Abstract: A feed forward control system maximizes combustion efficiency in a combustion system, by controlling the amount of excess air supplied to the burner. The feed forward control system includes flow sensors for sensing the flow of air and fuel to the burner. Based upon the fuel flow measurement, a digital computer determines the correct stoichiometric amount of combustion air required and the firing rate of the burner. Based upon the firing rate, the digital computer determines, from stored data in a look-up table, the necessary excess air required. Based upon the stoichiometric combustion air and the excess air, the computer determines the actual air that is required. This air required is then compared with the air flow measurement received by the digital computer. Based upon this comparison, an air trim actuator is driven by the computer until the required air flow is attained.

Abstract: A horizontal water filled vaporizer chamber is heated through the instrumentality of a horizontal combustion chamber extending through a lower portion of the vaporizer chamber. A first plenum inside the vaporizer chamber at a first end thereof receives combustion products from the chamber, and horizontal flues open to this first plenum carry these combustion products from it through the vaporizer chamber to a second plenum outside of the boiler where they are discharged up a stack. A plurality of vaporizer coils, each consisting of vertically spaced horizontal runs of pipe, extend from end to end in an upper portion of the vaporizer chamber. Each pair of adjacent pipe runs in each coil lie in a plane forming an acute angle with respect to a horizontal plane. Every vaporizer coil is connected inside the vaporizer chamber at its lower end to a liquid propane inlet header and at its upper end to a gaseous propane outlet header.

Abstract: A water bath vaporizer for converting liquid propane into gaseous propane includes a propane-carrying heat transfer pipe in the form of a helix immersed in a water bath in an insulated upright cylindrical water chamber. Multiple straight vertical flues are integral with a bottom plate and a top plate of the water chamber and are open through the water bath and the center of the helix to carry combustion products and heated air from a combustion chamber to a stack above. Liquid propane is introduced at the top of the helix and gaseous propane is removed from the bottom and is discharged vertically upwardly through a liquid cut-off float valve which prevents flow of liquid propane out of the vaporizer. A breather attachment includes a breather pipe having a first section extending outwardly from a top portion of the water chamber at a slight upward angle and having a vertical second section terminating in an upwardly opening outer end.