust gases from the firebox in a second heat exchange chamber. The temperature of the fluid is continuously regulated to insure that the heated fluid being conveyed to a diver is maintained at a substantially constant temperature.

An applicator mechanism for applying a layer of aggregate material on a ground surface comprising an adjustable bracket for mounting the applicator mechanism to a carrying device, a hopper attached to the mounting bracket having a first opening for receiving a supply of aggregate materials said hopper having a second opening for dispensing the aggregate material onto the ground surface, a first shaft attached to the hopper and in communication with the second opening having projections for spreading the aggregate material onto the ground surface through the second opening, a mechanism for driving the first shaft, a second shaft having at least one structure for interacting with the projections in order to control the size or amount of aggregate material exiting the hopper through use of a spring force that adjusts the tension applied to the paddle by way of a handle used to rotate the second shaft, and a mechanism for holding the tension handle in one of several predetermined positions.

A method and heating system for a hose and dispenser wand of a hot melt mix applicator uses a three phase heating element powered by a generator to heat the hose and wand to maintain hot melt mix material within the hose and wand in a flowable state. To selectively energize the generator to control heat input, the heating system has (1) a controller in communication with a temperature sensor carried by the hose or wand, and (2) an output in communication with a generator control input. The generator control input enables operation of the generator to be controlled by the controller for controlling heating of the hose and wand. The heating element is a cord having a first wire receiving a phase of the three phase current, a second wire receiving another phase of the current, and a third wire receiving another phase of the current, with the cord being wrapped about the hose and wand in a helical configuration. The generator preferably is a vehicle alternator modified so that it outputs three phase electrical power without requiring any voltage or current regulation. In a preferred method, the controller energizes the generator when the sensed temperature of the hot melt mix falls to or below a predetermined setpoint control temperature and deenergizes the generator when the sensed temperature rises to or above a predetermined setpoint control temperature.

An apparatus is provided for spreading aggregate material on ground. The apparatus includes a body 12, an engine 14 carried by the body, motive structure 18 powered by the engine to move the apparatus along the ground. A hopper 20 is associated with the body and is constructed and arranged to receive aggregate material from a source of aggregate material. Dispensing structure 24, associated with the hopper, is constructed and arranged to dispense aggregate material from the hopper to the ground. Wheel structure 30, carried by the body, is constructed and arranged to be movable between an inoperative position, wherein the motive structure is in a ground engaging position and the wheel structure is in a position so as not to engage the ground, and an operative position, wherein the wheel structure is in a ground engaging position and the motive structure is in a position so as not to engage the ground. A hitch structure 32, carried by the body, is constructed and arranged to be coupled to a vehicle so that the apparatus can be towed by the vehicle when the wheel structure is in the operative position thereof.