JPH0672754B2 - Anti-sticking device for heat transfer tubes of heat exchangers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention is directed to the attachment of a scale or the like which is provided inside a U-shaped heat transfer tube of a heat exchanger and prevents scale, sludge and the like from adhering to the inner surface of the tube. The present invention relates to a prevention device.

[Prior Art] Generally, when a heat transfer tube type heat exchanger is used for a long period of time, deposits such as scale and sludge are formed on the inner surface of the heat transfer tube, which deteriorates the performance of the heat exchanger. Therefore, such a heat exchanger cannot be continuously operated for a long period of time, and it is necessary to temporarily stop the passage of liquid to the heat transfer tube and clean the inside of the heat transfer tube in a periodic repair or the like. If you try to clean the heat transfer tube regularly in this way, the scale and sludge attached to the inner surface of the heat transfer tube will be stuck firmly, so even if you use a forced cleaning method, it will not be completely removed. There was a problem that I could not. Therefore, various means have been devised to constantly clean the inner surface of the heat transfer tube even while the heat exchanger is in operation.

For example, in a heat exchanger having a straight tube type heat transfer tube, a long cleaning member having a coil shape is passed through the tube and both ends thereof are fixed. There is known a means for vibrating this coil by the force of the fluid flowing in the tube to prevent the scale or the like from adhering to the inner surface of the tube. Further, a brush member is provided slidably in the straight pipe type heat transfer tube, and the inner surface of the heat transfer tube is cleaned by reciprocating the brush member in the heat transfer tube using the pressure of the fluid in the tube. A cleaning means that has been proposed is also proposed.

[Problems to be Solved by the Invention] Regarding the means using the coil-shaped cleaning member, the long coil-shaped cleaning member is plastically deformed by the movement of the fluid and stretched, making it impossible to reuse the coil. In addition, the outer peripheral surface of the coil slides over the heat transfer tube over a long area, resulting in a large pressure loss and damaging the inner wall of the heat transfer tube. Regarding the means for providing the brush member in the heat transfer tube, the flow direction of the fluid needs to be switched by a three-way valve in order to reciprocate the brush member in the straight tube, but the pressure in the heat transfer tube is temporarily changed during this switching. Will decrease,
Due to the material of the brush, there is a problem that it cannot be applied to high temperature fluids. Further, according to this means, there is a problem that the equipment becomes considerably large-scaled and installation and maintenance require a great cost. All of these conventional means are applied only to a straight tube type heat transfer tube, and cannot be applied to a U-shaped tube.

[Object of the Invention] It is provided inside a U-shaped heat transfer tube to prevent scales from adhering to the inner surface of the heat transfer tube at all times even when the heat exchanger is in operation. It is an object of the present invention to provide a device for preventing adhesion of scales, etc., which does not end up and has a small pressure loss.

[Means for Solving the Problems] As shown in FIG. 1 showing the first embodiment, the device for preventing adhesion of scale or the like in the heat transfer tube of the heat exchanger according to the present invention is a A core wire 2 which is inserted into the U-shaped heat transfer tube 1 and whose both ends are fixed in the vicinity of both open ends of the heat transfer tube 1, and a core wire 2 in the heat transfer tube 1 which is attached in series with a space therebetween, A spherical cleaning ball 4 having a plurality of grooves on its outer peripheral surface that disturbs the flow of the fluid in the heat transfer tube 1 by vibrating by the motion of the fluid in the heat transfer tube 1, and the core wire 4 in the heat transfer tube 1 in series. And a centering jig 6 which is interposed and has at least a part of its outer periphery made of a coil spring having a diameter larger than that of the cleaning ball 4.

[Operation] The cleaning ball 4 is provided with the U-shaped heat transfer tube 1 by the centering jig 6.
Is held in the substantially central portion of. During operation, the fluid flowing in the heat transfer tube 1 receives fluid pressure in the groove on the outer circumference of the cleaning ball 4, whereby the cleaning ball 4 vibrates in the tube in the radial direction and the centering jig 6 is composed of a coil spring. Vibrates in the axial direction and disturbs the flow of fluid in the tube, thereby providing a uniform and reliable cleaning action over the entire inner surface of the U-shaped heat transfer tube 1.

[Embodiment] A first embodiment of the present invention will be described with reference to FIG.

In the figure, 1 is a U-shaped heat transfer tube in a multi-tube heat exchanger. A core wire 2 as a core material is inserted into the heat transfer tube 1, and both ends of the core wire 2 are open ends of the heat transfer tube 1 via springs 2 ′ for applying tension to the core wire 2. It is fixed to. Any fixing method may be used, but for example, wedge-shaped plate-like members 3a, 3 in which the end of the spring 2'is provided at the open end of the heat transfer tube 1.
If it is fixed to b, the core wire 2 comes to the center of the heat transfer tube 1 and the plate member is firmly fixed to the inner wall of the tube by the tension of the spring, which is preferable. In this embodiment, the U-shaped heat transfer tube 1 having a length of about 3 m and an inner diameter of 21.0 mm is provided with a core wire 2 made of stainless steel and having a diameter of 0.6 mm to 0.88 mm. Next, the core wire 2 is provided with a plurality of cleaning balls 4 as cleaning members at intervals of about 2 to 10 times the inner diameter of the heat transfer tube. This cleaning ball 4 is preferably one that does not damage the heat transfer tube and is excellent in heat resistance. In this embodiment, a hollow aluminum ball is used. Also, the size of the ball is
It is selected as appropriate considering the inner diameter of the heat transfer tube and the flow velocity of the fluid, but setting the outer diameter of the ball to 1/4 to 3/4 of the inner diameter of the heat transfer tube is effective for preventing scale adhesion. Preferably, in this embodiment, it is 7 to 10 mm. Further, on the surface of the cleaning ball 4, in order to increase the turbulence of the fluid, increase the vibration of the ball, and increase the effect of preventing the adhesion of scale or the like,
It is preferable to cut an oblique groove having a width of 1 mm and a depth of 0.5 mm.

Further, a coil spring-shaped centering jig 6 is attached to the U-shaped portion of the heat transfer tube. In this centering jig 6, the circular bottom portion is guided to the inner surface of the tube so that the core wire 2 attached to the axial center of the jig is positioned at the center of the heat transfer tube 1.
The cleaning ball 4 provided on the core wire 2 is always positioned at the axial center of the heat transfer tube 1.

Next, the adhesion preventing device for scales etc. having the above structure is
The operation and effect of the heat exchanger during operation will be described.

According to the apparatus of the embodiment, each cleaning ball 4 is positioned at the center of the heat transfer tube 1 by the centering jig 6 while keeping a predetermined interval. The outer peripheral groove of each cleaning ball 4 receives the force of the fluid flowing inside the tube, vibrates in the diameter direction at the center of the heat transfer tube 1, and vibrates in the axial direction by the expansion and contraction of the centering jig 6 to cause the heat transfer tube to move. Disturbance is generated in the fluid within 1. Since the turbulence of the fluid cleans the inner surface of the heat transfer tube 1 uniformly and reliably, no deposit such as scale or sludge is formed on the inner surface of the heat transfer tube 1. Or even if deposits are generated,
While the heat exchanger is in operation, this device always gives a cleaning action to the inner surface of the pipe, so that the adhered matter is removed before it solidifies, so that the inner surface of the heat transfer tube 1 is always kept clean. Further, in the U-shaped portion of the heat transfer tube 1, the centering jig 6 can generate turbulence in the fluid so that the inner surface of the U-shaped portion can be sufficiently cleaned. Further, since the present apparatus has an extremely compact structure and the differential pressure generated in the fluid when installed in the heat transfer tube 1 is as low as 0.1 to 0.5 kg / cm 2, there is no problem in practical use. Further, when it is necessary to keep the differential pressure as low as possible, the cleaning ball 4 should be considered in consideration of the type of fluid and the flow velocity.
It suffices to adjust the mounting interval and size. Further, the core wire 2 holding each part of the apparatus is not a coil shape which is easily plastically deformed as described in [Prior Art], but a cleaning member is attached to a durable stainless wire material. , There is no risk of deformation even if used continuously for a long period of time.

Next, a second embodiment of the present invention will be briefly described with reference to FIG.

The anti-adhesion device of this embodiment is also attached to the U-shaped heat transfer tube 1 similarly to the above-mentioned embodiment, and always works during the operation of the heat exchanger. The core wire 2 and its fixing method are the same as those in the above-mentioned embodiment.

In the second embodiment shown in FIG. 2, an outer diameter of 7 to 7 made of hollow aluminum is used as a cleaning member at predetermined intervals.
A plurality of 10 mm cleaning balls 4 are provided. Also,
A conical coil spring-shaped centering jig 11 is attached to the core wire 2 between the adjacent cleaning balls 4, 4. The centering jig 11 has a conical bottom portion guided to the inner surface of the tube so as to be positioned at the axial center thereof, and the cleaning ball 4 provided on the core wire 2 is always positioned at the axial center of the heat transfer tube 1. Is. According to this embodiment, each cleaning ball 4 vibrates by the force of the fluid flowing in the pipe, disturbs the flow of the fluid, and uniformly and reliably cleans the inner surface of the pipe.

In addition, in the second embodiment shown in FIG. 2, it is possible to obtain substantially the same effects as the embodiment shown in FIG.

EFFECTS OF THE INVENTION According to the present invention, in an adhesion preventing device such as a scale in which both ends of a core wire 2 which is a main body of the adhesion preventing device are fixed near both open ends of a U-shaped heat transfer tube 1 of a heat exchanger, The core wire 2
A plurality of spherical cleaning balls 4 having grooves on the outer peripheral surface thereof
Since at least a part of the outer circumference of the cleaning ball 4 is provided in series with the cleaning ball 4, the centering jig 6 is made of a coil spring having a diameter larger than that of the cleaning ball 4. Since it is held substantially at the center of the shaft center, it is possible to remove deposits on the inner surface of the wall of the U-shaped heat transfer tube 1 based on the vibration of the cleaning ball 4 caused by the fluid.

Further, when the heat exchanger is in operation, the cleaning balls 4 constantly vibrate in the pipes in the radial direction due to the fluid pressure in the grooves on the outer circumference of the cleaning balls 4 due to the motion of the fluid flowing in the heat transfer tube 1, and the coil springs. By vibrating in the axial direction by the axial expansion and contraction of the centering jig 6 made of, and disturbing the flow of the fluid in the tube, a uniform and reliable cleaning action is given to the entire inner surface of the U-shaped heat transfer tube 1.

Furthermore, compared to a conventional device consisting of only a coil spring, it is less damaged by elongation and can withstand continuous use for a long period of time, and the inner wall surface of the heat transfer tube 1 is damaged by sliding with the coil spring. And the pressure loss is small.

[Brief description of drawings]

FIG. 1 is a schematic structural diagram showing a first embodiment of the present invention, and FIG. 2 is a schematic structural diagram showing a second embodiment. 1 ... Heat transfer tube, 2 ... Core wire as core material, 4 ... Cleaning balls as cleaning member, 6,11 ... Centering jig.

Claims (1)

[Claims] 1. A core wire which is inserted into a U-shaped heat transfer tube of a heat exchanger and whose both ends are fixed in the vicinity of both open ends of the heat transfer tube, and a core wire in the heat transfer tube, which is spaced from the core wire in series. A spherical cleaning ball having a plurality of grooves on its outer peripheral surface, which are mounted and which disturb the flow of the fluid in the heat transfer tube by vibrating by the motion of the fluid in the heat transfer tube, and the core cleaning wire in the heat transfer tube. An apparatus for preventing adhesion of scale or the like in a heat transfer tube of a heat exchanger, which is provided with a centering jig that is provided and has at least a part of an outer periphery of a coil spring having a diameter larger than that of the cleaning ball.