FIELD OF THE INVENTION:
The present disclosure relates to a distribution system for distributing juice/liquid within a falling film evaporator, in particular in the sugar and food industries. More particularly, the present disclosure provides a distributor ensuring proper distribution and recirculation of juice / liquid over the heating surface to avoid any drying of heating surface and/or scaling/ choking of the tubes.

BACKGROUND OF THE INVENTION:

The falling film tubular evaporator (FFTE) are generally used for increasing concentration of liquid by evaporation process. The liquid needs to be evaporated, flow from top to bottom of vertical tube in form of film. The saturated steam acts as a heating media on other side of the tubes. To maintain good film certain amount of liquid need to be recirculated and distributed at the top portion called tube plate of falling film evaporator. Several variants of falling film tubular evaporators (FFTE) are in use in cane sugar industry. Most of these suffer from following main draw backs viz. (i) occasional tube chokes due to uneven distribution of juice, (ii) absence of headroom between top tube sheet and juice distributor necessitating its dismantling for mechanical de-scaling of tubes.

Also, at any dry portion of heating surface the liquid starts burning resulting in formation of char which further choked the tubes and particular heating surface area of such tube has no contribution in evaporation. In this way poor distribution leads to higher scaling and choking of tubes resulting in inefficient use of evaporators heating surface. The earlier designs used the series set of V or other section channels to evenly distribute the liquid in tubes. The efficiency of such distributor depends on proper leveling, liquid quality etc..Any misalignment or change in level disturbs the distribution efficiency. In addition, if liquid has impurities which settle down in channels, cause to reduce the distributor performance to great extent. Moreover, the known distributor required complete dismantling during mechanical / hydro jet cleaning. Assembly of such type distributor also need special skills& time.

US7670572 B2 relates to a distributor includes first and second liquid distribution systems for two liquid phases for an upright tube-bundle reactor. The first system is arranged directly above or on a tube sheet and is connected to at least one outer feed device and contains an annular weir. The second system is connected to at least one other outer feed device and contains one upper and one lower distribution tray which contains a plurality of openings which are arranged flush above the inlet sleeves of the first system, and has at least one device for setting a uniform liquid level above the openings. The upper distribution tray is connected to the feed device for liquid, and contains a plurality of overflow weirs from which the liquid is able to discharge into the lower distribution tray. Each of the overflow weirs is assigned to a plurality of openings of the lower distribution tray.

WO 1997007867 relates to a liquid distributor for an evaporator, particularly meant for a film evaporator treating liquid suspensions containing solids. The distributor comprises a channel array that distributes the liquid fed in at the sides of the evaporator to the top of the heat transfer surface, over the whole width thereof. The channel array is formed of at least one transversal supply channel and of a number of distribution channels departing downwards from the supply channel and leading to the heat transfer surface. Each distribution channel is provided, on its side located downstream with respect to the supply channel flow, with a step-shaped expansion bordered by a sharp point, the purpose of said expansion being to prevent liquid suction created in the channel due to the effect of siphonage.

DE3419172C1 relates to an apparatus for the uniform distribution of liquid onto the heating tubes set into tube sheets of falling film evaporators, in particular in the sugar industry, having a liquid feed and a plurality of stages of annular channels, arranged one beneath the other and subdivided into the same number of straight chambers, having an overflow on both sides, the overflow edges of the channels of the lowest channel stage being tooth-shaped and the folded outlet teeth lying above the bridges of the tube sheet. The virtually velocity-independent distribution onto the tube sheet is ensured by conducting the volume running off onto the tube sheet by drawn-down staggered guide rods independently in a parabola.

However, the above mentioned documents do not provide a failsafe distribution system. Also, these documents do not provide the solution to avoid any drying of heating surface and scaling / choking of the tubes in the falling film evaporator.
OBJECT OF THE INVENTION:
An object of the present disclosure is to provide a distribution system within a falling film evaporator to handle juice / liquid with impurities that can be easily be dismantled for maintenance.

Another object of the present disclosure is to ensure uniform wetting of each and every tube of the falling film evaporator to avoid drying of the heating surface at any time.

SUMMARY OF THE INVENTION:

An aspect of the present disclosure is to provide a distribution system for distributing juice / liquid within a falling film evaporator comprising:
an inlet for supplying juice / liquid to the system;
a weirbox, having an opening for receiving the juice / liquid from said inlet and one or more openings toward bottom of the weirbox for supplying the juice to a first stage distributor portion;
the first stage distributor portion having a plurality of channels, the channels arranged in more than one substantially horizontal planes in cascaded relationship with the channels in an adjacent plane; and
a second stage distributor portion having a plurality of substantially vertically oriented tubes, the second stage distributor configured to receive the juice from said first stage distributor;
characterized in that
the plurality of channels have a plurality of notches on top edges of sides to urge the juice overflowing from the notches to fall under gravity into channels in lower adjacent plane to transform the juice into form of a free falling shower, and that
the second stage distributor portion has a plurality of segmented trays, each segmented tray having an umbrella like element arranged vertically over each of the plurality of the substantially vertically oriented tubes for preventing direct entry of free falling juice shower in to the tube and transforming said juice into a film uniformly wetting said tubes.

An embodiment of the present disclosure provides that the distribution system has two stages.

Another embodiment of the present disclosure provides the channels have V-shaped, U-shaped or half ellipse shaped.

Another embodiment of the present disclosure provides the channels have a plurality of notches on top edges of the sides of channels.

Another embodiment of the present disclosure provides the first stage distributor portion is arranged vertically above the second stage distributor portion at a distance from two to three meters.

Another embodiment of the present disclosure provides each segmented tray is bolted to the top of a tube sheet for easy dismantling.

Still another embodiment of the present disclosure provides the umbrella like element is welded to the segmented tray.

Still another embodiment of the present disclosure provides the tripod umbrella like element is a tripod umbrella having three legs joined with a dish like element.

Yet another embodiment of the present disclosure provides the plurality of tubes are welded to a tube sheet.

Yet another embodiment of the present disclosure provides the weirbox has a weir for regulating flow of the juice.

These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the subject matter, nor is it intended to be used to limit the scope of the subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS:
The above and other objects and features of the present invention will become apparent from the following description of the invention, when taken in conjugation with the accompanying drawings, which respectively show:

Figure 1(a)shows distribution system of the falling film evaporator as per embodiment of the present disclosure;
Figure 1(b) shows segmented tray used in the distribution system;
Figure 1(c) shows distribution of juice / liquid from 2nd stage distributor;
Figure 1(d)& 1(e): shows segment of tray along with tripod umbrella;
Figure 1(f): schematic view of system of the present disclosure;

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:

The evaporation achieved from a falling film evaporator is majorly dependents on the proper wetting of heating surface i.e. the heating surface shall not be dried any time. This section of the disclosure describes an exemplary embodiment of the present invention that provides even distribution of the juice / liquid, which is to be evaporated at the inner surface of tubes particularly in long tube film type tubular evaporator.

The distribution system of the present disclosure comprises a first stage distributor portion having an inlet weir box and multi-stage cascaded system which forms a uniform shower of juice across the entire cross section. It may be installed at a distance ranging from two to three meters above the top tube sheet of second stage distributor portion to facilitate easy access to various tubes for inspection or mechanical de-scaling without its dismantling. A segmented tray plate bolted to top tube sheet and having individual tripod type umbrella located over each tube, ensures equal wetting of each and every tube, making the system failsafe. The present distribution system with tripod umbrella is a two stage distribution system, which is arranged in cascade manner. The system of the present disclosure provides the solution to shortcomings of the prior arts.

First stage portion of the distributor:
The first stage has weirbox with plurality of V channels, for this embodiment three sets of V-channels have been taken for the distribution system.
Referring to Figure1(a), the juice / liquid from the inlet is sealed in a weirbox and allow to over flow to first level V-channels. The juice / liquid then overflows from first level channels to second level and then 3rd level V-channels; finally is distributed evenly over the final stage distributor in form of shower. The number of stages can be decided based on the dimensions of the evaporator over which the liquid needs to be distributed. Two holes may be provided in bottom of the each V channels which will not allow any settling of impurities in V channels. The final stage V-channels may have a plurality of notchesat the top edges which facilitate overflow inform of shower.

Second stage portion of the distributor:
Referring to figure 1(b),showing the segmented tray plate, which comprises individual tripod umbrella like element located over each tube and welded to the tray. This tray is segmented and bolted to a tube sheet for ease of dismantling.

Referring to figure 1(c), the juice / liquid from first stage distributor spreadsover the segmented tray and the remaining portion of tube sheet in form of shower. As all the tubes are covered by a tripod umbrella like element, no liquid can directly go to the tubes. The juice/ liquid then overflows, making a film at inside surface of the evaporator tubes. The second stage portion of the distributor may be installed at a distance from two to three meters above the top tube sheet to facilitate easy access to various tubes for inspection or mechanical de-scaling without its dismantling as shown in the cut section in Figure1(d). Each segment of the tray along with the tripod umbrella like elements can be easily removed and placed along the wall to allow easy access to the tubes.

The juice / liquid distribution system of the present disclosure is simple, yet rugged and reliable. It also ensures uniform wetting of each and every tube of the falling film tubular evaporator (FFTE)and enables formation of a film on the internal surface of the evaporator tubes. The cascade distributor once assembled inside the FFTE vessel need not be disturbed or dismantled even during the off-crop season.

ADVANTAGES:

• Simple, yet rugged and reliable.
• Failsafe distribution system as no liquid can directly enter the tubes even in case of the first stage V-Channels get choked& give improper distribution;
• Provide ease of tube cleaning without dismantling the top end;
• easy to dismantle as the segmented tray portions are lighter in weight & can be handled by operator without any special lifting accessories;
• the cascade distributor once assembled inside the FFTE vessel need not be disturbed or dismantled;
Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the scope of the disclosure should not be limited to the description of the preferred embodiment contained therein.

We claim:

1. Adistribution system for distributing juice / liquid within a falling film evaporator comprising:
an inlet for supplyingjuice / liquid to the system;
a weirbox, having an opening for receiving the juice / liquid from said inlet and one or more openings toward bottom of the weirbox for supplying the juice to a first stage distributor portion;
the first stage distributor portion having a plurality of channels, the channels arranged in more than one substantially horizontal planes in cascaded relationship with the channels in an adjacent plane; and
a second stage distributor portion having a plurality of substantially vertically oriented tubes, the second stage distributor configured to receivethe juice from said first stage distributor;
characterized in that
the plurality of channels have a plurality of notches on top edges of sides to urge the juice overflowing from the notches to fall under gravity into channels in lower adjacent plane to transform the juice into form of a free falling shower, and that
the second stage distributor portion has a plurality of segmented trays,each segmented tray having an umbrella like element arrangedvertically over each of the plurality of the substantially vertically oriented tubes for preventing direct entry of free falling juice shower in to the tube and transforming said juice into a film uniformly wetting said tubes.

2. The distribution system as claimed in claim 1, wherein the distribution system has two stages.

3. The distribution system as claimed in claim 1, wherein the channels have V-shaped, U-shaped or half ellipse shaped.

4. The distribution system as claimed in claim 1, wherein the channels have a plurality of notches on top edges of the sides of channels.

5. The distribution system as claimed in claim 1, wherein the first stage distributor portion is arranged vertically above the second stage distributor portion at a distance fromtwo to three meters.

6. The distribution system as claimed in claim 1, wherein each segmented tray is bolted to the top of atube sheet for easy dismantling.

7. The distribution system as claimed in claim 1, wherein the umbrella like element is welded to the segmented tray.

8. The distribution system as claimed in claim 1 or 7, wherein the tripod umbrella like element is a tripod umbrella having three legs joined with a dish like element.

9. The distribution system as claimed in claim 1, wherein the plurality of tubes are welded to a tube sheet.

10. The distribution system as claimed in claim 1, wherein the weirbox has a weir for regulating flow of the juice.