US2047459A

US2047459A - Surface condenser

Info

Publication number: US2047459A
Application number: US754110A
Authority: US
Inventors: Chamayou Benoit-Elie
Original assignee: Individual
Current assignee: Individual
Priority date: 1934-11-21
Filing date: 1934-11-21
Publication date: 1936-07-14
Anticipated expiration: 1953-07-14

Description

y 1936- BENCH-ELIE cHAMAYou 2,047,459

SURFACE CONDENSER Filed- Nov. 21, 1934 2 Sheets-Sheet l.

July 1.936- BENOlT-ELIE CHAMAYOU 2,047,459

SURFACE CONDENS ER Filed Nov. 21, 1954 2 Sheets-Sheet 2 Patented July 14, 1936 iTED STATES PATENT OFFICE SURFACE CONDENSER Application November 21, 1934, Serial No. 7 54,110

11 Claims.

The present invention relates to surface condensers of the kind wherein the steam is condensed in vacuo upon the outer surfaces of tubes through which circulates liquid, usually water,

of a temperature lower than that of the steam. The steam condenses upon the outer surfaces of the tubes and its heat, or rather the heat due to the condensation, passes through the metal of the tubes into the interior to be absorbed by the circulating liquid.

To be effective, the surface upon which condensation takes place should be maintained dry, as a coeflicient of the heat transmission of the steam to the cooling surface is a maximum if no layer of 15 low heat conductivity is interposed between the steam and the surface upon which the steam condenses. Now, water is an extremely bad heat conductor and therefore immediately a deposit of water is formed upon the tubes, it acts as an insulator.

It is therefore essential in order to produce a.

| condensation of high efliciency, to remove the condensed water as soon as possible after its formation, or take steps with a view to attaining a disposal or removal of the water by which the unfavourable effect and the extent of the contact of the water with the condensing surfaces is reduced as far as possible.

It has been suggested with this object in view,

to provide condensation apparatus with iron sheets or partitions placed at various altitudes between the tubes of the condenser. This solution is, however, expensive and not very effective. It has also been proposed to use arrangements of tubes in which the condensed water runs off in a tangential direction so that the streamof condensed water is directed into certain channels. In these arrangements the tubes are arranged above each other in sucha manner that water drops from the lowest point of the cross section of a tube, that is from the lower end of the vertical diameter of the tube, and then during its fall in a vertical direction, encounters or strikes tangentially an adjacent lower tube at the end of the horizontal diameter of the tube. Only that portion of the lower tube which is adjacent to the end of the horizontal diameter" is therefore wetted, whilst the remaining portion of the lower tube is not within the path of the flow of the condensed water.

This known arrangement has serious drawbacks. In the first instance this arrangement does not permit of a drop of liquid coming from above adhering or attaching itself to the lower v tube. As the drop of liquid is of a fairly substanpractically vertical, the impact of the drop upon 5.,

the lower tube cannot substantially reduce the velocity of its fall, and the drop will therefore not adhere or attach itself to the lower tube. The result is that practically the whole of the drop will rebound from the lower tube and be split into a 10 number of very small drops which will fall upon the upper portion of one of the tubes arranged underneath the lower tube. Therefore, the object of the arrangement, which is to remove further tubes from the the path of flow of the liquid, will 1.5

not be attained in practice. Moreover, in this arrangement, the descent of the drops can remain approximately vertical only if the velocity of the steam current arriving upon the tubes is zero or very small. In fact, however, the steam will, 2 owing to the existing arrangement of tubes, move in an oblique direction into the spaces separating the tubes. If the velocity of the steam current is fairly high, which is as a rule the case, the steam will, particularly in the upper parts of the con- 25 denser, deflect the dropping water from the vertical path and will cause the drops of water to move or jump in all directions.

Whilst it is very important that as great a portion as possible of the condensing surface be 30.

maintained dry, dryness of the surface on which condensation takes place is not the only condition to be fulfilled in order to attain a satisfactory efficiency of operation of a surface condenser. A further important condition is that the joints of 35 the tubes be as tight as possible so as to avoid in operation any mixing of the circulating water with the condensed water.

The present invention has for its object to provide means for ensuring a satisfactory efficiency 40 of working of a surface con-denser, and it therefore comprises also novel arrangements of the tubes aiming at reducing to a minimum the surface wetted by the fall of drops of condensed water and at avoiding any rebounding or scatter- 45 ing of the drops, and it also aims at avoiding any deflection of the drops due to the action of the currents of steam occurring in the condenser. The invention has also for its object to provide means for maintaining during the operation, com- 50 plete tightness of the condenser and avoiding any deformation due to expansion or contraction under the action of heat, which might alter the original arrangement of the tubes and thereby render that arrangement ineffective.

In the accompanying drawings Figure 1 is a diagrammatic view explaining the principle on which the improved arrangement of tubes according to the invention is based.

Figure 2 shows diagrammatically the arrangement of tubes in a surface condenser according to the invention, the drawings for instance showing the ends of the tubes in a header.

Figure 3 shows diagrammatically in sectional elevation, the manner of mounting the tubes with a view to avoiding any detrimental effects of deformation during the working.

Figures 4, 5, and 6 show modified modes of mounting the tubes.

According to the invention, the tubes are arranged relatively to each other in the manner explained in Figure 1. A drop of condensed Water formed at the bottom of the cross section of a tube a, falls upon the lower tube (11 which latter is located in such a manner that the middle point In of the falling drop of water is vertically above the centre of the horizontal radius of the tube. In other words, the falling drop of water meets the lower tube at a point b1 which lies substantially at the extremity of a radius including with the horizontal radius an angle of 60, the surface of impact of the drop upon the lower tube being substantially inclined at an angle of 30 to the horizontal as shown in the drawings. This result is attained by shifting in a horizontal direction the axes of the tubes a and (11 by a distance equal substantially to half of the radius of the tube. Experiments show that with this arrangement, the velocity of the drop after the impact, although not entirely destroyed, is sufiiciently reduced to avoid any rebounding of the water. Consequently the drop falling upon the tube a1 will fiow along the adjacent side of the tube a1 and will be re-formed at the bottom of the tube, that is at the lower end of the vertical diameter of the tube.

It will be understood that in practice it is not absolutely necessary that the drop of water should fall exactly upon that point of the tube at which the tangent includes an angle of 30 with the horizontal. Rebounding and splitting of the drop will be practically avoided even if the point of impact is moved from the above mentioned point either to the left or to the right through say 10. The zone included within the above described limits, is a zone in which the invention will work satisfactorily.

In order to remove the falling drops of water from the deflecting action of' the current of steam occurring in the condenser, it is proposed to make provision according to the invention, for the fiow of the condensed water and the flow of steam to be parallel to each other. With this object in view the tubes are arranged in substantially vertical rows, except that the tubes of one substantially vertical row are alternately shifted to the right and the left by a distance approximately equal to half the radius of the tube as explained with reference to Figure 1. Figure 1 shows three consecutive tubes a, a1, (12 of a vertical row, and the tubes are generally arranged in the manner shown in Figure 2.

On looking upon two adjacent vertical rows of tubes such as A and A1, it will be seen that adjacent tubes located in the same horizontal plane are all separated by the same horizontal distance :21.

With this arrangement a current of steam reaching the bundle of water tubes in the direction of arrows ,f, 1 (Figure 2) always finds between the vertical rows of tubes well defined channels through which it moves downwards, whilst penetration of the steam current between horizontal rows of tubes is practically impossible as it would necessitate a deflection of the steam current at an angle of It will also be seen that if the drops of water should have the tendency of moving away from the tubes or leaving the path which they are meant to follow, the steam current will tend to hold the water or move it back to the intended path rather than deflect the drops from their paths.

Figure 2 shows also that it is possible to provide Within the bundle of tubes spaces like B through which steam can arrive in considerable quantities and also spaces like D through which residual air of condensation can move slowly towards the suction side or sides of one or more air pumps or air ejectors. This arrangement also afiords the possibility of increasing the distance a: for the purpose of facilitating in the case of large bundles of tubes, deep penetration of the steam into the bundle of tubes.

In order to obtain by this arrangement a satisfactory operation along the whole length of the tubes, it is necessary to ensure that the relative position of the tubes within a bundle of tubes should remain unchanged so that the point of contact of a falling drop of water with the next lower tube should not change. The known provision of intermediate supporting sheets may assist in that direction, but if these supporting sheets are too numerous they interfere with the proper working of the condenser.

In all the condensers deformations of the tubes, namely, expansions and contractions occur owing to the fact that the tubes have not a free play. In practice, it is found that tubes undergo a deformation at their ends in all possible directions, namely, in the horizontal, vertical and oblique directions. In that case, the arrangements made with a view of directing the flow of the condensed water, will no longer work satisfactorily particularly commencing at a certain distance from the headers or the plates in which the water tubes are inserted.

The arrangements shown in Figures 3, 4, 5, and 6 have for their object to maintain along the whole length of the tube the mode of downward flow previously described with reference to Figures 1 and 2, by fixing from the start the possible ultimate deformations, expansions or contractions of the tubes. For this purpose it has been found sufiicient to arrange these deformations to take place in a certain predetermined plane, for instance, in the vertical plane by a suitable initial fixing of the tubes. By this means, it is possible to predetermine the possible molecular conditions occurring in the metal, by which the ultimate deformation is caused.

Figure 3 shows diagrammatically a condenser in which the improved mode of mounting a condenser tube has been applied to a single tube.

The header plates g and g1 and an intermediate supporting plate 92, are parallel to each other. The holes in the plates through which the tubes pass are bored at right angles to the plate, but the holes intended to receive the same tube are disposed along a straight line h, is, Z which is inclined with regard to the horizontal line h, p. 721, ki, 21 show the tube in position ready to be fixed in the plates. The mounting of the tube is therefore very simple as in ordinary condensers. h2, kg, 12 show the same tube after the tube has been actually secured in the plates and has,

by the operation of fixing: in the. plates, become somewhat curved or bent. It will be seen that the fixing of the tube in the plates has resulted in giving the tube the shape of a. sinusoid having two horizontal ends. This manner of mounting. therefore gives to all the tubes of: the condenser the same identical form and any deformation of the tubes which may occur afterwards during. operation, will take place in the: original plane of the tube as bent or curved during the fixingoperation.

Therefore, as soon as any tube expands during operation and therefore increases the curvature of the tube in the chosen plane, substantially the same bending will occur in connection with the adjacent upper or lower tube and consequently the aimed at fiow of condensed water will not be substantially altered by the deformation of the tubes. Practice showsthat in order to attain this result, it is sufficient to provide initially an inclination of 1 of the line h, k, l relatively to the horizontal line h, 11 (Figure 3). This manner of mounting moreover, provides a perfectly tight apparatus which will undergo with out any difiiculty or trouble the usual variations of temperature. Moreover, owing to the inclinationof the tubes relatively to the horizontal, emptying of the tube is facilitated whenever such emptying is necessary or useful.

The described manner of mounting the tubes may be applied to condensers of all dimensions. Figure 4 shows the manner of mounting applied to a condenser having no intermediate supports between the headers. Figure 5 shows the arrangement as applied to condeners having several intermediate supporting plates.

Tubes mounted in the above described manner, exert oblique reactions upon the header plates in which they are fixed. These reactions can, if desired, be balanced by changing the sense of inclination of the tube from row to row. For instance, as shown in Figure 6, all the tubes of one vertical row may be inclined in one direction, and all the tubes of the adjacent row may be inclined in the opposite direction.

I claim:

1. In a surface condenser having water tubes, an arrangement of tubes according to which superposed tubes are horizontally displaced so that the horizontal distance between the axes of the tubes is substantially equal to half the radius of a tube, whereby a drop of condensed water falling from the upper tube will reach the lower tube in the vicinity of a part at which the tangent is inclined substantially at an angle of 30 with regard to the horizontal.

2. A surface condenser in which water tubes are arranged substantially in vertical rows, the adjacent tubes of a vertical row being displaced horizontally alternately to the left and to the right by a distance substantially equal to half the radius of the tube, whereby a drop of condensate falling from any tube will strike the tube below it at a point where a tangent to the lower tube makes an angle of substantially 30 with the horizontal, the vertical rows of tubes being spaced apart so as to provide channels through which steam can move in directions parallel to the direction of the fall of the condensed water, substantially as described.

3. A surface condenser in which tubes are arranged substantially in vertical rows, adjacent tubes of a vertical row being alternately displaced horizontally relatively to each other by a distance substantially equal to half of the radius of a tube, whereby a drop. of condensate falling from any tube will strike the tube below it at a point. where a tangent to the lower tube makes an angle of substantially 30 with the horizontal, the vertical rows of tubes being spaced apart to provide channels for the movement of the steam, large clearance spaces being provided in the upper portion of the condenser for the arriving steam, and small clearance spaces being provided in the lower portion of the condenser for the air, substantially as described.

4. In a surface condenser of the tubular type, the combination of head plates having holes bored at right angles to the plates, tubes arranged substantially in vertical rows fixed in said headers, said tubes being fixed initially in the headers substantially at an angle of about 1 with regard to a line standing at right angles to said headers, the ends of the tubes being fixed in the holes of the headers, whereby the tubes have from the start an initial deformation in a definite plane; adjacent tubes of a vertical row' of tubes being horizontally displaced by a distance equal to half the radius of the tubes, the displacement being alternately to the left and to the right, substantially as described whereby a drop. of condensate, falling from any tube will strike the tube below it at a point where a tangent to the lower tube makes an angle of substantially 30 with the horizontal.

5. In a surface condenser having water tubes an arrangement of tubes according to which superposed tubes are horizontally displaced to such an extent that a drop of condensed water falling from the upper tube will fall upon the lower tube at a point at which the tangent is inclined at an angle of no more than 30 with regard to the horizontal.

6. A surface condenser in which water tubes are arranged substantially in vertical rows, adjacent tubes of a vertical row being displaced horizontally alternately to the left and to the right, the vertical rows of tubes being spaced apart so as to provide vertical channels through which steam can move vertically downwards between falling streams of condensed water, substantially as described.

7. A surface condenser in which water tubes are arranged substantially in vertical rows, adjacent tubes of a vertical row being displaced horizontally alternately to the left and to the right, the vertical rows of tubes being spaced apart so as to provide vertical channels through which steam can move vertically downwards between falling streams of condensed water, large clearance spaces being provided in the upper portion of the condenser for the arriving steam, and small clearance spaces being provided in the lower portion of the condenser for the air, substantially. as described.

8. In a surface condenser having water tubes, the sub-combination of: two parallel head plates having cylindrical holes bored at right angles to the plates; tubes arranged in vertical rows fixed at their ends in said headers, the centres of the holes corresponding to a tube being located on a straight line including an angle of about 1 with regard to a line standing at right angles to said headers, the ends of the tube being expanded into the holes of the headers, whereby the tubes have from the start an initial curvature in a definite plane, the direction of the inclination of a tube with regard to one header being opposite to the direction of inclination of the same tube with regard to the other header.

9. In a surface condenser having water tubes, the sub-combination of: two parallel head plates having holes bored at right angles to the plates; tubes arranged in vertical rows fixed at their ends in said headers; intermediate supporting plates substantially parallel to the headers and provided with holes through which said tubes pass; the centres of all the holes corresponding to a tube being located upon a straight line passing through the centres of the holes in which the ends of a tube are fixed, said straight line including an angle of about 1 with regard to a line standing at right angles to said headers; the ends of said tube being expanded into the holes of the headers, whereby said tubes have an initial undulating curvature in a definite plane.

10. In a surface condenser having water tubes, the sub-combination of two parallel head plates having cylindrical holes bored at right angles to the plates; tubes arranged in vertical rows fixed in said headers; the centres of the holes in the headers corresponding to a tube of one vertical row being located upon a straight line including an angle of about 1 with regard to a line standing at right angles to said headers; the centres of the holes corresponding to any tube in an adjacent vertical row of tubes being likewise 10- cated upon a straight line including the same angle with regard to a line standing at right angles to said headers but in the opposite direction; the ends of said tubes being expanded into the holes of the headers.

11. In a surface condenser having Water tubes, the sub-combination of: two parallel head plates having cylindrical holes bored at right angles to the plates; tubes arranged in vertical rows fixed in said headers; intermediate supporting plates for said tubes parallel to said headers and provided with holes for the passage of said tubes; the centres of the holes corresponding to a tube in a vertical row being located upon a straight line passing through the centres of the holes in the headers receiving said tubes, said straight line including an angle of about 1 with regard to a line standing at right angles to said headers; all the centres of the holes corresponding to a tube in an adjacent vertical row of tubes being 20 likewise located upon a straight line including the same angle but in the opposite direction with regard to a line standing at right angles to said headers, the ends of all said tubes being ex- 25 panded into the holes of the headers.

BENOIT-ELIE CHAMAYOU.