CN1202892C - Automatic cleaning type falling-film evaperator - Google Patents

Abstract

An automatic cleaning type falling film evaporator comprises an evaporator and a cleaning device. The evaporator includes an evaporation chamber and a heating chamber composed of an upper tube sheet, a lower tube sheet, and a falling film heat exchange evaporation plate. The cleaning head consisting of a hollow rubber wiper and a rubber wiper holder is embedded in the evaporation chamber. When the cavity of the hollow rubber wiper is filled with a certain pressure of compressed air, the volume increases, and the outer edge of the rubber wiper is in close contact with the inner wall of the evaporation chamber. . The cleaning head is connected with the motor arranged above the outside of the vertical basket-shaped container through the cleaning head traction and power transmission mechanism, so as to realize the up and down movement and clean the falling film heat exchange evaporation plate. The cleaning device operates independently and does not affect the normal operation of the evaporator evaporation process. The self-cleaning falling film evaporator of the present invention can clean all the heat exchange surfaces of the falling film evaporator while the evaporator is working, so that the thermal resistance on the heat exchange surface of the falling film evaporator can be kept at a very low level for a long time, and the evaporator The thermal efficiency is significantly improved, and the energy consumption is greatly reduced.

Description

Automatic cleaning falling film evaporator

technical field

The invention relates to an evaporator, in particular to a falling film heat exchange evaporator which can automatically clean the heat exchange surface while working.

Background technique

Falling film heat exchange evaporators are widely used in petrochemical industry, food industry, pharmaceutical industry, paper industry, environmental protection and seawater desalination and other industrial fields. After long-term use, dirt will be generated on the heat exchange surface of the evaporator, which will reduce the heat transfer coefficient, increase the required heat transfer area of the equipment, increase equipment investment, increase frictional resistance, and increase steam consumption. The driving force increases.

Existing method for removing dirt mainly adopts artificial, mechanical method or chemical method to clean after parking and dismantling. resulting in reduced production losses. The online non-disassembly cleaning device can solve this problem very well. Such as ultrasonic vibration method, gas jet method, sponge rubber ball system and wire brush system, etc. These methods are generally only applicable to certain heat exchangers. As for evaporators, especially rising and falling film evaporators, such as the plate falling film evaporator disclosed by the inventor in the international patent WO95-052257, the above-mentioned online cleaning method without disassembly cannot be used. Manual, mechanical or chemical methods for cleaning, resulting in greater economic losses.

Contents of the invention

The technical problem to be solved in the present invention is to disclose a self-cleaning falling film evaporator, so as to overcome the defects in the prior art that online cleaning cannot be performed, resulting in relatively large economic losses.

Technical scheme of the present invention:

The automatic cleaning type falling film evaporator of the present invention comprises an evaporator and a cleaning device;

The evaporator is a vertical basket-shaped container, including a feed liquid distributor on the upper part of the container, and an evaporation chamber composed of an upper tube sheet, a lower tube sheet, a falling film heat exchange evaporation plate and a heating chamber arranged under the feed liquid distributor. room;

The cleaning device includes a cleaning head, a cleaning head traction and a power transmission mechanism.

The mentioned cleaning head includes a hollow rubber wiper and a rubber wiper fixing frame. The rubber wiper fixed frame is embedded in the evaporation chamber, and the hollow rubber wiper is fixed under the rubber wiper fixed frame. The hollow rubber wiper is connected with the compressed air source through the pipeline. There is a gap between the outer edge of the hollow rubber wiper and the inner wall of the evaporation chamber. When the cavity of the hollow rubber wiper is filled with compressed air of a certain pressure, the hollow rubber wiper expands under pressure, and the volume increases, so that the outer edge of the rubber wiper is in contact with the inner wall of the evaporation chamber. are in close contact with each other.

The cleaning head is connected with the motor arranged above the outside of the vertical basket-shaped container through the cleaning head traction and power transmission mechanism.

When the self-cleaning falling film evaporator of the present invention works, the evaporator is the same as the conventional evaporator. The cleaning device operates independently and does not affect the normal operation of the evaporator evaporation process. The cleaning device is controlled by a timing device, and the cleaning device operates once at regular intervals (intermittently adjustable). When starting to clean, open the compressed air valve, pressurize the hollow rubber wipes, make each rubber wipe fully contact with the inner wall of the evaporation chamber with a certain pressure, the motor rotates, and the cleaning head is driven downward by the traction of the cleaning head and the power transmission mechanism. Movement, to clean all the heat exchange surfaces, the movement speed is preferably 0.3-2m/s, so that the movement speed of the cleaning head is equivalent to the flow rate of the falling film of the material liquid, and the liquid film will not be damaged during cleaning. When the cleaning head moves downward, the evaporation chamber is divided into upper and lower parts. The pressure difference between these two parts is balanced by 4 pressure balance tubes. The cleaning head runs to the bottom of the evaporator to complete a cleaning of the heat exchange surface; open the vent valve , so that the hollow rubber rubbing compression is small, and the motor is reversed, the cleaning head goes up, returns to the upper head to stop, and completes a cleaning operation process. Repeated cycle, the evaporator can be cleaned online, and the pressure of compressed air can be adjusted to change the contact pressure between the rubber wiper and the surface of the evaporation chamber.

In summary, the self-cleaning falling film evaporator of the present invention can effectively clean all the heat exchange surfaces of the evaporator while it is working, and can keep the thermal resistance on the heat exchange surface of the falling film evaporator at a very high level for a long time. At low levels, cleaning has no adverse effect on the normal conduct of evaporation operations. According to different materials and working conditions, the appropriate cleaning time interval and contact pressure can greatly reduce the economic loss caused by the dirt in the evaporator and reduce the labor intensity of cleaning. Since the thermal resistance on the heat exchange surface of the self-cleaning falling film evaporator can be controlled at an arbitrarily low level for a long time, the heat transfer coefficient can be maintained at a very high level from the beginning to the end, so that the thermal efficiency of the evaporator is significantly improved and the energy consumption is greatly reduced. .

Description of drawings

Fig. 1 is a schematic structural view of the self-cleaning falling film evaporator of the present invention, which is the A-A step sectional view shown in Fig. 2 .

Fig. 2 is an E-E sectional view shown in Fig. 1 .

Fig. 3 is a cross-sectional view of F---F shown in Fig. 1 .

Figure 4 is a diagram showing the cooperation between the cleaning head and the evaporation chamber.

Fig. 5 is a B-B sectional view shown in Fig. 4 .

Fig. 6 is a sectional view of C---C shown in Fig. 4 .

Detailed ways

Referring to Fig. 1 and Fig. 3, the self-cleaning falling film evaporator of the present invention includes an evaporator and a cleaning device.

It can be seen from the figure that the evaporator is a vertical basket-shaped container, the upper part of the container is provided with a feed liquid distributor 15, the lower part of the container is provided with an upper tube sheet 11, the lower part of the container is provided with a lower tube sheet 4, the upper tube sheet 11 and The lower tube plate 4 is symmetrically opened with a plurality of longitudinal channel holes and one transverse channel hole, the longitudinal channel holes and the transverse channel holes form a “king” character, and the channel holes of the upper tube plate 11 and the channel holes of the lower tube plate 4 are connected There is a falling film heat exchange evaporation plate 6, the cavity between the upper tube plate 11 and the channel hole of the lower tube plate 4 is the evaporation chamber 5, the airtight space between the two evaporation chambers is the heating chamber 7, the evaporation on both sides of the evaporator A pair of semicircular guide grooves 21 are arranged symmetrically in the chamber 5, and air pressure balance pipes 10 are arranged in the heating chamber 7 on both sides of the evaporator, and chain holes 3 are arranged on the lower bottom wall of the container below the balance pipes 10.

As can be seen from Figures 1 and 2, said cleaning device includes a cleaning head 9, a cleaning head traction and a power transmission mechanism.

Referring to Fig. 4, Fig. 5 and Fig. 6, the cleaning head 9 mentioned above includes a hollow rubber wiper 32 and a rubber wiper fixing frame 34. The rubber wiper fixing frame 34 is a "king"-shaped frame embedded in the evaporation chamber 5. Side symmetry is provided with guide slider 30 that cooperates with guide groove 21, to guarantee the relative position accuracy between rubber wiper fixed mount 34 and evaporation chamber 5, facilitate its up and down movement simultaneously, the outer edge of rubber wiper fixed mount 34 and evaporation chamber The gap between the inner walls of 5 is 1 ~ 3mm; the rubber wiper fixed frame 34 is provided with a compressed air chamber 35 with a compressed air inlet 36, and the rubber wiper fixed frame 34 is provided with a cleaning head reinforcing rib 31 to increase the rubber wiper fixed frame. 34 strength and rigidity; the hollow rubber wiper 32 is firmly attached to the bottom of the rubber wiper holder 34, and the hollow rubber wiper 32 communicates with the compressed air chamber 35 through the pipeline 33. When the hollow rubber wiper 32 is in the decompression state, the hollow rubber wiper The gap between the outer edge of the wiper 32 and the inner wall of the evaporation chamber 5 is 1 to 3mm. When the cavity of the hollow rubber wiper 32 is filled with compressed air and expands under pressure, the volume increases, and the entire line between the outer edge and the inner wall of the evaporation chamber 5 close contact with each other;

Referring to Fig. 1 and Fig. 2, said cleaning head motion traction and power transmission mechanism include:

The motor 22 that is arranged on the outside of the vertical basket-shaped container;

The left driving shaft 24 that is connected with the motor 22 and stretches into the vertical basket-shaped container is provided with a dynamic sealing mechanism between the left driving shaft 24 and the container wall;

Carry out power transmission through the chain drive 23 and the left driving shaft 24, be arranged on the intermediate shaft 28 on the wall of the basket-shaped container, its gear ratio is preferably 1;

A hollow right driving shaft 26 whose one end transmits power through a gear 29 and an intermediate shaft 28, extends into a vertical basket-shaped container, and the other end communicates with a compressed air inlet 25 arranged on the wall of the container, has the best transmission ratio is 1, when the motor rotates, the left driving shaft 24 is equal to the right driving shaft 26 rotating speeds, and the direction of rotation is opposite, and a dynamic sealing mechanism is arranged between the right driving shaft 26 and the container wall;

Drive sprockets 16 symmetrically arranged on the left and right driving shafts 24, 26;

Be arranged on the driven shaft 1 in the driven sprocket box 38 at the bottom of the vertical basket-shaped container, and the bottom of the driven sprocket box 38 is preferably provided with a drain valve to get rid of the liquid in the driven sprocket box 38;

Correspondingly, the driven sprocket 2 disposed below the driving sprocket 16 on the driven shaft 1, the driving sprocket 16 and the driven sprocket 2 are equal in size;

One end is fixedly connected to the chain 8 on the upper side of the cleaning head 9. The chain 8 goes vertically upwards in the evaporation chamber 5, passes through the balance tube 10 vertically downwards after bypassing the driving sprocket 16, passes through the chain hole 3 at the bottom of the basket-shaped container, and then Bypass the driven sprocket 2 in the driven sprocket box 38, vertically upward in the evaporation chamber 5, and be fixed below the cleaning head 9; as can be seen from Figure 1, the chain sleeve 37 is welded on the chain hole 3, and its function To prevent the liquid from flowing out from the chain hole 3, the chain 8 passes through the chain sleeve 37;

An air pipe wheel 27 fixed on the right driving shaft 26;

Wrapped on the air pipe wheel 27, one end communicates with the compressed air chamber 35 on the rubber wiper holder 34, and the other end communicates with the air pipe 19 at the inner end of the right drive shaft 26;

As can be seen from FIG. 1 , a scraper 14 cooperating with the chain 8 is provided in the basket-shaped container to keep the chain 8 clean.

Claims (11)

1. an automatic cleaning type falling-film evaperator comprises evaporimeter, and this evaporimeter is a vertical basket container, comprises by upper perforated plate (11), lower perforated plate (4), and vaporization chamber (5) and heating clamber (7) that evaporation plate (6) constitutes is characterized in that:

(1) vaporization chamber of evaporimeter both sides (5) is symmetrical arranged a pair of semicircle gathering sill (21), is provided with barometric pipe (10) in the heating clamber of evaporimeter both sides (7);

(2) this falling film evaporator also comprises cleaning device, this cleaning device comprises cleaning head (9), cleaning head traction and power drive mechanism, the cleaning head of being addressed (9) comprises hollow rubber eraser (32), rubber is wiped fixed mount (34), it is the framework of an embedding vaporization chamber (5) that rubber is wiped fixed mount (34), its bilateral symmetry is provided with the guide runner (30) that matches with gathering sill (21), rubber is wiped fixed mount (34) and is provided with have the compressed air inlet delivery air chamber (35) of (36), hollow rubber eraser (32) is fixed on rubber and wipes fixed mount (34) below, and hollow rubber eraser (32) is connected with delivery air chamber (35) by pipeline (33);

Cleaning head (9) is connected with the motor (22) that is arranged on top, vertical basket container outside with power drive mechanism by the cleaning head traction.

2. automatic cleaning type falling-film evaperator as claimed in claim 1 is characterized in that, said cleaning head traction and power drive mechanism comprise:

What be connected with motor (22) stretches into left driving shaft (24) in the vertical basket container;

By chain and sprocket driving device (23) and left driving shaft (24) carry out transmission of power, be arranged on the jackshaft (28) on the basket container wall;

One one end by gear (29) and jackshaft (28) carry out transmission of power, stretch in the vertical basket container, hollow right side driving shaft (26) that the other end is connected with compressed air inlet (25) on being arranged on wall;

Be symmetricly set on the drive sprocket (16) on left and right driving shaft (24), (26);

Be arranged on the driven shaft (1) in the vertical basket container bottom driven sprocket box (38);

Be configured in the driven sprocket (2) on drive sprocket (16) below, the driven shaft (1) accordingly;

One end is connected in the chain (8) of cleaning head (9) upside, chain (8) in vaporization chamber (5) vertically upward, walk around drive sprocket (16) back vertically downward by balance pipe (10), pass out chain hole (3) in basket container bottom, balance pipe (10) below, walk around the driven sprocket (2) in the driven sprocket box (38) again, in vaporization chamber (5), vertically upward, be fixed on the below of cleaning head (9);

An appendix wheel disc (27) that is fixed on the right driving shaft (26);

Be wrapped in that appendix wheel disc (27) is gone up, an end is connected the appendix (19) that the other end is connected with right driving shaft (26) the inner with delivery air chamber (35) on the rubber wiping fixed mount (34).

3. automatic cleaning type falling-film evaperator as claimed in claim 2 is characterized in that, is provided with in the basket container in order to keep the material scraper (14) that matches with chain (8) of chain (8) cleaning.

4. automatic cleaning type falling-film evaperator as claimed in claim 2 is characterized in that, is welded with chain pipe box (37) on chain hole (3), and chain (8) passes chain pipe box (37).

5. automatic cleaning type falling-film evaperator as claimed in claim 2 is characterized in that, left driving shaft (24) is 1 with jackshaft (28) gear ratio.

6. automatic cleaning type falling-film evaperator as claimed in claim 2 is characterized in that, jackshaft (28) is 1 with right driving shaft (26) gear ratio of hollow.

7. automatic cleaning type falling-film evaperator as claimed in claim 2 is characterized in that, the equal and opposite in direction of drive sprocket (16) and driven sprocket (2).

8. automatic cleaning type falling-film evaperator as claimed in claim 1 is characterized in that, the gap between the outer rim of rubber wiping fixed mount (34) and the inwall of vaporization chamber (5) is 1～3mm.

9. automatic cleaning type falling-film evaperator as claimed in claim 1 is characterized in that, rubber is wiped fixed mount (34) and is provided with cleaning head reinforcement (31).

10. automatic cleaning type falling-film evaperator as claimed in claim 2 is characterized in that, is provided with sealing mechanism between right driving shaft (26) and left driving shaft (24) and the chamber wall.

11. automatic cleaning type falling-film evaperator as claimed in claim 2 is characterized in that, driven sprocket box (38) bottom is provided with tapping valve.

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