JPS5857201B2 - Evaporator - Google Patents

Description

[Detailed description of the invention] The present invention relates to a plate type evaporator.

In any type of evaporator, it is important to have good liquid distribution over the heating surface; if this is not sufficient, the product will burn due to lack of liquid coverage and the resulting build-up will be reduced. Depending on the item, cleaning may become necessary within a short period of time.

This is especially true at the outlet end of the heating surface where the flow rate of liquid is the lowest due to concentration, and the above point is particularly important since film type evaporators, which are different from natural circulation type, have a low flow rate.

Film-type evaporators are particularly applicable to temperature-sensitive liquids where short residence times have little effect on product quality.

If the concentration is high and therefore the flow rate of the final product or liquid is low, it is necessary to reflux a certain amount of product to the feed side of the evaporator to increase the flow rate over the heating surface sufficiently to prevent burning. There are many cases.

However, reflux increases the residence time in the evaporator and deteriorates the heat transfer efficiency, making it impossible to fully utilize the advantages of the film-type evaporator in this regard.

On the other hand, dividing the evaporation process into series stages minimizes the need for such reflux, increasing the liquid flow rate per unit width of the heat transfer surface and reducing the possibility of deposits.

The invention relates to this arrangement of the plates of a plate-type evaporator.

A plate-type evaporator has some plates, and each plate has corresponding holes in other plates to accommodate the heating medium (
Holes are provided forming an inlet and an outlet for the vapor (usually discharged as concentrate), an inlet for the feed liquid, and an outlet for the concentrate and vapor, respectively.

Each plate is then fitted with a gasket to use the alternating flow spaces between the plates as channels for the heating medium and feed liquid.

The evaporator is a falling film type.
(tip) or rising/falling film type (risin)
The present invention will be described below by taking a falling film type evaporator as an example.

In British Patent Specification No. 1425176, the inventor has disclosed that two groups of plates are provided by a partially closed plate with the supply liquid feed holes closed and the concentrate/vapor discharge holes partially closed.
one group of plates has its concentrate/vapor outlet divided into two channels and is equipped with a separating device at the end remote from the partially closed plate, one of the channels having the It communicates with the feed liquid flow area of one plate group and at the same time is blocked from communicating with the concentrate/vapor outlet of the other plate group by a partially closed plate, thereby allowing the concentration from the one plate group to flow. A plate-type evaporator is proposed in which the vapor and vapor are sent to the separation device and the concentrate is discharged, and only the vapor is returned from the other flow path and sent to the concentrate/steam outlet of the other plate group. did.

However, this return of vapor flow requires an external connection at each end of the concentrate vapor outlet.

That is, one is for a separator such as a cyclone, and the other is for the liquid removed from the separator.

The plate-type evaporator is mounted on the frame between the fixed head and the movable follower, so that the plates can be separated for cleaning and/or disassembly, so one of the two connections must be provided on the movable follower.

However, if the connection part is attached to the movable follower, it is necessary to release the connection part and at the same time move the related conduit out of the path of the movable follower, making the separation more difficult.

Furthermore, as described in the said British Patent Specification, although the connection to the gas-liquid separator is on a fixed head, the separator is mounted on a movable follower.

The present invention provides a partially closed plate having a group of plates disposed between a fixed head and a movable follower, the supply liquid supply hole being closed, and the concentrate and vapor discharge hole being partially closed. The concentrate/vapor outlet of the plate group on the fixed head side is divided into two channels, and one of these channels is communicated with the liquid flow space between the plate groups on the fixed head side. At the same time, the partially closed plate blocks communication with the concentrate/steam outlet from the other plate group, and the other flow path is communicated with the concentrate/steam outlet of the other plate group, and both A plate evaporator with flow channels extending to a common outlet and further comprising a separation device for removing concentrate and vapor from the other plate group before the vapors from both plate groups are mixed at said outlet. I will provide a.

The concentrate/steam outlet may be divided by a dividing bar extending transversely to the respective hole in each plate and having a gasket, or alternatively, the concentrate/steam outlet may be separated by a dividing bar having a gasket, or may be vented from the partially closed plate to the fixed head end. It may also be a dish extending along the outlet and supported as appropriate.

Incidentally, German Patent No. 2252802 discloses a plate-type evaporator in which the flow space between the plates is divided into two or more flow path areas, and each flow path area is provided with individual product/steam discharge holes. However, the present invention is particularly effective in connection with this type of evaporator if any or all of the above-mentioned discharge holes are partially divided.

That is, when two channels are provided in each plate, if one part of the concentrate/steam outlet is divided, there will be three stages of evaporation, and if part of both are divided, there will be four stages.

The invention will now be described with reference to illustrated embodiments.

FIG. 1 is a sectional view showing one end of a concentrate/steam outlet 1 in a plate-type evaporator.

Reference numeral 2 denotes a group of plates disposed between a fixed head 3 and a movable follower (not shown) forming a part of the frame of a conventional plate-type evaporator, and a gasket having a portion 4 defining the outlet 1. In addition, gasket portions 5 are alternately provided to separate the flow path of a heating medium such as steam from the discharge port 1.

The fact that the supply liquid flow path communicates with the discharge port 1 means that there is no dripping.

Reference numeral 6 denotes a barrier plate that further divides the plate group into two groups, and both of these plate groups preferably share a common steam.

Although it has a concentrate inlet, the liquid supply inlet is separated by a suitable hole in the barrier plate 6 as a blind hole.

The barrier plate 6 has an extension 7 that blocks a part of the outlet 1.
A dividing bar 8 and a gasket 9 are provided in the plate group between the barrier plate 6 and the head 3 in a direction transverse to the discharge port 1, so that the discharge port 1 is connected to two flow paths 1a.

Divide into 1b.

The head 3 is formed with a communication port 10 as in the conventional case, but the communication port 10 is provided with a dividing bar 11 that is connected to the dividing bar 8 in the discharge port 1 and the dividing bar 11. 1
1, a pan 12 extends for a predetermined length along a discharge pipe 13 connecting the discharge port 1 to a conventional gas-liquid separator (not shown).

Reference numeral 14 denotes a recess 14 formed below the dish body 12, and has a lip portion 15 and a liquid discharge connecting portion 16 erected on the downstream side.

In the above configuration, the first stage of evaporation proceeds within the plate group between the barrier plate 6 and the head 3, and the concentrate and vapor are transferred from the discharge pipe 13 through the flow path 1a of the discharge port 1 to the conventional cyclone. etc., to a gas-liquid separator (not shown).

The liquid from this gas-liquid separator is led as a feed liquid to the plate group on the left side of the barrier plate 6, and the concentrate and vapor from this plate group flow through the other channel 1b, so that the liquid is transferred to the recess 14. The vapor is mixed with the first stage liquid and then sent to the separator to remove droplets not captured by the lip 15.

The vapor mixed with the concentrate of the first stage is sent to the gas-liquid separator, and the concentrate of the second stage is discharged from the connection part 16 through the recess 14, so that the vapor at the follower end No connection to the outlet 1 is required.

Therefore, if the steam/concentrate port is common, connections to the follower are unnecessary except for supplying the second stage.

FIG. 2 shows another embodiment of the invention, in which a dividing bar 8 as well as a dividing bar 11 in said concentrate/steam outlet 1;
Instead of the dish 12, a dish 17 is provided which extends from the extension 7 of the barrier plate 6 through the head 3 to the downstream side of the recess 14 of the discharge pipe 13.

This plate 17 must be supported within the outlet 1 by means not shown. Furthermore, since the plate 17 extends considerably outside the outlet 1, it is anticipated that this will be disadvantageous in assembling the evaporator. In order to solve this problem, as shown at 17a in FIG. 3, the dish body is made short so that it ends inside the discharge port 10, and at the same time, it is fixed inside the discharge pipe 13 and extends downstream from the recess 14. It may also be slightly polymerized with the other plate body 18 (・
.

Furthermore, according to British Patent Application No. 51347/71 by the present inventor, the flow path space between each plate is divided into two or more flow paths each having separate concentrate and vapor outlets. I understand that it is okay.

By applying the present invention to either or both of these separate concentrate and vapor outlets, three
~4 evaporation stages can be defined and all concentrate/vapor outlets are provided at the head end of the plate group.

In that case, it is desirable to provide a recess 14a similar to the recess 14 in the dish body 12 or 18 as shown in FIG.
This allows liquid from the concentrate and vapor in channel 1a to be removed before it is mixed with the vapor.

A discharge pipe 16a for taking out the concentrate in the recess 14a independently of the discharge pipe 13 may be provided on one side as shown in FIG.

In FIGS. 4 and 5, reference numeral 15a indicates a glue horn portion of the recess 14a.

In both of the above embodiments, it is also possible to move the dividing plate obliquely in the discharge pipe or to arrange it so that the liquid from both evaporation stages is guided on alternate sides of the discharge pipe. It can also be configured such that liquid from a stage does not join the vapor flow from the other stage.

It goes without saying that the present invention is not limited to the illustrated embodiments, and that various changes can be made without departing from the spirit of the present invention.

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts showing a first embodiment of the present invention, FIG. 2 is a sectional view of essential parts showing a second embodiment of the invention, and FIG. 3 is a sectional view of essential parts showing a third embodiment of the invention. 4 is a sectional view of a main part showing a fourth embodiment of the present invention, and FIG. 5 is a schematic side view of the fourth embodiment. (Explanation of symbols), 1...Concentrate/steam outlet,
1a, Ib...Flow path, 2...Plate group, 6...Barrier plate, 7...Extension of barrier plate, 8, 11... ...Dividing bar 9...
Gasket, 12, 17, 17a. 18...Dish body, 13...Discharge pipe, 14
, 14a... recess, 15. i5a...
Lip part, 16...Liquid discharge connection part, 16a
...Exhaust pipe.

Claims (1)

[Claims] 1. A plate-type evaporator with a group of plates mounted in a frame between a fixed head and a movable follower, the group of plates having closed supply liquid inlet holes and concentrate/vapor discharge holes. Divided into two groups by a partially closed partially closed plate, the concentrate/steam outlet of the plate group on the fixed head side is divided into two channels, and one of these channels is connected to the plate on the fixed head side. At the same time, the partially closed plate blocks communication with the concentrate/vapor outlet from the other plate group, and the other flow path is connected to the liquid flow space between the groups. communicating with a steam outlet and extending both channels to a common outlet, and removing concentrate and steam from the other plate group before the steam from both plate groups is mixed at said outlet. A plate-type evaporator characterized by being equipped with a separation device. 2. The plate type evaporator according to claim 1, wherein the outlet is provided with a plate extending downstream from the separation device as an extension of the division downstream of the concentrate/steam outlet. 3. The plate type evaporator according to claim 2, wherein the separation device is a recess formed in the wall of the discharge pipe constituting the outlet. 4. The plate-type evaporator according to claim 3, characterized in that a lip portion is provided upright at the downstream end of the recess. 5. Claims 1 to 4, characterized in that the division of the concentrate and steam outlet is performed by a dividing bar extending in a direction transverse to the concentrate and steam outlet in each plate and having a gasket. Plate type evaporator according to any of paragraphs. 6. Claims 1, 3, and 4, characterized in that the concentrate/steam outlet is divided by a plate extending along the outlet from the partially closed plate to the end on the head side. The plate type evaporator according to any one of the above. 7. A plate-type evaporator according to claim 2, characterized in that the concentrate/steam outlet is divided by a plate extending along the outlet from the partially closed plate to the head side end. 8. The plate type evaporator according to claim 7, wherein the plate in the concentrate/steam outlet is partially polymerized with the plate in the outlet. 9. The plate-type evaporator according to claim 7, wherein both the plate bodies are part of an integral plate structure. 10. Claim 1, further comprising a further plate for removing liquid from the concentrate and vapor in one of the channels before the vapors from both plate groups are mixed at the outlet. The plate type evaporator according to any one of items 9 to 9. 11 By dividing the flow space between the plates into two or more flow areas and at the same time providing separate concentrate/vapor discharge holes in each flow area, each set of flow areas can be provided with separate concentrate/vapor discharge holes. 11. A plate-type evaporator according to any one of claims 1 to 10, characterized in that an outlet is defined and any or all of these individual outlets are divided.