CH351282A - Evaporator device - Google Patents

Description

Device 6vaporateur The present invention relates to an evaporator device, in particular for a boiler. This device is characterized in that it comprises an evaporator tube intended to receive a liquid to be vaporized, said tube enclosing a coaxial hysficoidal ramp, in the axis of which there is provided a passage communicating with the space comprised between turns successive sections of said ramp and intended for the evacuation of steam, and in that it further comprises an orifice for the admission of the liquid to be vaporized into said tube.

The appended drawing shows, by way of example, several embodiments of the object of the invention. fig. 1 represents, in partially cut elevation, the upper part of the first form of execution.

Figs. 2 to 5 show in enlarged cross-section several variants of a detail of this embodiment.

fig. 6 represents, in partially cut elevation, the second form of execution.

Figs. 7 and 8 are enlarged views in perspective and in cross-section of a detail of the second embodiment.

fig. 9 is a perspective view of a variant of the same detail.

fig. 10 is a schematic half-section, perpendicular to Faxe of FIG. 9.

fig. 11 shows in axial section part of the third form of execution.

fig. 12 shows, in partial sectional elevation, the fourth form of execution.

fig. 13 represents in vertical section the fifth form of execution.

fig. 14 is a section through XIV-XIV of fig. 13, scale enlarged. Figs. 15, 16 and 17 are partial axial sections on an enlarged scale of said embodiment.

Figs. 18, 19 and 20 are respectively sections by XVIII-XVIII, XIX-XIX, XX-XX of fig. 17.

fig. 21 is a section through XXI-XXI of fig. 20.

The evaporator device represents in FIG. 1 comprises a cylindrical evaporator tube, traversed from bottom to top in the direction of the arrows F by a mixture of water and steam. A hot fluid circulates in the direction of arrow G inside a coaxial sheath <I>b,</I> surrounding the evaporator tube <I>a.</I>

A cylindrical conduit c is placed axially inside the evaporator tube a. This duct bears on its outer surface a strip of sheet metal rolled up in a helicoidal ramp, with progressively variable pitch, d. The volutes of Ph61ice are arranged obliquely, that is to say that they are inclined with respect to a plane perpendicular to the axis of the duct c, so as to constitute sorts RTI ID="0001.0267"WI="19 " HE="3" LX="1646" LY="2022"> of funnels dopt the opening is directed towards Faval. The presence of a propeller causes the mixture of water and steam circulating in the direction of the arrows F to be animated by a movement of gyration, and the centrifugal force acting on the water projects it outwards, while the vapor collects near the edge of the tube.

Between the various volutes of the propeller d, there are slots e in the wall of the duct c, which allow the steam to pass inside the body c, and to reach the place of use via the pipe f. station.

You can see at the upper part of the tube a gutter collecting water which may still remain in the mixture. It sends it back through a tube h inside the tube a, upstream of the duct c. The end <I>i</I> of the tube <I>h</I> has a slightly flared shape, so as to obtain, thanks to the movement of the evaporating interior fluid, a suction effect which automatically ensures the flow of the water contained in the tube h.

Instead of passing the first tube h outside the evaporator tube a, an can first pass it inside the evaporator device in hl, as an 1'a represented in phantom in FIG. 1.

The slots e made in the first body of the duct c are simple slots as seen in FIG. 2.

Alternatively, the wall of the duct c can be raised slightly to form lips j, as seen in FIG. 3, so as to accentuate the outward projection of the mixture of water and steam circulating in the direction <B>of,</B> the arrow H and to make sure that, at the same time, the steam passes through slots e. The lips j can even be turned over in the form of gutters k, as seen in fig. 4, so that the capture and separation of water are even better ensured. Finally, one can also arrange, at the height of the slots e, small deflecting surfaces 1, interesting all the height of the slot, and having the effect of deflecting the water towards the outside, all by creating with the wall of the duct c, Venturi tubes at the height of the slots e which complete the Separation effect.

To deconcentrate the water present in the first tube a to reduce its content of salts or other residues, the first evaporator tube a contains near the orifice of the return tube h, a tube whose flared orifice captures a part of 1 the water present and sent through a tube n to the outside of the tube where a tap o, schematically represented, makes it possible to purge a certain quantity of this highly concentrated water, which is replaced by a supply of water new at all points of the circuit.

On the volutes of helix d, slots (not shown) can also be made, arranged along the radii of this helix, and which have the effect of accentuating the separation of water and steam in the same way as the slots e made in the cylindrical duct c. The lips of these slots in the propeller tend to push the water upstream as the steam passes, and travels directly to the vertical slots e.

A p-tube is intended to evacuate a systematic excess of the liquid towards the outside, for example towards a balloon in order to ensure an automatic adjustment of the liquid supply.

The embodiment further comprises a passage (not shown) for the admission of feed water into the tube a.

In the embodiment shown in FIG. 6, an axial steam duct c, arranged inside a tube a, has on its periphery a mid-coidal ramp d, of constant pitch, extending over the entire height of the central cylindrical duct c and whose first edge comes into contact with the inner wall of the tube a. The latter is located in a current of hot fluid circulating in the direction of the arrow G outside the tube, inside an envelope b.

The water to be vaporized, introduced by a pump q, under pressure at the base of the tube a, is then subjected, due to the propeller d, to a gyration movement in the interval comprised between the tube a and the duct c. The fluid circulates in the direction of arrow H between two turns of propeller d. This movement of gyration of the mixture of water and vapor causes that, by the strong centrifugal force, the water is applied to the internal wall of the tube a, while the vapor remains closer to the faxe and passes through the slots e made in the wall of the duct c, to escape in the direction of the arrow F via the upper part of the duct c.

The edges of the slots e are folded outwards so as to form flaps 11 which, as seen in FIG. 10, are directed against the rotating movement H of the mixture of water and steam, so as to capture the steam which circulates around the tube c.

In a variant represented in FIG. 7, these slits are replaced by pipes r whose opening r1 is also as seen in fig. 8, directed against the rotating movement H, to capture the steam. The pipes r are located immediately below each turn, in the region where the most vapor is formed.

The mixture of water and steam rising at the upper part of the pipe c passes through a water and steam separator s known in itself, formed by two discs at right angles, and the water separated at the top of the pipe. this separator s is captured at s1 and returned partly to the outside by the pipe p and partly to the inside by the pipe hl which emerges at the base of the tube a, where it mixes again with the water entering the tube. Similarly, at the upper part of the tube <I>a</I> there is a pipe <I>t</I> with a bee-shaped opening which captures any residual water that may remain at this location and sends it back through the pipe hl to the base of the tube a.

In the first RTI ID="0002.0550" WI="5" HE="4" LX="1325" LY="1913"> case where the evaporator device would have to take inclinations on the vertical, being able to reach for example 30, it is important that the steam rising in the central duct c cannot escape through the slots made between the turns of the propeller. To this end, the embodiment shown in FIG. 11 comprises inside the duct c a helix surface u, each turn of which has a trapezoidal section, and which forms, inside the duct c, a series of nozzles forcing the steam to rise in the first direction of the axis of the tube along arrow F. As regards the parts not shown, this form of execution is similar to the previous ones.

In the embodiment shown in FIG. 12, a helically wound metal strip v affects for each turn a frustoconical shape v1, and the base of each turn is widened in the form of a disc v2, to come against the internal wall of the tube a. In this way, as seen in FIG. 12 in cross-section at the lower part, each turn of the Band v takes the shape of a hat cap, with roughly flat edges. The advantage of this arrangement, which is of a more harmonious realization, is that the successive cone trunks v1, partially embedded in each other, constitute between them suction nozzles of the Giffard type which prevent, on the one hand, the water from dripping. easily enter through these nozzles and, on the other hand, allow better suction of the steam by the steam jet coming from the lower part.

The preferred embodiment, which is shown in Figs. 13 to 21, is intended to be mounted vertically in parallel in a recuperation boiler, inside a sheath b through which hot gases pass. The evaporator device consists of a cylindrical tube inside which there is a helical ramp d wound on an internal tubular conduit c. The water to be vaporized arrives at the lower part through a collector 4 in the interval between the tubes a and c where the propeller d is located.

The gyration of the mixture causes the separation of the water from the steam, the steam rising in the axis of the tube c, where it is channeled by tubes u arranged end to end in the duct c, and whose external diameter is less than the internal diameter of the conduit c. The lower end of each of the tubes u is flared to form a seal with the condwit c, and the upper end of the tubes u is tapered into a truncated cone to form a nozzle. The tubes u are partially fitted into each other, over the entire height of the evaporator head. The steam finally reaches a water and steam separator s, placed at the upper part. From 1a, the vapor is finally collected in an upper manifold 1.

The hot fluid intended to transform the water into steam arrives at the upper part through a collector 2, to which is connected the sheath b which surrounds the entire device, and which is assembled at the lower part with a collector 3 serving to the evacuation of the hot fluid.

The sheath b is corrugated at b1 over a certain portion of its height, so as to absorb the forces due to the differences in expansion between it and the tube a and to avoid the transmission of these forces to the welds of the collectors 2 and 3.

RTI ID="0003.0279" WI="6" HE="4"LX="334" LY="2169"> The two tubes a and b must not have weak points likely to tear under the effect of these efforts, which implies a certain thickness of these tubes for the diameter adopted.

At the upper part of the device, the water remaining in the mixture of water and steam which runs between the tubes b and c is brought back by a tube h1, undulating at its base at h2, at the lower part of the device. , to be returned to the inside of tube c, from where it passes through the openings made in said tube c, towards the outside, in the interval comprised between tubes a and c where the helical ramp d is located. The lower part of the device thus functions as an economizer and vaporization begins at a certain height inside the tubes. The water-steam mixture operates under the effect of the helical ramp d. At the upper part which functions as a superheater, part of the water which may remain, instead of being recirculated, may be withdrawn through a tangential opening, leading to a pipe fitted with a needle p1 allowing the evacuation of this water (fig. 14).

The water recirculation pipes hi and the evacuation pipes p are connected, by tangential openings offset in height, to the space between the tubes a and c, as seen in FIG. 14, so that the first gyration movement of the water (in the direction of the arrow 1) facilitates the evacuation of said water towards the tubes h1 and p.

The tube a carries on the outside diametral longitudinal fins 5, which can be corrugated, which increase the heat exchange surface between the tube a and the hot fluid circulating in the space between the tubes <1. >a</I> and<I>b,</I> on the height which separates the first collector 2 from the collector 3 (fig. 16).

As seen in fig. 15, the tube passes through, at the lower part, the hot fluid evacuation manifold 3, and a bead 6, fashioned on this tube <I>a,</I> allows welding at 7 said tube <I>a</I> on the first manifold 3. The same arrangement is adopted at the upper part for the crossing by the first tube a of the manifold 2 for the arrival of the hot fluid.

As seen in fig. 17, the first tube h1, which allows the return of the water, emerges at the lower part of the duct c which rises in the fax of the evaporator tube, and which is provided with RTI ID="0003.0556" WI="5" HE="4" LX="1594" LY="1549"> on its external surface of the helical ramp d.

This duct c is completely closed off in its lower part, below the tubes u, by a partition 12 and orifices 8 are practical below the duct c, to establish communication with the space comprised between the tubes <I>c and a</I> where the helical ramp is placed d. These orifices 8 have the shape shown in section in FIG. 18 so that the water or the mixture of water and steam circulating in the direction of the arrow F in the space between the tubes a and c, causes by suction the entrainment of the recirculated water which emerges. che of the openings 8 in the direction of the arrows G. 11 results from this that, the higher the flow of water circulating in the direction of the arrow F, the more the suction acts on the orifices 8 and a greater quantity of water is then recirculation. The device is self-regulating, sucking in more water when the steam flow is greater.

It will be noted that the lips of the openings 8 are in the opposite direction to the flaps j1 of the slots g' (fig. 19) which are directed against the gyration movement F of the mixture of water and steam, in the part of the tube a which functions as an evaporator, and capture the steam in the mixture of water and steam, as explained above. The supply water arrives through the collector 4 from where it rises in the space between the tubes <I>c and a.</I> The flow rate of this water is calibrated by a disc 9, in which are practiced radial notches 10 (Fig. 20) through which passes Feau.

fig. 21 shows, in section, the profile 11 of the bottom of these notches 10, which has the shape of a Venturi, so that the water rising in the direction of the arrow H, is injected into the interval between the two tubes < I>c and a.</I>

The evaporator devices described can also be applied to the vaporization of a liquid under the effect of a pressure variation, or under the effect of a mixture with another fluid.

Claims (7)

CLAIM Evaporator device, in particular for a boiler, characterized in that it comprises an evaporator tube (a) intended to receive a liquid to be vaporized, said tube enclosing a coaxial Micoxdale camp (d), in the part of which there is provided a passage communicating with the space comprised between successive turns of the said camp and intended for the evacuation of the vapour, and in that it further comprises an orifice (4) for the admission of the liquid to be vaporized into the said tube. 1. Device according to claim, intended to be mounted vertically in a recovery boiler, inside a duct (b) through which hot gases pass, and comprising from bottom to top an economizer tube, a zone vaporization zone and a superheating zone, characterized in that said passage is formed by a pipe having openings in its wall, Jans which are disposed end to end and coaxially, in the vaporization zone, at least two nozzle tubes (u) has the outer diameter being less than the inner diameter of said conduit, the lower end of each of said nozzle tubes (u) being flared to form a seal with said conduit, and the upper end being tapered into a truncated cone to form a nozzle. 2. Device according to sub-claim 1, comprising at its upper part a water and vapor separator(s), and an outer tube (hl) for returning the separated water to return this water to the base. of the device and mixes it with the feed water, characterized in that a partition (12) completely closes off the said pipe (c) below the nozzle tubes (u), in that the said outer tube opens into the the base of said duct, the latter comprising, between its base andRTI ID="0004.0275" WI="9" HE="4" LX="1163" LY="749"> said partition, orifices (8) to pass the separated water in the space occupied by the said helical camp. 3. Device according to sub-claim 1, characterized in that each of said openings has a leere (j1) projecting into said space and oriented against the first direction of rotation (F) of the liquid circulating in said space (fig. 19 ). 4. Device according to sub-claim 2, characterized in that each of said orifices has a slight projection in said space and oriented in the first direction of rotation (F) of the liquid circulating in said space (fig. 18). 5. Device according to sub-claim 1, characterized in that a feed water flow rate calibration disc (9) is arranged transversely between the evaporator tube and said duct, at the lower part of said tube, said disc with notches (10) (fig. 20). 6. Device according to sub-claim 5, characterized in that said notches have a constriction (11) forming Venturi (fig. 21). 7. Device according to sub-claims 3, 4 and 6.