US3813211A

US3813211A - Cooler tubes for rotary kiln

Info

Publication number: US3813211A
Application number: US00288490A
Authority: US
Inventors: H Gommesen
Original assignee: SL Smith and Co
Current assignee: SL Smith and Co
Priority date: 1971-09-20
Filing date: 1972-09-13
Publication date: 1974-05-28
Anticipated expiration: 1991-05-28
Also published as: ZA726081B; AU4681572A; JPS4840824A; BR7206511D0; FR2154125A5; GB1306305A; AU468078B2; CA970561A; JPS5536907B2; SE385617B; DE2245995A1; ES406831A1; BE788998A; DE2245995C2; IT967573B

Abstract

An improved cooler tube construction for rotary kilns is disclosed which includes a conical internal surface located at the inlet end of each cooler tube. This conical surface acts to prevent back-spill and to advance material through the cooler tube.

Description

United States Patent [191 Gommesen 1 May 28, 1974 [541 COOLER TUBES FOR ROTARY KILN 2,904,522 9/1959 Bruff 432/117 5 l H 3,279,775 l0/l966 Ronbal [7 1 C n 3,372,915 3/1968 Jensen Denmark 3,556,495 H1971 Jensen [73] Assignee: S. L. Smith & C0., Cresskill, N,J 3,643,933 2/1972 McDonald 432/80 [22] Filed: Sept. 13, 1972 Primary Examiner-John J. Camby [21] Appl' 9 Assistant Examiner-Henry C. Yuen Attorney, Agent, or Firm-Pennie & Edmonds [30] Foreign Application Priority Data Sept. 20, 1971 Great Britain 43766/71 [52] U.S. Cl 432/80, 432/1 1634/1354 ABSTR C [51] Int. Cl. F27b 7/20 [58] Field of Search 432/103-106, An improved cooler tube construction for rotary kilns 432/80, 83, 115, 117, 26, 45; 34/134, 135, is disclosed which includes a conical internal surface 109, 127; 165/88 located at the inlet end of each cooler tube. This conical surface acts to prevent back-spill and to advance [56] 9 References Cited materialthrough the cooler tube. UNITED STATES PATENTS 828,555 8/1906 Krottmaurer 432/117 3 Claims, 4 Drawing Figures l COOLER TUBES FOR ROTARY KILN BACKGROUND OF THE INVENTION t openings and communicating chutes into each cooler tube as it passes through the lowermost point of its path of travel. Air is drawn or blown through the cooler tubes in a direction countercurrent to the hot material so as to cool it and subsequently enters the kiln through the outlet openings through which the hot material passes to the cooler tubes via the chutes. This preheated air is then utilized to support combustion within the kiln.

The kiln shell in rotary kilns of the type disclosed herein is generally mounted such that its axis of rotation is inclined upward in the direction opposite to the direction of material movement or flow within the kiln body. In one construction the cooler tubes extend alongside the kiln shell and are inclined upward in the direction in which material flows through the cooler tubes (i.e. in a direction opposite to the direction of material flow through the kiln shell.) Such cooler tubes are commonly known as uphill cooler tubes. In another construction, the cooler tubes extend away from the outlet end of the kiln shell and are inclined downward in the direction in which material flows through the cooler tubes (i.e., in the same direction as material flow through the kiln shell) in which case the cooler tubes extend-away from the outlet end of the kiln shell. The latter cooler tubes are commonly known as down-hill cooler tubes. In either construction the cooler tubes may be parallel or inclined at an angle to the axis of the kiln. Commonly the cooler tubes contain scoops, chains or other devices by which the material in them is urged towards their outlet ends, particularly with those constructions equipped with up-hill cooler tubes.

With rotary kiln constructions of the type described, there is often a tendency for some of the hot material entering each cooler tube when it is in its lower most position below the axis of the kiln to return to the kiln again when the cooler tube reaches its uppermost position above the kiln axis since, when in this latter position, the outlets of the communicating chutes are of course above their inlets. This return or backspill of material is very undesirable because it not only reduces output but also hinders the free passage of preheated air into the kiln.

Several kiln constructions have been proposed to eliminate or diminish back-spill. For relatively heavy, dustless or large particle material the problem of backspill has been to some extent overcome by providing oblique passages from the kiln to the cooler tubes rather than radial communicating chutes. In one construction the oblique passage is combined with a special form of the inlet end of the cooler tube. With this construction the part of the cooler tube at its inlet end which is opposite the mouth of the communicating chute is constituted by a part of the cylindrical wall of the tube and the part that'is-nearer the kiln shell is formed as a section of a cylinder the axis of which is so inclined to that of thetube as to provide a surface down which material in the'tube' may slide away from the outlet of the chute when the tube is above the kiln axis.

The present invention is specifically concerned with a new and improved construction of the inlet end of a cooler tube to substantially eliminate back-spill even when the charge in each cooler tube is larger than normal.

SUMMARY OF THE INVENTION According to theinvention the cooler tube and communicating chute are connected together in substantially tangential relationship and the end wall of each cooler tube adjacent the communicating chute includes a conical surface concave to the interior of the cooler tube with its apex at or near the junction point of the cooler tube and communicating chute. The conical surface is oriented in such a way that it advances incomming material away from the opening in the communicating chute. The conical surface also acts to prevent back-spill of material into the chute.

To further guard against back-spill, each chute of a kiln constructed according to this invention may be comprised of two or more straight pipes. At least two of these pipes are disposed in angular relationship with respect to each other. Thereby, a knee bend is formed in each chute which advantageously acts to trap backspilling material inadvertently entering the chute upon rotation of the kiln.

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF THE INVENTION With reference to FIG. I a rotary kiln 1 having a refractory lining 3 is shown for burning of a charge 2 of raw material (eg cement raw material) to clinker. At its outlet or lower end the kiln has a number of outlet openings 4 which communicate through chutes 5 with a corresponding number of cooler tubes 6 mounted with their axes substantially parallel to the axis of the kiln and arranged equiangularly around the kiln shell in a planetary fashion.

Each cooler tube comprises a cylindrical tube having an outlet 7 in one end of the tube and an inlet opening registering with the corresponding communicating chute 5. In the construction shown, the communicating chute 5 is comprised of two or more straight pipes ll, 12 and 13 which are joined together (e.g. by welding). Straight pipes 11 and 12 are connected together in angular relationship to thereby form a knee bend 14 pointing in the direction of rotation of the cooler tube indicated by the arrow in FIGS. 2 and 3. The cooled material discharged from the cooler tubes 6 is collected in a hopper 8 from which it is removed by conventional means well known in the art.

The inlet end of each cooler tube is closed by a conical surface 9 concave to the interior of the tube and having its apex 10 at or near the junction point of the communicating chute 5 and the cooler tube.

During operation material in the kiln rests substantially on one side of a central plane extending diametrically through the kiln. Usually, material is lifted within the kiln shell during rotation of same to form a cushion of material located substantially on one side of such a diametrical plane which is vertically oriented. During rotation the material processed in the kiln moves from the inlet end to the outlet end of the kiln shell where it flows into the cooler tubes through the communicating chutes. The material will start to spill over into the communicating chutes as they pass through the lowermost point in their circular path and slide gently through the communicating chute onto the cylindrical surface of the cooler tube.

As the tube moves upwards in its circular path, the material slides on the cylindrical surface of the cooler tube and is advanced in a direction away from the inlet end of the cooler tube by the conical surface 9 which acts to push the material forward in the cooler tube.

When the cooler tube has passsed its uppermost position, the cushion of material in the cooler tube, despite its general forward movement, may start to slide backwards because at this point the transporting effect of the conical surface is diminished. However, the tongue of the cushion of material will under normal circunstances be kept away from the opening in the communicating chute because of the barrier formed by the conical surface 9. Thus the conical surface acts to prevent back-spill.

Under certain conditions the charge in the cooler tube may be very high. For example it may be filled to 50 percent or more of its capacity. Some of the material may under such conditions reach the opening during the first of downward movement of the cooler tube, i.e. between its uppermost position and its position generally defined by a horizontal plane through the axis of the kiln. Any material which does then pass into the communicating chute will be trapped by the knee bend formed by the pipe sections 11 and 12 and thus prevented from reentering the kiln shell.

I claim:

1. In a rotary kiln having a plurality of cooler tubes mounted in planetary fashion around the outlet end of the kiln with the inlet end of each tube connected to the outlet end of the kiln by a communicating chute substantially tangentially disposed with respect to the cooler tube, the improvement which comprises said chute having a first pipe communicating with the outlet end of the kiln, and a second pipe in communicating angular relationship with the first pipe such that backspilling material is trapped and is prevented from reentering the kiln, and a conical wall forms at least a part of the inlet end of each cooler tube, said conical wall having a conical surface concave to the cooler tube, said conical surface being oriented so as to cooperate with the tangentially mounted communicating chute to advance material entering the cooler tube away from the opening in the communicating chute.

2. The improvement according to claim 1 wherein said conical surface has its apex approximately at the junction of the chute and the cooler tube to advance material entering the cooler tube away from the opening in the communicating chute in an improved manner.

3. The improvement according to claim 2 wherein said first and second pipes of said communicating chute are connected together to form a knee-bend pointing in the direction of rotation of the cooler tube.

1x33 UNITED s'mrus im'lm'l. OFFLCE r I O .L I CX'JR J. .U. .lL/x'flu O1" CORRLCTJON Patent No.; 3731731211- v v D t d May- 28, 1974 InventorCs) Hans Gommseri It is certified that error appears in the above iden I A tified t and that said Letters Patent are hereby corrected as shovm below ant 1. Under "Assignee" "S. L. Smith & Co. should read F. L Smidth & Co.-.

Signed and sealed this 24th day of September 1974.

(SEAL) Attest:

MCCOY M. GIBSON JR. c. MARSHALL 'DANN Attesting Officer Commissioner of Patents

Claims

1. In a rotary kiln having a plurality of cooler tubes mounted in planetary fashion around the outlet end of the kiln with the inlet end of each tube connected to the outlet end of the kiln by a communicating chute substantially tangentially disposed with respect to the cooler tube, the improvement which comprises said chute having a first pipe communicating with the outlet end of the kiln, and a second pipe in communicating angular relationship with the first pipe such that back-spilling material is trapped and is prevented from reentering the kiln, and a conical wall forms at least a part of the inlet end of each cooler tube, said conical wall having a conical surface concave to the cooler tube, said conical surface being oriented so as to cooperate with the tangentially mounted communicating chute to advance material entering the cooler tube away from the opening in the communicating chute.