US3111935A

US3111935A - Heater

Info

Publication number: US3111935A
Application number: US62486A
Authority: US
Inventors: Frederick A Loebel
Original assignee: Cleaver Brooks Co
Current assignee: Cleaver Brooks Co
Priority date: 1960-10-13
Filing date: 1960-10-13
Publication date: 1963-11-26
Anticipated expiration: 1980-11-26

Description

F. A. LOEBEL- Nov. 26, 1963 HEATER 2 Sheets-Sheet 1 Filed Oct. 13, 1960 Nov. 26, 1963 F. A. LOEBEL 3,111,935

HEATER 2 Sheets-Sheet 2 Filed 001;. 13, 1960 United States Patent 3,111,935 HEATER Frederick A. Loebel, Milwaukee, Wis., assignon to Cleaver-Brooks Company, a corporation of Wisconsin Filed Oct. 13, 1960, Ser. No. 62,486 2 Claims. (Cl. 122-33) This invention relates to a heater for viscous fluids, such as asphalt, which tend to decompose when heated in direct fired heaters.

It is a general object of the invention to provide a new and improved heater of the type described.

A more specific object is to provide a new and improved heater of the type described including an outer shell, an inner furnace within the shell, heat exchanger conduit means disposed around the furnace in the space between the furnace and the shell for conducting fluid to be heated longitudinally and circumferentially through the shell, and means for circulating heat transfer liquid in a predetermined path in the shell in heat transfer relationship with the furnace and the conduit means.

Another object is to provide a new and improved heater of the type described including a hot gas flue connected with the furnace adjacent one end thereof, encircling the furnace spirally and connected with an exhaust opening.

A further object is to provide a new and improved heater of the type described, including baflie means associated with the heat exchanger conduit means providing a predetermined path for circulation of the heat transfer liquid, and impeller means for circulating the liquid.

It is also an object of the invention to provide a new and improved heater of the character mentioned including a heat exchanger in the form of a combined conduit means and baflle means in which the conduit means provides for circulation of the fluid to be heated longitudinally and circumferentially through the shell, and the baflle means defines a predetermined path for circulation of heat transfer liquid in heat exchange relationship with the furnace and the conduits.

Other objects and advantages will become readily apparent from the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a side elevational view, partly in section, illustrating a heater embodying the principles of the present invention;

FIG. 2 is a fragmentary sectional view taken at about the line 22 of FIG. 1; and

FIG. 3 is a fragmentary sectional view taken at about the line 3-3 of FIG. 1.

While an illustrative embodiment of the invention is shown in the drawings and will be described in detail herein, the invention is susceptible of embodiment in many different forms, and it should be understood that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

The purpose of the apparatus of this invention is to heat viscous fluids which tend to decompose when heated in direct fired heaters. Decomposition results when the fluid remains in contact, even for short periods of time, with extremely hot metal, such as the metal surfaces of a fire tube or combustion chamber and hot gas flues. The present heater is designed specifically for heating asphalt, though the principles of the invention are not limited to this utility. Use is made of oil as an intermediate heat transfer fluid. The heat transfer oil is circulated over the metal surfaces of the combustion chamber and hot gas flue preferably at velocities exceeding 3 feet per second in order to control the heat exchange. The oil is preferably circulated by means of a propeller type pump, to

"ice

also contact conduit means providing a tortuous path for conducting the fluid to be heated, such as asphalt, through the heater.

Referring to the drawings in greater detail, and particularly FIG. 1, the heater preferably includes an outer shell 20 which may be cylindrical and which may be insulated as illustrated at 21. Centrally disposed within the shell 21 is a cylindrical furnace as at 22 spaced from the walls of the outer shell and providing a combustion chamber 23. At the right end as viewed in FIG. 1, the furnace is closed by an end wall 24, and at the left end is provided with refractory material as shown at 25. The refractory material is formed with a centrally disposed opening as at 26 in which there is positioned a burner structure 27. The burner structure may be properly provided with fuel supply and ignition control means in any conventional or other suitable manner. A burner tube 30 in which the burner structure is positioned, opens at the left end into a hollow end cap or closure member 31 to which combustion air is supplied by means of a fan as at 33 suitably driven by a motor as at 34. The insulated outer shell may be suitably supported on skids or the like as illustrated at 38.

The products of combustion pass from the combustion chamber 23 to a hot gas flue 32 connected to the furnace as at 33-, adjacent the right end thereof, spirally encircling the furnace toward the left end and opening to a chamber 35 having an exhaust opening in communication with an exhaust stack as at 36.

Positioned concentrically around the cylindrical furnace 22, in spaced relation between the furnace and the shell 23, is a heat exchanger generally designated preferably in the form of a combined conduit means and baffle means, the conduit means for conducting the fluid to be heated, such as asphalt, in tortuous paths longitudinally and circinnferentially through the heater, and the baffle means providing a determined path for circulation of heat exchange liquid through the heater in heat exchange relationship with the furnace 22, the flue 32 and the conduit means for the fluid to be heated. The heat exchanger includes a cylindrical baflle 42 concentric around the furnace 22 and spaced between the furnace and the outer shell 20. Adjacent the right end as viewed in FIG. 1, the member 42 has secured thereto an annular frusto-conic closure member as at 43 provided with a central opening as 44. The members 42 and 43, secured together suitably as by welding, may be supported in the outer shell 20 by any suitable means.

A propeller or impeller 45 is positioned in the central opening 44 and secured on a drive shaft 46 so that when rotated, heat transfer fluid is drawn into the propeller from the right end of the heater through a guide means 46a and pumped or propelled outwardly toward the left as viewed in FIG. 1. The pump drive shaft 46 may be provided with suitable pulley means as at 47 connected by belt means 48 to pulley means 43 on the shaft of a drive motor 50*. Provision is thus made for circulation of the heat transfer liquid in a predetermined path determined by the baflle members 42 and 43, including movement of the heat transfer liquid to the left as viewed in FIG. 1, through the annular space between the furnace 22 and a cylindrical baflle 42, in heat exchange relationship with the furnace 22 and the spiral hot gas flue 32. At the left end of the heater, the heat transfer liquid passes radially outwardly around the cylindrical baffle and toward the right end of the heater, in heat exchange relationship with the tubes for conducting asphalt through the heater, and back to the pump 45.

An annular series of horizontally disposed tubes 52 is arranged concentrically around the cylindrical bafie 42. Opposite ends of the tubes 52 are connected respectively to headers or manifolds 53 and 54-, in the form of annu- 3 lar tubular elements of rectangular cross section. An inlet fitting 55 and an outlet fitting 56 communicate with the header 54.

Baffles or dividers are positioned in the header 54 at angularly spaced positions as illustrated at 58, 59, 69 and 61. In the header 5'3, battles are positioned as illustrated at 63, 64 and 65. This efiectively divides the tubes 52 into six angularly spaced groups, so that fluid from the inlet 55 flows back and forth in the tubes in a tortuouspath to the outlet 56, flowing longitudinally to the left in FIG. 1 through three groups of tubes and longitudinally toward the right in FIG. 1 through three groups of tubes. It will be understood that the adjacent inlet 55 and outlet 56 are separated by the

baflies

58 and 63. The first group of tubes is positioned between the battles 58 and 59, the fluid flowing to the left in FIG. 1 through this group of tubes. The second group of tubes is positioned between the baflie 59 in the header 54 and the baflie 65 in the header 53, the fluid flowing toward the right in FIG. 1 through this group of tubes. The third group of tubes occurs between the baffle 65 in the header 53 and the baffle 60 in the header 54, the fluid flowing toward the left in FIG. 1 through this group of tubes. Continuing in this fashion, it will be understood that the fluid to be heated makes six passes back and forth longitudinally through the heater and circumferentially around the annular series of tubes to the outlet 56, while at the same time heat transfer oil is circulated through the shell 20 in heat exchange relationship with the furnace, the flue 32 and the tubes 52.

The header 54 and the annular closure member 43 may be relatively braced by angularly spaced braces in the form of triangular plates as at 68 suitably secured to both the closure member and the header as by welding, for example.

In order to provide for expansion of the heat exchange liquid in the shell 20 during operation of the burner, the chamber within the shell 20* is connected by a conduit 69 to an expansion tank 70 suitably supported above the insulated shell 20.

I claim:

1. In a compact heater for viscous fluids which tend to decompose when heated in direct fired heaters, a generally cylindrical outer shell of relatively large diameter, a generally cylindrical furnace tube of relatively large diameter centrally disposed in the outer shell and spaced therefrom, thereby providing a relatively thin annular space around the furnace in the shell for heat transfer liquid, a hot gas flue having a diameter about half the thickness of said annular space, connected to the furnace tube adjacent one end thereof and closely spirally encircling the furnace tube to the other end thereof, a unitary combined bafile and conduit means encircling the furnace in spaced relation between the furnace and the outer shell, including a cylindrical baflie closely encircling the flue providing a closed circulation path for the heat transfer liquid extending longitudinally substantially the entire length of the shell in one direction inside the baflie and in the opposite direction outside the bafllc, and including a single layer of tubular means of relatively small diameter supported on the baflle and extending substantially the entire length of the shell and arranged around the circumference of the baflle closely adjacent thereto and closely adjacent the outer shell for conducting fluid to be heated longitudinally throughout substantially the entire length of the shell and circumferentially substantially the entire circumference of the shell, and means for circulating heat transfer liquid in said closed circulation path in heat exchange relationship with the furnace, the flue and said tubular means.

2. A combination as defined in claim I, wherein said tubular means comprises an annular series of closely adjacent tubes, an annular tubular header on the cylindrical baflle at each end of the tubes each connected to the adjacent tube ends, an inlet fitting connected to one header, an outlet fitting connected to one header, and dividers in the headers grouping the tubes and providing a flow path for fluid to be heated from the inlet fitting longitudinally back and forth through the tubes, around the headers and to the outlet fitting.

References Cited in the file of this patent UNITED STATES PATENTS 1,980,424 Morgan Nov. 13, 1934 2,055,949 Sharp Sept. 29, 1936 2,582,134 Kimmell et a1 Jan. 8, 1952 2,656,821 Ray Oct. 27, 1953 2,924,203 Loebel Feb. 9, 1960 FOREIGN PATENTS 717,542 Great Britain Oct. 27, 1954

Claims

1. IN A COMPACT HEATER FOR VISCOUS FLUIDS WHICH TEND TO DECOMPOSE WHEN HEATED IN DIRECT FIRED HEATERS, A GENERALLY CYLINDRICAL OUTER SHELL OF RELATIVELY LARGE DIAMETER, A GENERALLY CYLINDRICAL FURNACE TUBE OF RELATIVELY LARGE DIAMETER CENTRALLY DISPOSED IN THE OUTER SHELL AND SPACED THEREFROM, THEREBY PROVIDING A RELATIVELY THIN ANNULAR SPACE AROUND THE FURNACE IN THE SHELL FOR HEAT TRANSFER LIQUID, A HOT GAS FLUE HAVING A DIAMETER ABOUT HALF THE THICKNESS OF SAID ANNULAR SPACE, CONNECTED TO THE FURNACE TUBE ADJACENT ONE END THEREOF AND CLOSELY SPIRALLY ENCIRCLING THE FURNACE TUBE TO THE OTHER END THEREOF, A UNITARY COMBINED BAFFLE AND CONDUIT MEANS ENCIRCLING THE FURNACE IN SPACED RELATION BETWEEN THE FURNACE AND THE OUTER SHELL, INCLUDING A CYLINDRICAL BAFFLE CLOSELY ENCIRCLING THE FLUE PROVIDING A CLOSED CIRCULATION PATH FOR THE HEAT TRANSFER LIQUID EXTENDING LONGITUDINALLY SUBSTANTIALLY THE ENTIRE LENGTH OF THE SHELL IN ONE DIRECTION INSIDE THE BAFFLE AND IN THE OPPOSITE DIRECTION OUTSIDE THE BAFFLE, AND INCLUDING A SINGLE LAYER OF TUBULAR MEANS OF RELATIVELY SMALL DIAMETER SUPPORTED ON THE BAFFLE AND EXTENDING SUBSTANTIALLY THE ENTIRE LENGTH OF THE SHELL AND ARRANGED AROUND THE CIRCUMFERENCE OF THE BAFFLE CLOSELY ADJACENT THERETO AND CLOSELY ADJACENT THE OUTER SHELL FOR CONDUCTING FLUID TO BE HEATED LONGITUDINALLY THROUGHOUT SUBSTANTIALLY THE ENTIRE LENGTH OF THE SHELL AND CIRCUMFERENTIALLY SUBSTANTIALLY THE ENTIRE CIRCUMFERENCE OF THE SHELL, AND MEANS FOR CIRCULATING HEAT TRANSFER LIQUID IN SAID CLOSED CIRCULATION PATH IN HEAT EXCHANGE RELATIONSHIP WITH THE FURNACE, THE FLUE AND SAID TUBULAR MEANS.