US2202034A - Well heater - Google Patents

Description

May 28, 1940. w. K. THOMAS WELL HEATER Filed June l, 1937 GNU/Muay Patented May 28, 1940 UNITED STATES wenn .earenr orrici:

6 Claims.

This invention relates in general to well heating devices, and more particularly has reference to a heater adapted to be lowered into a well or the like for the purpose of heating the same and assisting in the removal of foreign deposits on the walls thereof.

Particularly in connection with oil wells there is formed after a period of time a deposit of paraiiine or the like on the walls of the well and on the screen or strainer at the bottom of the Wall where such a structure is employed. This deposit of paraiine sooner or later becomes such as to obstruct the ow of the well and prevent it from producing the amount of fluid which it would otherwise be capable of producing.

It is an object of this invention to provide a device for supplying heat at a desired point or points within the well for the purpose of melt ing or softening the paraiine or other deposits and make possible their removal.

It is a further object of this invention to provide an improved heating device of the type set forth in which electrical heating elements will be employed and although protected in the greatest possible degree from damage by contact with foreign objects and from contact with the fluid inthe well, will be enabled to supply the maximum amount of heat to the well without themselves becoming overheated.

It is a further object of this invention to provide a heater of the type set forth in which the various heating elements may be removed and replaced with relative ease.

It is a further object of this invention to combine a device for supplying heat to the well with a means for mechanically removing the deposits therefrom either before or after the same has been heated.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawing, the same being by way of illustration and example, however, and not by way of limitation. This invention is to be limited only by the prior art and by the scope of the appended claims.

Referring now more in detail to the drawing,

Fig. 1 is a vertical cross section through a portion of a well showing in elevation therein a heater constructed in accordance with this invention.

Fig. 2 is a View partly in vertical cross section 'showing the details of the heater illustrated in Fig. 1.

Fig. 3 is an elevation of one of the heating elements of the heater shown in Figs. l and 2.

(Cl. 21S-33) Fig. 4 is a horizontal cross section taken along the line 4-4 of Fig. 2.

Fig. 5 is a similar View taken along the line 5--5 of Fig. 2. v

Fig. 6 is a View similar to Fig. 2 b1it`illustrat ing a modified form of heater.

Fig. 7 vis' a view similar to Fig. 4 and Fig. 5

`but taken along the line 'l-l of Fig. 6.

In Fig. l there is illustrated a section ofV a well casing l having a strainer or screen 2 adjacent the lower end thereof. Within this casing I there is suspended by means of a tubing 3 or the like a heater constructed in'accordance with this invention. To the collar i which is secured to the lower end o f the tubing 3 there is threadedly engaged the upper'tubular extension 5 of an elongated body 6 which is preferably `constructed of ycast iron or some similar material 'forming a relatively good conductor of heat. Communicating with the tubular section 5 is an 20 opening 'I which extends the entire length of the elongated body member 6, thus providing a passageway from the lower -end 'of this body member upwardly into the tubing '3. At intervals along its length the body member 5 is also provided with laterally extending openings B communicating with the passages through the interior of the body member 6 and opening to the exterior of this body member'.

The body member E intermediate the lateral passageways 8 is provided with a plurality of elongated socketsor grooves each of which is adapted to receivean elongated bar 9 of cast iron or similar material within which is completely imbeddeda U-shaped electric heater element l0 and aterminal Il at the upper end thereof.

It may be stated at' this point that the heater elements here employed may be purchased on 40 the open market and that'per se they form no part' of this invention. They are provided with 'aA highly heat conductive electrical Ainsulationand informing the elements 9 of cast iron these heater elements may be cast Within theelements l themselves, thus forming an absolute-protection against contact of the elements with any foreign objects which might damage them,and against Contact with the liquid within the well. However, the cast iron or the like which surrounds the elements is a highly heatconductive material, and the heat is thus readily conducted-away from the elements themselves so that they are not permitted to become Overheated as has been the case in previous constructions where in order l to secure proper electrical insulation heat insulating means have been employed.

The elements S are placed in position within the sockets in the body 6 and their upper terminals Il are connected with a cable or the like l2 which passes upwardly to the top of the well and is connected with a suitable source of electrical energy. Enclosing and forming a chamber about the upper ends of the elements 9 and about the connections li is a member i3 which might be termed a bonnet having its upper end if, hollowed out to provide a stuffing box surrounding the tubular portion 5 of the body and having its-lower end of substantially the same internal diametery as the upper end of the body. 'Within the stuffing box ld at the upper end of the bon-- net I3 is a suitable packing l5 adapted to he compressed by means of a gland lli so as to form a fluid-tight seal about the tubular portion t5 of the body. A bushing il' forms a seal about the cable I2 at the point where it passes through the bonnet I3 and upwardly to the surface of the well, and the space within the bonnet is adapted to be partially or completely filled with moulded electrical insulation of any one of a number of well known types.

Secured to the lower end of the bonnet and extending downwardly about the body and the elements carried thereby is a tubular member I9 forming a sheath about the body and having a coupling at its lower end for a purpose to he presently set forth. This member i9 has perforations 2l therethrough adapted to register with the openings 8 in the body of the heater so that uid may circulate up through the body and out these lateral openings, or vice versa.

Secured in the coupling 2li and extending downwardly therefrom is a short section of pipe 22 on the lower end of which are mounted one or more up-turned packing cups 23, so that upon upward movement of the heater these packing cups will drag upwardly along the walls of the casing l and tend to remove therefrom any foreign accumulations.

Referring now to the modification illustrated in Figs. 6 and '7, this form illustrates a unitary heater in which the heating elements are not separately removable. In this construction, a body 2li is formed about one or more heating ele ments 25 in such a manner as to leave the central portion of the body free, this central portion of the body being formed with an opening 25. Adjacent the upper end of the openings 2S there are provided a plurality oi lateral outlets 2'! so that uid may circulate up through the body. through the passageway 26 and out through the openings 21.

Threadedly engaged with the upper end of the body 24 is a bonnet 28 constructed in a manner similar to that illustrated in Fig. 2 and forining a closure about the connections 29 at the upper ends of the heater elements. A cable :ill passes from the connection 2Q out through the bushing 3! and upwardly into the top of the well. thus providing a means for transmitting energy to the heater element 24. The interior of this bonnet 2B is partially or wholly filled with a moulded electrical insulation 32 in much the same manner as that described in connection with Fig. 2. It is noted that in this instance the insulation is shown as forming a closure the upper end oi' the passage 26 through the body 2 so that circulation through the passage 2li will necessarily pass through the lateral opening 2'! and will not pass through or into the tubing above the heater element.

In View of the foregoing, it will be noted that a heater has been provided in the forni illusn trated in Fig. 2 in which the destruction of one or more of the heating elements will not necessitate a discarding of the heater, but that these elements may be removed and replaced singly so that the heater as a whole may go on in use. It is to be noted that the casting constituting the body ci the heater illustrated in Fig. 2 is a much more complicated and hence a much more expensive casting than the casting 9 in which the heating elements lil are imbedded. Thus, the replacement of the casting 9 is much less expensive than would be the replacement of the entire heater if this were necessary upon the burning out oi' one ci the heating elements. Further more, it is to be noted that the heating elements surrounded with bodies which will positively protect them against any outside destructive inuence, including the fluid` within which they operate, but that the protecting bodies are formed oi highly heat conductive material such that the heat will be conducted away from the and the elements not allowed to become over-heated. In this connection, it is to be noted that while cast iron is mentioned as a material which may be used for the body of the heater, any other suitable material having the desired characteristics of high heat conductivity and strength to protect the heating elements may be employed. This is also true ci the form illus trated in Fig. 6.

In addition to the foregoing, it is to be noted that the present invention nia-lies possible the ch'culation oi fluid through the heater and the carrying away ci the heat therefrom so that the heating elements are even less likely to become over-heated.

Furthermore, the applicant has provided a combination of a heater for loosening the de posits upon the walls of a well casing with a means for positively and mechanically removing these deposits.

It will thus be seen that a means has been provided for carrying out all the objects and advantages sought by this invention.

Having described my invention, I claim:

l. In a well heater, an elongated primary body ci highly heat conductive material having longitudinal laterally open sockets therein, secondary bodies of highly heat conductive material removably positioned within said sockets, respectively, and of a size to substantially cornpletely iill the same, and a U-Shaped electrical heater element molded into each of said secondary bodies.

2. In a well heater, an elongated primary body of highly heat conductive material having 1ongitudinal sockets therein, seconda-ry bodies of highly heat conductive material removably positioned within said sockets, respectively, and of a size to substantially completely ll the same, a Ushaped electric heater elementV completely emn bedded in each of said secondary bodies, said primary body having an yopening centrally thereof and extending from one end to the other and tubing connected to one end of said opening and extending upwardly from said body.

3. In a well heater, an elongated primary body oi highly heat conductive material having longitudinal sockets therein and a central opening therethrough, secondary bodies of highly heat conductive material removably positioned within said sockets, respectively, and of a size to substantially completely ll the same, a U-shaped electric heater element completely embedded in each of said secondary bodies, and a sheath about said primary and secondary bodies for retaining said secondary bodies in place in said socket, said primary body and said sheath having registering lateral openings communicating With the central opening through said primary body.

4. In a Well heater, a metal body having a passagevvay centrally thereof and lateral openings into said passageway, said body having laterally open grooves extending along its outer sides, metal bodies snugly and removably fitting said grooves, and insulated electrical heater element embedded in and snugly embraced by each oi said last mentioned metal bodies, and means for securing said last mentioned metal bodies in place in said grooves.

5. In a Well heater, a metal body having a passagevvay centrally thereof and lateral openings into said passageway, said body having laterally open grooves extending along its outer sides,

metal bodies snugly and removably iittingl said grooves, and insulated electrical heater element embedded in and snugly embraced by each of said last mentioned metal bodies, and means for securing said last mentioned metal bodies in place in said grooves, said lateral openings through said rst body being disposed between said grooves.

6. in a Well heater, an elongated body of highly heat conductive material having longitudinal soelets therein which sockets are open laterally with respect to said body throughout substantially their entire length and width, a secondary body of highly heat conductive material removably positioned Within and substantially completely filling each of said sockets respectively, oi said secondary bodies being removable in a lateral direction With respect to said elongated body and through the said lateral openings from said sockets, and an electrical heater element molded into each of said secondary bodies.

WILLAM K. THOMAS.

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