US1825761A - Method of heating fluids in a spinning column and apparatus used in connection therewith - Google Patents

Description

Oct. 6, 1931.

Filed Feb.

c. w. STRATFORD METHOD OF HEATING FLUIDS IN A SPINNING COLUMN AND APPARATUS USED IN CONNECTION THEREWITH 2 Sheets-Sheet l IN VENT maria WalmiZJk k MW f A TT ORNE Y Oct. 6, 1931.

c. w STRATFORD 1,825,761 METHOD OF HEATING FLUIDS IN A SPINNING COLUMN AND APPARATUS USED IN CONNECTION THEREWITH I Filed Feb. 1928 2 Sheets-Sheet 2 IN VEN TOR Carlas h alcoii JZmZ/bm A TT RNE Y Patented Qchfi, 1931 A 2 UNITED STATES PATENT-.OFFICE.

cHARL swALco'r'r srm'rronn, or OAKLAND, CALIFORNIA METHOD OF HEATING FLUIDS IN A SPINNING COLUMN AND APPARATUS USED IN CONNECTION THEREWITH Application filed February 2, 1928. Serial No. 51,850.

This invention relates to improvements in a spinning liquid heaterand refers more particularly to a method for spinning liquid at high rotative velocity at its vperlpheral surface, and simultaneously moving the center in an axial flow, whereby the local circulation and mechanical circulation set up by mechanical force, transmit more rapidly the heat to the liquid.

Figure '1 is a side elevational v ew, with parts of the heater in section, show ng a convection surface and furnace settlng for a complete heating unit.

Figure 2 is a top view of the cylindrical heater shown in Figure 1. D

- Figure 3 is an enlarged composite sect onal view of the heater taken along the hnes A-A and B-B in Figure 2-.

Referring to the drawings, a furnace setting 1, is divided centrally by a partition 2 forming a compartment 3 and a compartment 4. The compartment 4 is divided by a brldge wall 5, on one side of which is a bank of tubes 6. Within the compartment 4, is positioned a tube or cylinder 7, having a head 8,1 n which is formed a volute 8a. This volute termmates in a flanged connection to which a return bend 9 is connected, the opposite end of the flanged return bend being connected to the top flange of the head 8.

The bank of tubes has an inlet supply pipe 10 and an insulated transfer line 11, connected to the discharge of the'tube bank and communicating with a flanged connection into the return bend 8, at a point above the center of the cylindrical heater.

The tube bank 6, and the cylindrical heating tube 7 are heated by fuel supplied through a fuel supply pipe 10a, by meansof which either liquid or powdered fuel is 1njected into the cylindrical compartment 4 and caused to travel in a spiral downward course in the direction shown by the arrows, passing out from the bottom of the chamber, after whirling about the tube 7 through the transfer duct 11, thence upward over the bridge wall 5 and downwardly again over the tube bank 6. After passing over the tube 6, the gases are discharged through the flue 12 to a stack or heat exchanging devices, not shown.

The head 8 is bolted by a flange connection to the upper flange of the cylinder or tube heater; Inside of the outer casing or tube 7 is a tube of smaller diameter numbered 13.

This inner tube is directly connected to the return bend 9, atthe top, by a gasketed screw joint and terminates at the bottom in an open ended tube just above the bottom ofthe larger tube. Connected to the bottom of the larger tube 7 by a flange joint held together by bolts 14:, is a lowerbearing support member for the shaft 15, at the bottom of which is mounted the rotor or turbine wheel 16. At the ends of the turbine Wheel, are mounted thin spiral vanes 17, which impart to the liquid its rotative spin. A bottom casing 18 encloses a motor diagrammatically shown in Figure 1, at 19, and a stuffing box enclosure 20. The stuffing box may be taken up from the outside by means of a hand wheel 21. The mechanism which permits the tightening of the stuffing box forms no part of the present invention. Thecentral or inner cylinder 13 is held at the bottom by means of supports 22 and below these supports are curved stationary vanes 23 which convert the straight line flow of the liquid, passing downwardly through the inner cylinder, into primary rotation set up by the curved stationary vanes 23 before the final rotative acceleration is im parted by the rotor or turbine blades 17 The liquid is charged to the heater through the pipe 10 and circulates through the inner cylinder 13. The liquid passes downwardly through the inner cylinder in straight-line flow. At the bottom of the inner cylinder the flow is reversed by the shape of the lower extremity of the heating cylinder and is given a primary rotative movement by the curved stationary vanes 23.

Afterpassing these vanes the liquid is picked up by the vanes 0f.the turbine spinner or rotor, traveling at high velocity, and is given a rapid rotative spin. The rotative spin and the centrifugal force imparted to the liquid, as well as the upward movement caused by liquid supplied in the central c linder, produce a s iral movement of the iquid in the interme iate annular s ace between the innerand outer shells 13 an 17, this spiral movement having a relatively small pitch and resulting in a slow upward movement while the rotative spin is at high velocit The rapid movement of the, liquid over t e heating surface, effects an eflicient heat exchange with proper combustion. A transfer rate has been obtained ranging from 100,000 to 300,000 B. t. u.s per square foot of heat exchanging surface per hour. The s inning of the 011 also prevents the accumu ation of polymerized or carbonaceous matter upon the inner surface of the chamber of the heating tube when liquid oil is being treated.

It will be noted that the joints by means of which the lower or upper heads are connected to the heating tube, are entirely outside of the heating zone, thus eliminating difliculties from this source. From the to head or .volute 8a there is taken off liquid t rough the withdrawal line 24. Vapor is taken off from the cylinder throu h the pipe 25 which withdraws the vapor rom a more central point from the cylinder. The separation produced by centrifugal force of the spinning liquid, causes the liquid material to cling to the outer portion of the cylinder while the vapor accumulates centrally of the cylinder.

After receiving its high rotative spin from the turbine or rotor blades 17, the liquid moves upwardly in a spiral of small progression and pitch, until it arrives at the top of the cylinder or to the head where a portion of the li' uid and the vapors is withdrawn, as suggeste ll, the remaining portion is directed through the return bend 9 and is fed back into the central or inner tube and is recycled with the incomin li uid charged to the heatin tube or cham er y means of the pipe 11.

lhe liquid take-off volute formed in the head 8, converts the rotative spin of the liquid into pressure and delivers the liquid through the return bend 9, of the vertical inner tube 13, back to the rotors or spinners thus saving a large percent of energy. The redirecting of the liquid by means of this loop connection or return end, materially decreases the work necessitated by the lower turbine or rotor.

The spinning energy is utilized to withdraw fluid from the spinning body and also recirculate the fluid in an axial down-flow column which is the supply feed for the spinners and spinning body in the annular space betiween the inner cylinder andthe outer cyllIl er.

The heatin of a spinning liquid cylinder is obviously t e most satisfactory manner to heat a liquid column as the most dense liquid is projected to the outside of the cylinder by centrifugal force and this outer film or layer is in a form which is most susceptible to the transmission of'heat to the liquid column. The vapor which is less susceptible to the heating action, accumulates in the center of the column where the lower temperatures subsist. The heating being applied to the cylindrical container is transmitted therethrough and to the rapidly spinning cylinder within.

Besides furnishing a most eificient heater, the construction affords the use of optimum combustion conditions as the rapid removal of heat permits the firing of the space surrounding the cylinder at a very rapid and intense rate without deterioration of the metal or brickwork of the furnace.

The outer cylindrical heatin surface receives not only convection heat 0 the combustible gases but the radiant heat reflected from the surrounding surfaces of the furnace zone, the furnace being preferably circular in form ofl'ers radiant heat projected directly upon the surface of the heating cylinder.

(1) The spinning liquid cylinder and furnace are shown ositioned vertically but the design contemp ates a metal heating tube placed in the axis of a circular combustion chamber arranged horizontally. The inlet for components of combustion is through a volute and the outlet for the combustion gases from the furnace is also through a volute, as described in my copending application. In this way, combustion gases are introduced into the circular furnace at a high lineal velocity which results in their spinning at approximately 1100 R. P. M. Within the con1- bustion chambers.

The liquid to be heated is introduced into the heatin tube. The feed plus liquid contained wit in the heating tube is rotated by a turbine type spinner to a peripheral velocity of approximately 90 feet per second or 1350 R. M.

The conception of this heater is founded on belief that high velocity travel of gas on one side of a heat transmitting diaphragm and liquid moving at high velocity on the other will result in unusual heat transfer rates.

(2) The pur ose of a heater of this description is to etermine the maximum rate of heat transfer possible between combustion gases and a liquid. The principal purpose is to develop a heater of the lowest cost per unit of heating capacity. The object of spinning the gas within the combustion chamber is to wipe the surface of the heating tube at approximately 77 ft. per second to promote heat transfer by convection. Rotation of the combustion gases throws the cooled gas to the outside and the hottest gas near the axis the circular combustion in direct contact with heatin tube. Eflicient radiant transfer through t e metal tube is promoted by its axial arrangement within chamber. Spinning of the metal tube the liquid over the surface of the li 111d film has for object the lowering temperature so far aspossible, whic results in maintenance of the highest possible temerature, difference between heat source and lq lll id to be heated.

he spinning liquid also results in throwing the colder portion of the liquid to the heated transfer surface and the hotter portion to the center of the spinning liquid. When the heating tube is allowed to operate not entirely filled with liquid but covered on the inner surface with a liquid tube of say 1 inch thickness, control is had of the volume of liquid in the system being heated. Under such conditions, approximately 60 sq. ft. of free liquid evaporative surface is exposed for freeing of vapors. and vapor promotes, at least to some degree, the separation of entrained liquid from the vapor- The liquid-free vapor may thus be withdrawn from the core of thg spinning liquid tube. This heater, used for evaporation of high boiling point hydrocarbons should be particularly applicable to high vacuum. Since all of the latent heat could be supplied, terminal temperatures required for a given vaporization would be lowest and thus avoid thermal decomposition.

(3) From experience, a circular furnaceof this description should not be made shorter than 15 feet. The net volume of the circular furnace has been designed for a release, In terms of approximately 40,000 B. t. u. per hour per cubic foot of total furnace volume. This rate of release is conservative. Since we have already attained a transfer to oil of over 87,000 B. t. u. per square foot of projected area per hour, it hasbeen assumed in the design of this furnace that 100,000 B. t. u.s per square foot per hour could easily be reached. With the'fired area of the metal tube presenting 60 square feet the capacity of furnace should easily be 6,000,000 B. t. u.s per hour heat input to oil. On water, 300,000 B. t. u.s per square foot per hour should be possible.

The net I. D. of the furnace is 4% feet, which gives a very short distance for radiant heat to travel from the hot face of the fire brick lining to the refrigerating surface of the heatin tube, consequently this face will probably oat at a temperature of not much in excess of 2000. With this temperature of the fire brick facing, it seemed rational to make facing only 4 inches thick, backed up with 4 inches of Silocel. To reduce cost of furnace construction, the wall of the masonry has been enclosed within a steel case. Temperature of steel case should not exceed 250 degrees F.

The spinning of the liquid It is hoped to attain a flame burst tempera ture of between 3600 and4000 and a terminal temperature of combustion gases from furnace of n t over 1400. In order to attain unusual y high flame burst temperatures, it is advisable to feed combustion with air at at least 500 F. A special heater for this furnace has been designed on the same rotative principle as the furnace itself which should deliver air to the burner at 500, and release the combustion gases at atemperature of not over No stack will be necessary since the whole combustion system is under pressure, impressed by the cold air fan, of 8 inches of water.

(4) This furnace may be applied to the vacuum distillation of lubricating oils or the vaporization of any type of crude oil. This type of furnace might have wide application as a steam generator.

(5) This heater is expected to show unusual values in terms of (a) low capital investment per million B. t. u. of heatercapacity, (b) high thermal efiiciency, (a) high service factor and (d) a very low cost of maintenance and'operation. I

By utilizing the turbine type of liquid spinner a maximum of mechanical energy exnded will be recoverable in high transfer rates with least loss by turbulence such as occurs in the pipe still tube elements and return bends. When the inside'of the'heating tube has been machined, ground and polished, it

canbe given a thin polished coating of the -.elling at high rotative velocity around the fluid cylinder.

2. A method of heating fluids comprising the steps of imparting high rotative velocity to said fluids imparting a relatively slower axial movement to the fluid mass, subjecting the fluid body to radiant and convection heat, converting the spinning energy into straight line movement and pressure, diverting a portionof the fluid from the cylinder and redirecting the remainder into an axial column and thence to the spinning body.

3. A method of heating fluids comprising the steps of imparting high rotative velocity to a continuous fluid cylinder, said fluid having a relatively slow axial movement, subjecting the spinning liquid body to radiant and convection heat and utilizing the spinning energy to withdraw fluid from the spin ning body and to circulate the fluid in a linioa eal, axial flow in a reverse direction to the axial flow of the spinning mass, and applying additional fluid to the axial column.

4. A method of heating fluids comprising the steps of mechanically applying a hi h rotative spin to a cylinder of liquid an subjecting the spinning li uid to radiant and convection heat applie to the exterior of the cylinder, converting the spinning energy Y 10 into straight line movement and pressure,

diverting a portion of the fluid from the cylinder and redirecting the remainder into an axial column and thence to the spinning body.

5. An apparatus for heating fluids comprising a cylindrical container, 9. cylinder of less diameter within the container, a return pipe connecting the annular space of the outs1 e cylinder with the inner cylinder, a drawoff line connected to the periphery of the g0 outer container and an inlet for supplying fluid to the inner cylinder, a means near the bottom of the cylinders for imparting rotative spinning to liquid in the annular space between the cylinders, and means for externally heating the outer cylinder. CHARLES WALCOTT STRATFORD.

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