US1184546A - Apparatus for heating street-pavements. - Google Patents

Description

G. H. LUTZ.

APPARATUS FOR HEATING STREET PAVEMENTS.

APPLICATION FILED FEB. Il. 1916.

Patented May 23, 1916.

Glfviybneoo yGEORG-E H. LUTZ, OF CHIGAGO, ILLINOIS.

. .arraimrus ron HEATING STREET-Pavnmrs.

Specification of Letters Patent.

Patented May 23, 1916.

Application med Febipary 11, 191s. serial N o. 77,776.

To all whom t may concern.'

Be it known that I, .GEORGE H. LU'rz, a citizen of the United States, residing at Chicago, inthe county of Cook and State of Illinois, have invented 4certain new and useful Improvements in Apparatus for Heating Street-Pavements, of which the following is a specification.

This invention relates to an apparatus for continuously generating a relatively large body of heated air or equivalent heat-conveying medium, and discharging it in heating relation to a relatively large area of street surface in the form of an evenly distributed sheath evenly heated throughout, so that the heat treatment of the surface over which the apparatus is a plied at any given time will be uniform t roughout its area.

The apparatus is especially designed for use in heating street pavements as a preliminary s tep to removing the upper stratum of plastic paving material in the process of re-surfacing the street; or for heating the surface of stone pavements to render it re-I ceptive of the binder that is employed in the aplplicationof an asphalt surface to an eXisti g street-surface of stone. Apparatus heretofore employed for -these and similar purposes has been found objectionable for various reasons Apparatus in which the heating flame is applied directly to the surfaceis objectionable, because of the liabilityA of burning the material treated, and when used in connection with a heat-modifying means such as air inlets or blast-producing means, such apparatus has been objectionable because of the unequal distribution of the heating medium overthe surface to be heated.

The present invention seeks to improve the known apparatus. for heating street.

pavements by developing a `largevolume of i heating medium from a body ofair and fuel introduced conjointly into a combustion .chamber under conditions which insure not only an effective blast from the delivery end of the apparatus, with consequent suction of an ample volume of air and complete combustion of the fuel, but cause this combustion to take place at a point suiciently remote from the point of discharge, toinsure complete mixture of the air and products of combustion and uniform tempering of the resultant heat-conveying body before it reaches the discharge flue, so that substantially the same heating efect is developed throughout the area which the machine is adapted to cover.

In carrying out the invention, I employ an elongated combustion chamber having at one end a discharge flue provided with the usual distributing and confining hood which defines the area of treatment, and having at its opposite end, a large air intake flue extending for some distance back from the combustion chamber and having concentrically associated therewith, at its receiving end, a blast producer or blower and a fuel injector; these parts being arranged so thatl they not only bring in a large body 0f air under a considerable momentum, but mingle with the incoming air, an yannular stratum of blast medium, preferably steam subdivided into a number of jets, and a central jet of fuel mixture, preferably oil and steam.

The invention will be fully understood upon reference to the accompanying drawing, in which Figure 1 is a vertical longitudinal section of a typical form of apparatus embodying the several features of the invention, and Fig. 2 is a detail View of the combined blasting or air-injecting device and fuel feed jet.

1 represents a hood adapted to be superposed upon an area of street surface to be heated, in position which conines a heating medium in relation to the surface, and

2 is a supply flue for such hood. In orderto deliver to the' fl'ue 2, a highly fluid heatconveying medium under a sulicient blast' 'chamber 3 having at its end remote from the flue 2, a combined blast-developing and fuel-feeding intake 4. The intake 4: is constructed with an open outer end 5, so that the main volume of Huid entering it is atmospheric air, but it'is equipped with an annular blast-inducing blower 6 in the form of a steam conduit having jet openings presented longitudinally of the intake 4: and connected through suitably valved pipe 7 with a source of steam supply; and a concentric fuel atomizer and injector 8 of any suitable construction, such for instance as a fuel pipe 9 fed by suitably valved pipe 10, surrounded by a spaced jacket 11 in injector relation thereto and fed by the valved steam pipe 12. The axial dimension of the intake 4 isl sulicient to insure mixing and ignition of the fuel in the air and blast-inducing medium, so that by the time these elements reach the combustion chamber 3, combustion is proceeding violently, and by the time the resultant mixture of heated air and products of combustion reach the Hue 2, combustion `has substantially ceased and the elements are thoroughly mingled and tempered, so that they reach the hooded surface in the condition already referred to. The combustion chamber is preferably provided with a baiie wall 13; also with a Water jacket 14 provided with a steam dome 15 as an economical source of steam required for operating the apparatus.-

16 represents a connection through which to receive steam fr om an external source whenever it may be desired, as for instance when the .apparatus is being started up from a cold state.

apparatus constructedas above described not only obviates the diHiculties encountered with apparatuses heretofore constructed, but it affords a simple and effective means of developing the continuous supply of Huid medium required for heating surfaces. in work such as that referred to; the apparatus is at all times subject to convenient supervision and regulation; the blast-inducing element 6, which has proven a particular source of annoyance and loss of time when employed in the discharge Hue, is in its present relation not only where temporary stoppage of some of its jets does not adversely affect the uniformity of the discharged heating medium, but where its jets can readily be reached for cleaning and where theblower as a whole can be readily cleaned by opening a blow-0H' cock 17 at frequent intervals Without shutting down the apparatus. Moreover, this location of the blower at a point where it is protected i' rom the heat of the apparatus permits the use of a very much more eiicient blower and greatly lessens the .cost of maintaining the blowing element as compared with the location in the Hue 2, as heretofore proposed. The blast developed in the present machine imparts such momentum to the incoming charge that the expansion due to the heat of combustion Hnds its relief only toward the discharge end of the machine' and thus adds to the blast in the desired direction.

I claim 1. An apparatus for heat treatment of the surface material of roadways; said appa-v ratus comprising an air heating and conditioning chamber having at one end a discharge Hue and a distributing hood,1and, at its end remote from said discharge Hue, means for maintaining in said chamber, a body of air at high temperature, under sufficient pressure to forcibly expel 'the air and insure strong impingement of the hot air against the street surface beneath the hood; said means comprising an air intake Hue freely open at its outer end to atmosphere, a jet-injector discharging inwardly into said intake Hue and inducing therethrough a glingof the air and burning gases and being Y elongated between the intake and discharge Hues sufliciently to insure completion of combustion of the fuel and delivery of the air'to the hood without Hame.

2. An apparatus for heat treatmenti V'of roadways; said apparatus comprising an air heating and conditioning chamber having at one end a discharge Hue and a .distributing hood, and, at its end remote from said discharge Hue, means for maintaining in said chamber, a body of air at high temperature, under suflicient pressure to forcibly expel the air and insure strong impingement of the hot air against the street surface beneath the hood; said means comprising'an air intake Hue freely open at its. outer end to atmosphere, a steam jet injector discharging inwardly into said intake Hue and inducing therethrough a strong -blast of air, a steam generating chamber located in heat absorbing relation to the air conditioning chamber, and adapted to develop steam under pressure and supply it to the steam injector; and a liquid fuel atomizer and fuel injector also discharging inwardly into said intake Hue and maintaining in and delivering with said blast of air, burning gases sufficient to develop, throughout the body of air, the temperature required; the air intake and discharge Hues being of considerably smaller section than the conditioning chamber; the intake Hue having the capacity under the action of the blast to maintain an air supply largely in excess of that required for combustion, and the conditioning chamber being constructed to insure mingling of 5 the air and burning gases and being` elongated between the intake and discharge flues sufficiently to insure completion of combustion of the flie and delivery of the air to the hood Without ame.

The foregoing specification signed at 10 lVashington, District of olumbia, this 11th day of February, 1916. l

GEORGE H. LUTZ.

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