US3762466A

US3762466A - Static stirrer apparatus and process

Info

Publication number: US3762466A
Application number: US00156302A
Authority: US
Inventors: H Bhasin
Original assignee: Cenco Inc
Current assignee: Cenco Inc
Priority date: 1971-06-24
Filing date: 1971-06-24
Publication date: 1973-10-02
Anticipated expiration: 1990-10-02

Abstract

A static stirrer apparatus and process for use in agitating a fluid while elevating the temperature of the same fluid uniformly wherein a heating means for transferring heat to said fluid and elevating the temperature thereof is surrounded by a sleeve means providing a passageway for movement of fluid along the heating means, the sleeve means having an intake opening at its lower end, the fluid surrounding the sleeve means being transferred through the intake opening into the passageway and moved along the heating means through an outlet opening disposed in the upper portion of the sleeve means by convection. A static stirrer apparatus and process wherein the movement of fluid along the heating means within the sleeve means is effective to agitate the fluid surrounding and being heated by the heating means.

Description

United States Patent 1191 Bhasin I et.2,11973 l l STATIC STIRRER APPARATUS AND PROCESS [75] Inventor: Harish P. Blltasin, Chicago, Ill.

[73] Assignee: Ceneo Incorporated, Chicago, 111.

[22] Filed: June 24, 19711 [21] Appl. No.: 156,302

[52] US. Cl 165/108, 219/316, 219/523 [51] lnt. C1. 111051) 3/40 158] Field 01' Search 165/108, 128, 132; 219/319, 314, 322, 323, 523

[56] References Cited UNITED STATES PATENTS 3,614.386 10/1971 Hepplewhite 219/316 1379671 5/1921 Abtmeyer .7 219/523 Primary ExaminerWilliam F. O'Dea Assistant ExaminerWilliam C. Anderson Attorney-Robert E. Wagner [57] ABSTRACT A static stirrer apparatus and process for use in agitating a fluid while elevating the temperature of the same fluid uniformly wherein a heating means for transferring heat to said fluid and elevating the temperature thereof is surrounded by a sleeve means providing a passageway for movement of fluid along the heating means, the sleeve means having an intake opening at its lower end, the fluid surrounding the sleeve means being transferred through the intake opening into the passageway and moved along the heating means through an outlet opening disposed in the upper portion of the sleeve means by convection. A static stirrer apparatus and process wherein the movement of fluid along the heating means within the sleeve means is effective to agitate the fluid surrounding and being heated by the heating means.

2 Claims, 3 Drawing Figures STATIC STllRlREiR APPARATUS AND PROCESS BACKGROUND OF THE INVENTION This invention relates to a process and apparatus for thermodynamically agitating a fluid while elevating the temperature of said same fluid uniformly.

One of the most common methods of heating various types of fluids in both laboratory and industrial applications today is by placing a heating element within the receptacle or body containing such fluids and permitting this element to transfer heat to the fluid by conduction thereby eventually elevating the temperature of any given molecule of fluid by a certain minimum degree.

This method of conductive heating has the advantage of being both simple and inexpensive. There are major disadvantages to this method, however, and among these are the fact that heating elements used in this manner are subject to having certain minerals contained in the fluids in which they are immersed deposited on them in the course of heating such fluids. Such mineral deposition substantially decreases the useful life of these heating elements and necessitates continual replacement or cleaning of the elements in order to keep them in working order. The crust formed on the heating elements also reduces the efficient heating ability of such elements.

In addition, because of the fact that the heating element raises the temperature of the fluid in close proximity to it much faster and to a greater degree than fluid located at some distance from the element itself, heating of the fluid within the receptacle or body in which it is contained is accomplished in a non-uniform manner. This is undesirable because it sets up distinct thermal gradients throughout the fluid in the container, particularly between the fluid at the surface and the fluid in the bottom portion of the vessel. In this layering of thermal gradients, the temperature differential between the surface fluid and the bottom fluid is such that the surface fluid is at a highly elevated temperature in comparison with the bottom fluid. Likewise, the differential between the fluid surface temperature and the temperature of the surrounding atmosphere is also greater than it would be with uniform heating of the fluid and thus a greater heat loss is suffered than would be suffered if heating were uniformly accomplished.

- DESCRIPTION OF THE INVENTION The static stirrer apparatus and process of this invention involves the placing of a protective sleeve of novel configuration around a conventional heating element, this sleeve being effective to prevent the deposition of minerals on the heating element while at the same time providing for a uniform elevation of temperature throughout the fluid within which the heating element is placed, thus eliminating drastic temperature gradients within the fluid.

The apparatus and process of this invention causes this thermodynamic static stirring and uniform heating by drawing fluid having the lowest relative temperature of that contained in the receptacle or body into a passageway formed by the sleeve around the heating element, transferring this fluid along the operating heating element which raises the temperature of this fluid causing it to be convected out through openings in the top portion of the sleeve into the remainder of the fluid to be heated. This movement by the thermodynamic phenomenon of convection accomplishes static stirring of the fluid surrounding the heating element, also agitating or mixing the fluid in the receptacle without foaming. By acting on the lowest temperature fluid first, it also accomplishes a much more uniform elevation of temperature throughout the body of the fluid.

To effectively provide for the intake of low temperature fluid first, the present invention has at the lower end of the sleeve means an annular flange held in spaced relation above a plate by a plurality of support means. The flange and plate are of much greater diameter than the sleeve means so that fluid located at a distance from the heating element is drawn into contact with the heating element first.

The present invention is adaptable for use in either scientific or industrial heating procedures and may be used by simply changing its configuration to conform to the configuration of any type of heating element. In principle, this static stirrer is also adaptable for use in any size receptacle or body containing fluid, such as a beaker, flask, drum, tub, etc., where uniform heat distribution and elimination of thermal gradients are desirable.

This invention is also adaptable for use with a cooling element where uniform lowering of a temperature of a fluid is desired by merely inverting the sleeve means so that the intake flange is located near the top portion of the sleeve means.

Accordingly, it is an object of this invention to provide a process and apparatus for the elimination of min eral deposition on heating elements immersed in and operating in fluids.

It is a further object of this invention to provide a process and apparatus of the character described and having intake means of such dimension and located in such a manner that uniform heating of a body of fluid is accomplished and severe thermal gradients are eliminated.

It is a still further object of this invention to provide an apparatus and process combining thermodynamic static stirring designed to eliminate mineral deposition on a heating element while agitating or mixing fluid without foaming with uniform elevation of the temperature of the fluid being heated by such heating element.

It is also an object of this invention to provide an apparatus acting in combination with a conventional heating element to prevent deposition of minerals on such element and to produce uniform heating of the fluid surrounding such element.

These and other important objects of the present invention will become apparent from the following description taken in conjunction with the drawings illustrating a preferred embodiment wherein:

FIG. 11 is a perspective view of the static stirrer apparatus;

FIG. 2 is a vertical cross-sectional view of the static stirrer apparatus immersed in a receptacle containing a volume of fluid; and

FIG. 3 is an enlarged vertical cross-sectional view of the top portion of the static stirrer apparatus.

Referring now to the drawings and more particularly to FIG. l, the static stirrer apparatus lltl has a heater assembly Ill including a heating means or element 12 connected by plug 13 or other suitable means of connection to a source of electricity (not shown) or other suitable heat source.

The heating means 12 is surrounded by a sleeve means or tube 14 along the portion of its length which is to be immersed into the fluid to be heated. The sleeve means 14 is of hollow cylindrical configuration and opens at the lower end 15 of the sleeve means 14 to an intake opening 16 formed by an annular flange 18, which is connected to the lower end 15 of the sleeve means 14, and which extends outwardly beyond the circumference of the sleeve means 14. Below the annular flange 18 is a base plate 20 which is held in spaced relation from the annular flange 18 by support means or spacers 22 disposed between the base plate 20 and the annular flange 18.

The sleeve means 14 has disposed in its upper portion outlet openings or ports 24 through which the fluid within the sleeve means 14 is transferred out of the sleeve means 14 into the surrounding volume of fluid.

The top end 25 of the sleeve means 14 may be sealed to the atmosphere as shown in FIG. 3 by a sleeve cap seal 26 which is attached to the sleeve means 14 about the circumference of the sleeve means 14 and through the center of which is disposed the heating means 12. The sleeve cap seal 26 is then attached to the heating means 12 about the periphery of said heating means 12. The sleeve cap seal 26 thereby serves to not only support heating assembly 11 within the fluid to be heated but also to prevent excessive surface heat loss across the fluid-atmosphere interface in the sleeve means 14. Although use of the sleeve cap seal 26 is therefore preferred, such use is not necessary to the efficient operation of the static stirrer apparatus unless it is submerged.

In the operation of the static stirrer apparatus and process, the heating means 12 surrounded by sleeve means 14 is immersed in a fluid to be heated contained in a receptacle or container 28 as shown in FIG. 2. The lower end 15 of the sleeve means 14 is positioned near the bottom of the receptacle 28. The intake opening 16 formed by virtue of the large diameter annular flange l8 spaced above base plate 20 by support means 22 is effectively located near the corners of receptacle 28 which would ordinarily contain the volume of fluid last to be heated and, therefore, having the lowest relative temperature within receptacle 28 if heating were attempted to be accomplished by theremal conduction as it normally is accomplished. By use of the sleeve means 14 and the novel enlarged intake opening 16, however, the portion of fluid nearest the intake opening 16, that is, that in corners of receptacle 28, is drawn into opening 16 first when the heating means 12 begins to operate by the phenomenon of convection. In convection, the fluid contained initially in the passageway 30 formed along heating means 12 by the sleeve means 14 surrounding it is heated, thereby decreasing its density so that such less dense heated fluid moves upward along passageway 30, through the sleeve means 14 and a volume of fluid to be heated is drawn in through the intake opening 16 to take its place. As the volume of fluid to be heated is transferred from the intake opening 16 toward the passageway 30 and the heating element 12, its temperature is raised by operation of the heating means 12 which radiates heat throughout the area of the passageway along which the unheated volume of fluid travels. As its temperature is raised, the density of the fluid volume is similarly reduced and such volume of fluid thereby continues to move upward along the passageway 30. By the time a particular volume of fluid reaches the upper portion of the sleeve means 14, it has attained its maximum temperature and minimum density. This volume of fluid is then transferred into the portion of fluid surrounding the sleeve means 14 through outlet ports or openings 24 disposed in the upper portion of the sleeve means 14.

This upward movement of fluid along the passageway 30 by convection causes a stirring effect which prevents the deposition of minerals on the heating element 12.

While some heating of the body of the fluid contained in receptacle 28 takes place by convection, the primary method of heating remains that of conduction. However, the use of the intake opening 16 having a dimension greater than that of the sleeve means 14, so that the coldest, most dense portion of fluid in the receptacle 28 is drawn into the passageway 30 first, serves to substantially eliminate the drastic thermal gradients which result from heating a body of fluid by conduction alone, since the static stirrer apparatus and process acting on the principles of convection forces the coldest, densest fluid, located in the areas of the receptacle 28 ordinarily heated last under the conduction method, to be heated first.

The static stirrer apparatus may be constructed of any suitable material having a high thermal conductivity, subject to being easily shaped or formed, and resistant to corrosion by the fluids in which it is immersed, such as stainless steel, stainless steel alloys, aluminum, and other suitable metal alloys.

While the invention has been described in relation to a preferred embodiment thereof, it will be apparent to those skilled in the art that the structural details are capable of wide variation without departing from the principles of the invention.

I claim:

1. A static stirrer apparatus for use in agitating a fluid contained in a receptacle thermodynamically while elevating the temperature of said fluid uniformly, comprising heating means for transferring heat to said fluid and elevating the temperature thereof, sleeve means surrounding said heating means and providing a passageway for the movement of said fluid therealong, said sleeve means confining said fluid to said passageway to facilitate heat transfer between said heating means and said fluid, said sleeve means having a fluid inlet opening at its lower end and a plurality of fluid outlet openings disposed along an upper portion thereof, said fluid inlet opening including an annular flange formed at the lower end of said sleeve means and a base plate means held in spaced relation beneath said flange by support means, said flange and said base plate extending outwardly beyond the edge of said sleeve means a radial distance substantially greater than the diameter of said sleeve means and slightly less than the corresponding dimension of said receptacle to provide for movement of that portion of said fluid contained in said receptacle and disposed at a substantial distance from said heating means and having the relative coldest temperature in said receptacle into said passageway formed by said sleeve means first to assure uniform heating of all fluid contained in said receptacle, said plurality of fluid outlet openings providing a number of outlet means for movement of fluid out of the passageway formed by said sleeve means in response to the temperature gradient established in said fluid by heat transfer, the numing element and said sleeve means to thereby prevent excessive upward surface heat loss across the interface between the fluid confined in said passageway and the atmosphere.

Claims

1. A static stirrer apparatus for use in agitating a fluid contained in a receptacle thermodynamically while elevating the temperature of said fluid uniformly, comprising heating means for transferring heat to said fluid and elevating the temperature thereof, sleeve means surrounding said heating means and providing a passageway for the movement of said fluid therealong, said sleeve means confining said fluid to said passageway to facilitate heat transfer between said heating means and said fluid, said sleeve means having a fluid inlet opening at its lower end and a plurality of fluid outlet openings disposed along an upper portion thereof, said fluid inlet opening including an annular flange formed at the lower end of said sleeve means and a base plate means held in spaced relation beneath said flange by support means, said flange and said base plate extending outwardly beyond the edge of said sleeve means a radial distance substantially greater than the diameter of said sleeve means and slightly less than the corresponding dimension of said receptacle to provide for movement of that portion of said fluid contained in said receptacle and disposed at a substantial distance from said heating means and having the relative coldest temperature in said receptacle into said passageway formed by said sleeve means first to assure uniform heating of all fluid contained in said receptacle, said plurality of fluid outlet openings providing a number of outlet means for movement of fluid out of the passageway formed by said sleeve means in response to the temperature gradient established in said fluid by heat transfer, the number of openings being sufficient to agitate or mix the fluid contained in the receptacle without foaming.

2. The static stirrer apparatus of claim 1 including cap means covering the top end of said sleeve means, said cap means being hermetically sealed to said heating element and said sleeve means to thereby prevent excessive upward surface heat loss across the interface between the fluid confined in said passageway and the atmosphere.