JP2001241640A - Nozzle lance for water jet cleaning and method for cleaning heating tube using the nozzle lance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively remove attachment on the surfaces of fins in a heating tube having fins, as well as to remove deposit between the fins and attachment at the bases of the fins. SOLUTION: A nozzle lance for water jet cleaning comprises a tube-like lance 14 which allows high pressure water 6 to flow therein and nozzle tips 15 for injecting water jet, which are provided at the lance, and performs cleaning by blowing water jet 17 to a heating tube bank. The lance 14 consists of a narrow and long lance which can be inserted into the gaps in the heating tube bank. A plurality of nozzle chips 15 are mounted on the side wall of a lance. Two nozzle chips are provided at positions, each of which are distanced from the other by 180 degrees with respect to the circumferential direction, and the water jets 17 are injected from the nozzle tips, respectively, in the opposite horizontal directions. The nozzle tips are disposed being deviated from each other with respect to the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure washing technique using a water jet, and more particularly to a structure of a lance with a nozzle inserted into a narrow portion such as a gap in a tube group of a heat exchanger.

[0002]

2. Description of the Related Art A boiler or the like recovers heat from exhaust gas,
There is equipment to heat the boiler feedwater. For example, in a natural gas-fired exhaust gas reburning (repowering) plant, exhaust gas from a gas turbine is passed through a gas feedwater heater, and the boiler feedwater is heated by heat exchange. Such a gas feed water heater is a heat exchanger in which finned heat transfer tubes (fin tubes) are arranged.

[0003] Exhaust gas from a gas turbine using natural gas as a fuel contains a large amount of water vapor, and a small amount of sulfur contained in the natural gas also contributes to the fin tubes to cause rust to grow. In particular, at the lowermost part in the flow direction of the exhaust gas, the temperature of the exhaust gas is lowered and moisture is condensed, so that rust is severely generated. Excessive rust deposits result in poor heat transfer, reduce plant efficiency, and impair the economics of plant operation.

Although there are several methods for removing the adhered rust, there has been a method for cleaning with a high-speed water jet, but in reality, no satisfactory results have been obtained.

FIG. 11 shows a method in which ultrahigh-pressure water exceeding 1000 kgf / cm ² is blown from the outside of the heat exchanger toward the fin tube in front. The water jet only cleans the fin tube on the front side, does not reach the inside of the fin tube row, and only a part of the heat exchange section recovers the heat transfer performance. In addition, since ultrahigh-pressure water is used, the fins may be broken.

FIG. 12 shows the shape of a conventional nozzle for blowing a water jet. Although the high-pressure water 6 is guided through the high-pressure water supply channel 9 and blows out from the ejection holes 11,
Due to the turbulence generated in the radially contracted portion 10, the water jet 7 spreads while splitting into water droplets and droplets, and the power of the jet does not continue to the downstream.

FIG. 13 shows a method of blowing a fan-shaped (fan) jet through a slit jet hole 12.
The situation is the same for this nozzle as in the example of FIG.
There is a problem that the power of the jet does not last downstream.

[0008]

The prior art has the following problems to be solved. That is, although the deposits between the fins and the deposits at the roots of the fins can be removed to some extent, the deposits on the fin surface that are deeply involved in the heat transfer performance cannot be removed efficiently. In addition, since the water jet is blown from the outside of the heat exchanger for washing, the heat transfer tube located at a deep position cannot be washed with water, and the heat transfer performance of the heat exchanger cannot be sufficiently restored.

Further, since an ultra-high pressure jet is used, power consumption is high and washing efficiency is low. Also, the use of large amounts of jet water requires a great deal of labor and cost to treat wastewater. In addition, the construction period is long because the washing efficiency is low. In addition, because the nozzle wears quickly and has low durability,
It is difficult to maintain the washing efficiency.

An object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide a nozzle lance for high-pressure washing for a narrow part having excellent performance.

[0011]

In order to solve the above-mentioned problems, the present invention mainly employs the following configuration.

A water jet cleaning nozzle, comprising: a tubular lance through which high-pressure water flows, and a water jet injection nozzle tip provided in the lance, for cleaning by spraying the water jet onto a heat transfer tube group. In the lance, the lance comprises a thin and long lance which can be inserted into a gap between the heat transfer tube groups, and a plurality of the nozzle tips are mounted on a side wall of the lance.

[0013] In the water jet cleaning nozzle lance, the injection hole may be oriented such that the water jet hits the surface of the fin provided on the heat transfer tube at an angle of 20 ° or more and 70 ° or less. A nozzle lance for water jet cleaning in which a nozzle tip is installed with respect to the lance.

In the water jet cleaning nozzle lance, the nozzle tip is installed with respect to the lance so that the injection tip is oriented such that a water jet penetrates between the fins of the heat transfer tube. Lance for jet cleaning.

In the water jet cleaning nozzle lance, a plurality of lances are connected by a fixing member so that the lances are formed in parallel to form a set of lances, and a root side of the set of lances is mounted on a manifold. A water jet cleaning nozzle lance configured to supply high-pressure water to the manifold.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A water jet cleaning nozzle lance according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically illustrates a state of high-pressure cleaning by a water jet by applying the nozzle lance for water jet cleaning of the present embodiment to a heat transfer tube group.

The heat transfer tube group to be cleaned has heat transfer tubes (fin tubes) arranged in a staggered arrangement, and a thin lance 14 having an outer diameter of 6 mm is obliquely inserted into a gap between the tube groups. The high-pressure water 6 is supplied to a flow path inside the lance 14. A nozzle tip 15 is embedded near the tip of the thin tube-shaped lance 14 with its position shifted in the axial direction of the lance 14, from which a water jet 17 blows out at a high speed, and the base tube 2 of the heat transfer tube (fin tube) 1 and the like. It collides with the fin 3. After the lance 14 is inserted into the heat transfer tube group, it is moved forward and backward or upward and downward, and after cleaning is completed, pulled out and inserted into another position in the heat transfer tube group to resume cleaning. I do.

The reaction force applied to the lance 14 by the jet of the water jet 17 is a heat transfer tube (fin tube).
Supported by one. The water jet 17 ejected from the nozzle tip 15 collides with the heat transfer tube (fin tube) 1 at a high speed, destroys and crushes corrosion products (rust) attached to the fins 3 and the mother tube 2, and flows fragments. Put out (rust becomes powder and mixes with water to form "sludge")
To remove.

FIG. 2 shows an axial section of one lance. Two nozzle tips 15 are mounted so as to be embedded in the side of the lance 14. Nozzle tip 15
And the radius of curvature R is
It is set to about 4 to 8 times the radius (Dj / 2) of the ejection hole. The roundness of the nozzle tip inlet is out of this range, for example, (Dj /
2) Under the condition of × 4 or less, there is a problem that the water flow is apt to be separated at the nozzle entrance.

On the other hand, for dimensions of (Dj / 2) × 8 or more,
If the size is larger than this, the effect is small, and the nozzle tip becomes large only from a geometrical relationship, and there is no merit of being embedded in a thin tube type lance. Therefore, the radius of curvature of the roundness at the inlet of the nozzle tip is 4 of Dj / 2.
It is preferable to select from a range of up to 8 times. In the present embodiment, the radius of curvature of the nozzle inlet is R = 2.0 mm for the ejection hole Dj = 0.8 mmφ. The two nozzle tips secure the strength of the lance 14 (since the perforations in the circumferential direction at the same position reduce the strength of the cylinder)
Displace in the axial direction.

In order to enhance the cleaning ability, one cleaning operator performs the work using an apparatus in which a plurality of lances are integrated instead of a single lance. FIG. 3 shows an example in which two lances 14 are used, in which two lances 14 are assembled in parallel to form one set. From this dual lance, a total of four water jets 17 will blow out. The two lances 14 are held by a support 18. These lances are fixed to the manifold 19 at the root. A high-pressure hose 20 is connected to the manifold 19, through which high-pressure water is supplied to the nozzle lance.

FIG. 4 shows a state in which the lance 14 is inserted into the heat transfer tube group and the water jet 17 is sprayed on the heat transfer tubes (fin tubes) 1 from an angle different from that in FIG. From the nozzle tips 15 provided on both sides of the lance 14, two water jets 17 blow out from diametrically opposite stones differing by 180 ° in diametrically opposite directions and collide with the side surfaces of the fins 3. Since the lance 14 is freely moved by a flushing operator (operator), the water jet 17 collides not only with the side surface of the fin 3 but also with the tip and the root of the fin 3 or the surface of the mother tube 2,
Remove the rust that has adhered.

The gap between the heat transfer tubes (fin tubes) 1 is not constant depending on the installation accuracy of the heat exchanger. When the gap is large, there is no problem regarding the insertion of the lance 14, but as shown in FIG. 5A, it is difficult to insert the lance 14 when the gap is small. Then, (2) of FIG.
As described above, a guide bar 16 made of a plate material having a uniform thickness is inserted in advance into a gap between the heat transfer tubes (fin tubes) 1 to create a gap through which the lance 14 can pass smoothly. The distal end of the guide bar 16 has a sharpened shape as shown in FIG. 5 (3) to facilitate insertion.

FIG. 7 schematically illustrates the behavior of a water jet blown from a nozzle according to the present invention. The inlet portion 15a of the nozzle tip 15 mounted so as to be embedded in the side surface of the lance 14 has a large radius of curvature, so that water flowing into the nozzle tip 15 does not peel off along the inner surface of the nozzle tip 15. Flow smoothly,
The water jet 17 blows out into the outside air. Immediately after the water jet 17 is jetted from the nozzle, the core portion 17a expands and splits into a water mass slightly downstream (1).
7b) Further downstream, water droplets are formed (17c).

When the water jet 17 hits an object, the strongest impact force is generated in a region where the core portion 17a splits (17b) into a water mass. Split into water bodies (1
7b) is intermittent, vibrating like a rock drill bit and repeatedly impacting the object. In this embodiment,
Thus, the region where the power of the collision of the water jet is the strongest (this is referred to as an optimum stand-off distance) corresponds to the surface of the mother pipe 2. This makes it possible to efficiently clean not only the surface of the mother tube, but also the side surfaces and the base of the fin.

In the present embodiment, the optimum standoff distance Xs is set to be 15 mm. This distance X
s is determined by the shape (dimensions) of the nozzle and the injection pressure. The reason why the optimum stand-off distance is set to Xs = 15 mm is that the height of the fin of the fin tube is 15 mm, and the most powerful force is when the jet collides with the root of the fin (tail) and the surface layer of the mother tube. Is intended to increase.

FIG. 8 shows a prior art (FIG. 2) regarding an effective water-washing fin tube array from the front side of a heat exchanger composed of a group of fin tubes for water jet cleaning.
2) is a comparison between the embodiment of the present invention (FIGS. 1 to 5). Here, “effective water washing” means that rust was removed by the water jet, and that the effect of washing occurred. The prior art only sprays a water jet from the outside of the heat exchanger to the foremost fin tube, so that cleaning is effective only in the third row from the near side. To this extent, only a very small portion of the heat exchanger has been cleaned, and the recovery of the heat transfer performance is also slight.

On the other hand, in the embodiment of the present invention to which the method of internally inserting the long lance was used, it was possible to clean the fin tubes up to the 14th row corresponding to the length of the lance. Since the heat exchanger has 14 rows of fin tubes in the depth direction, the fin tubes are penetrated to the entire area of the heat exchanger, and the internal cleaning of the fin tube group has been achieved.

FIG. 9 compares the removal rate of rust attached to the fin tube between the prior art and the embodiment of the present invention. The rust removal rate on the vertical axis was made dimensionless by dividing the rust removal amount r by the rust removal amount r ^* in the prior art. Therefore, in the prior art, r / r ^* = 1.
The amount of rust removed can be determined by measuring the weight of sludge contained in the wastewater. In an embodiment of the present invention, r
/ R * ⁼ 4.7 next, it can be seen that was able to remove both of the rust of nearly 5 times of the prior art. As a result, the effect of cleaning to a deep position in the tube bank was demonstrated.

Further, the effect of the high-pressure washing according to the present invention was confirmed by the recovery of the heat transfer performance in the heat exchanger. FIG.
Is a comparison between the water washing method of the present embodiment and the prior art for recovery of heat transfer performance. The vertical axis represents the temperature ΔT representing the recovery of the heat transfer performance, and is made dimensionless by dividing by the temperature ΔT ^* recovered in the related art. That is, in the prior art, ΔT / ΔT ^* = 1. According to the present embodiment, ΔT / ΔT ^* increased to nearly three times, and a clear effect of heat transfer performance recovery was recognized. From the above results, the effect of implementing the present embodiment is specifically demonstrated.

Next, another embodiment of the present invention will be described.
This is an embodiment for expanding a heat transfer tube (fin tube) without using a guide bar 15 as shown in (2) of FIG. 5, and this is shown in FIG. A tip guide plate 17 (having a tapered shape for pushing and spreading the fin tube), which serves as a support for connecting the two lances 14 and has a tip protruding forward of the top of the lance 14, is provided between the two lances 14. It is provided at the tip of the lance 14.
In this way, simply by pushing the lance 14 into the gap between the heat transfer tubes (fin tubes), the interval between the heat transfer tubes (fin tubes) is widened, and the lance 14 can be inserted into the heat exchanger. In this embodiment,
The head of the distal end guide plate has a rounded shape so that the lance 14 can be pushed in smoothly.

As described above, the nozzle lance for water jet cleaning according to the embodiment of the present invention and another embodiment has the following structure, function and operation.

An ultra-thin tube having an outer diameter of about 6 mm is used as a lance to be inserted into a gap between the tube groups in the heat exchanger. Inside the lance, a narrow flow passage capable of supplying high-pressure water of about 700 kgf / cm ² is provided, and the lance has sufficient pressure resistance. A plurality of nozzles are fixed so as to be embedded in the side near the head of the lance.

When two nozzles are provided for one lance, the nozzles are mounted at positions 180 ° apart from each other in the circumferential direction of the lance. Further, the position of the nozzle is shifted with respect to the axis (longitudinal) direction of the lance. This is to ensure the strength of the lance that receives a high internal pressure.

The nozzle has a shape having a large radius at the inlet. The radius of curvature in this roundness is about 4 to 8 times the radius of the ejection hole. With the nozzle having such a shape, the jet extends in the axial direction without separation at the inlet of the nozzle, and the passing force is maintained to the downstream.

A plurality of lances are arranged in a row (in parallel) to form a multiple lance, which is treated as one set by one washing operator (operator). These lances are connected in parallel using a plate as a support member. The plurality of lances are mounted on the manifold at the base. The manifold joins a high-pressure hose fed from a high-pressure pump. When the distance between the fin tubes at the portion to be cleaned is smaller than the outer diameter of the lance, a plate material called a “guide bar” is inserted to widen the distance between the fin tubes and forcibly create a gap into which the lance can be inserted.

A water jet blows at high speed from a nozzle outlet of a lance inserted like an endoscope into a gap between the heat transfer tubes. Since this nozzle has a structure that suppresses unnecessary turbulence of the jet without causing separation by taking a large roundness (R portion) at the inlet portion, the core of the water jet extends in the axial direction, It becomes a state where it easily penetrates in the axial direction. This water jet is less likely to break up into droplets, and even when it reaches downstream, the momentum for pushing in the axial direction continues. Therefore, even if it hits any of the surface of the heat transfer tube base tube, the side surface of the fin, and the root of the fin, the power of the collision is strong and the attached rust is efficiently removed.

According to this embodiment, rust can be efficiently removed in a short time and with a small amount of water. Since the power of the impact of the water jet is strong, there is no need to increase the jet pressure of the jet unnecessarily. As a result, the heat transfer tubes are washed well, and the heat transfer performance of the heat exchanger is restored.

Next, a water jet cleaning nozzle lance according to still another embodiment of the present invention will be described with reference to FIGS.
This will be described in detail below. FIG.
Is drawn as a schematic sectional view in the axial direction (a structure on the same plane is not shown). The tip of the lance 14 is sealed. Two nozzle tips 15 are mounted on the side wall of the lance 14 so as to be shifted in the axial direction so that the two nozzle tips 15 are embedded. A large roundness is provided at the inlet of the nozzle tip 15 so that the high-pressure water 6 does not separate at the nozzle inlet. Jet hole 21 of nozzle tip 15
, A short straight portion 21b is provided near the outlet, and the outlet is machined with a counterbore 21a. With such a structure, a water jet having a strong penetrating force in the axial direction is ejected from the ejection hole 21, and even if the water jet contacts the fin 3, the ejection hole 21 is not deformed. Absent.

As shown in FIG. 12, two lances 14 are arranged in parallel. These two lances 14
Is supported by a plurality of support plates 22,
The base of the lance 14 is a high-pressure hose 2 for supplying high-pressure water 6.
5 is fixed to a manifold joint 24 which also serves as a connection with the joint 5. In this figure, a downward nozzle tip 15a, whose ejection hole faces obliquely downward, is attached to the upper lance 14, and one of the nozzle tips 15a (tip end) is located on the other side on this paper surface.
Further, a downward nozzle tip 15a on the base side of the lance 14
The water jets blow out toward the front side of the paper.

On the other hand, an upward nozzle tip 15b whose ejection hole faces obliquely upward is attached to the lower lance 14 in FIG. Each of the upward nozzle tips 15b on the base side blows water jets to the other side on the paper. Two lances 14
Is provided with a plate-shaped tip plate 23 having a rounded tip. When the gap between the heat transfer tubes (fin tubes) 1 is narrow, the gap is forcibly created as a so-called “pilot” so as to make it easy to pass through the lance 14.

FIG. 13 shows a state in which four water jets 16 are blown out from the nozzle lance for water jet cleaning according to the present embodiment and are blown against the heat transfer tube (fin tube) 1 for cleaning from the front end side of the lance. It is drawn as a perspective view. From the downward nozzle tip 15 a attached to the upper lance 14, a water jet 16 is spouted at a high speed in a diagonally downward direction in both the left and right directions, and is blown between the fins 3.

FIG. 14 is a perspective view of the structure of the nozzle lance for water jet cleaning according to the present embodiment, in particular, the configuration of the portion for blowing out the water jet, as viewed from obliquely above. The two lances 14 are supported by the support plate 22 substantially in parallel. The upper lance 14 is provided with a downward nozzle tip 15 a that blows the water jet 16 obliquely downward, and is displaced in the axial direction of the lance 14. Also,
On the lower lance 14, an upward nozzle tip 15a that blows the water jet 16 obliquely upward,
Also in this case, the nozzle tip is mounted at a position shifted in the axial direction of the lance 14. In FIG. 14, the tip plate 23 (FIG. 12) at the tip of the lance 14 is omitted.

FIG. 17 schematically illustrates a state in which the water jet blows obliquely downward and collides with the surface of the fin 3. The collision angle θ in this embodiment is approximately 35 °. According to such an oblique collision, a striking impact pressure as a vertical component and a shearing force as a horizontal component act on the rust (scale) 26 attached to the surface of the fin 3. The scale 26 is efficiently removed.

In practice, the scale 26 is pulverized, and most of it is shattered, but remains in the form of thin flakes.
It may come off the fin. The fins 3 are installed downward in order to sulfide the water droplets that have condensed by gravity. The function and operation illustrated in FIG. 17 is to remove the scale on the upper surface of the downward fin 3. However, this function alone cannot remove the scale 26 on the back side of the fin 3. Therefore, a water jet 16 that is obliquely upward is used.

FIG. 18 schematically illustrates a state in which a water jet blown obliquely upward from the nozzle tip 15 penetrates between the fins 3. Since the gap between the fins 3 is filled with water, the jetted water jet becomes a cavitation jet 28 accompanied by severe cavitation. Since the cavitation applies an impact force not only in the traveling direction of the jet 28 but also in the lateral direction, the scale attached to the back side of the fins 3 and the surface of the mother tube 2 is easily removed by the impact force due to the cavitation.

FIG. 19 shows actual results of water-washing operation, and shows a comparison between the prior art and the embodiment of the present invention in terms of the time required for water-washing operation. The washing time t on the vertical axis was made dimensionless by dividing by the washing time t ^* in the prior art. Therefore, the prior art is t /
t ^* = 1. According to the embodiment of the present invention, it can be seen that the washing time can be reduced to almost half. This is because the scale can be easily removed, and the washing operation can be completed within a short time.

If the washing time is short, the amount of water used can be reduced. FIG. 20 shows a comparison between the prior art and the embodiment of the present invention in the amount of water used for cleaning. The water consumption Qw on the vertical axis was made dimensionless by dividing by the water consumption Qw ^* in the prior art. Therefore, in the prior art, Qw / Qw ^* = 1. According to the embodiment of the present invention, Qw / Qw ^* is 0.44, and it can be seen that the amount of water used can be reduced to half or less compared to the conventional case. This effect greatly contributes not only to the reduction of the operation cost of the power prober (vacuum suction) vehicle but also to the reduction of the operation cost of the wastewater treatment plant.

Next, a configuration example of still another embodiment of the present invention will be described below with reference to FIGS. In the embodiment shown in FIGS. 13 and 14 described above, even with a double lance set in which the same two lances are combined, two nozzle tips provided in one lance are both obliquely downward or both downward. It was configured to blow out a diagonally upward water jet.

On the other hand, the configuration example shown in FIGS. 15 and 16 is a two-unit lance set in which two lances 14 are combined in parallel,
In this case, the water jet 16 from the upward nozzle tip 15b on the tip side is directed obliquely upward, that is, the water jet 16 penetrates between the fins, and the water jet 16 from the downward nozzle tip 15a on the root side of the lance 14 is inclined. The water jet 16 obliquely strikes the surface of the fin 3 downward.

On the other hand, the lower lance 14 is opposite to the upper lance, and the water jet 16 from the downward nozzle tip 15a provided on the tip side of the lance 14 is directed obliquely downward to the surface of the fin. Water jet 1
6 are obliquely collided with each other, and the water jet 16 from the upward nozzle tip 15 b on the base side of the lance 14 is configured to penetrate between the fins 3 obliquely upward. Here, it is common to the above-described embodiment that the upper and lower lances 14 are fixedly held by the support plate 22 so that the two lances 14 are parallel to each other.

As described above, if one jet is directed obliquely upward and the other jet is directed obliquely downward in the same lance, the reaction force acting in the bending direction of the lance can be canceled, and the lance has a strong durability. Is improved.

As described above, the nozzle lance for water jet cleaning according to still another embodiment of the present invention has the following configuration, function and operation.

The ejection holes of the nozzle tip mounted so as to be embedded in the side walls of the lance tube are (1) obliquely downward and (2) with respect to the lance shaft inserted into the heat transfer tube group of the heat exchanger.
Turn diagonally upward. In (1), the high-speed water jet blown from the nozzle against the surface of the fin which is attached to the mother pipe at a downward inclination hits the surface of the fin at a collision angle of 20 ° or more and 70 ° or less. The direction of the ejection hole of the nozzle tip is set as described above. In (2), the direction of the ejection hole of the nozzle tip is set so that the high-speed water jet enters the gap between the fins.

The above-mentioned (1) and (2) are combined and installed in the same lance, or the lances are arranged in parallel to form a double lance set. The nozzle tip is combined with the nozzle tip of the above (2) specification in another lance.

The thin tube type lance has a structure in which the tip is sealed and high pressure water is supplied inside. The nozzle tip is
In any of the specifications (1) and (2), the inlet portion is largely rounded, and at least two or more nozzles are mounted on the side of the lance tube. When a plurality of nozzle tips are provided in the same lance, the positions of the nozzle tips are shifted with respect to the axial direction of the lance. The lance is configured as one set by combining two or more lances, and is handled by one flushing operator (operator).

Here, the surface of the fin is 20
A water jet that collides with the fin at a collision angle in the range of not less than 70 ° and not more than 70 ° removes rust (scale) most efficiently. In an oblique collision under such conditions, the effect of pulverizing and removing rust is enhanced. This is because the vertical component of the impact on the fin acts as a compressive breaking force, while the horizontal component acts as a shear force to grind the rust.

The proper collision angle θ = 20 ° to 70 ° is the same as that in FIG.
As shown in FIG. 1, it is due to the additive effect of the vertical impact and shearing action. The shock effect increases with an increase in the collision angle θ, reaches a maximum at 90 °, and saturates. On the other hand, the shearing action decreases as the collision angle θ decreases. Looking at the additive effect of the shocking action and the shearing action, the collision angle θ = 20 ° to 70 ° is a condition that can substantially satisfy the predetermined cleaning effect.

The water jet that enters the gap between the fins becomes a high-speed water jet in the water because water accumulates in the semi-closed space between the fins and the mother pipe, and intense cavitation occurs between the fins. Since cavitation acts not only in the direction of travel of the jet but also in all directions, it removes not only the surface of the fin but also rust (scale) on the surface of the mother tube. According to the cabinet station generated on the side surface of the water jet, it is possible to simultaneously clean both sides of rust (scale) adhering to both inner surfaces of the two fins.

[0060]

According to the present invention, the heat transfer tube can be easily cleaned even in a narrow portion such as a gap between the heat transfer tubes. That is, it is possible to wash the inside of the heat exchanger with water. In the finned heat transfer tube, not only the deposits between the fins and the deposits at the roots of the fins but also the deposits on the fin surface that are most strongly involved in heat resistance can be efficiently removed. As a result, it becomes possible to wash the narrow part in the recessed position, and the heat transfer performance of the heat exchanger is sufficiently restored.

Further, since the injection pressure of the water jet does not need to be excessively increased (without using ultra-high pressure water), the power consumption (energy cost) can be kept low, and Without this, a sufficient washing effect can be obtained and high washing efficiency can be achieved.

Since the nozzle lance is lightweight and easy for an operator to operate, cleaning can be completed within a short period of time. Further, since the water used for the jet can be reduced, the cost required for wastewater treatment can be reduced.

In addition, the nozzle is hardly worn, in other words, has high durability, and can maintain high washing efficiency for a long time.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state in which a water jet is sprayed on a narrow portion in a heat exchanger by a water jet cleaning nozzle lance according to an embodiment of the present invention.

FIG. 2 is a diagram showing a structure of a water jet ejection part in a nozzle lance of the present embodiment.

FIG. 3 is a diagram showing a structure of a multiple lance according to the embodiment.

FIG. 4 is a view showing a state of spraying a water jet by a water jet cleaning nozzle lance according to the embodiment of the present invention.

FIG. 5 is a diagram showing a configuration for mounting the cleaning nozzle lance of the present embodiment in a narrow portion in the heat exchanger.

FIG. 6 is a view showing a configuration of a water jet cleaning nozzle lance according to another embodiment of the present invention.

FIG. 7 is a diagram schematically illustrating a phenomenon in a water jet ejection part of a cleaning nozzle lance of the present embodiment.

FIG. 8 is a view showing the results of actual high-pressure water washing work, and is a diagram that demonstrates the effect of implementing the present invention.

FIG. 9 is a view showing the results of actual high-pressure washing, and is a diagram that demonstrates the effect of implementing the present invention.

FIG. 10 is a view showing the results of actual high-pressure water washing work, and is a diagram that demonstrates the effect of implementing the present invention.

FIG. 11 is a view showing a structure of a water jet ejection part in a nozzle lance according to still another embodiment of the present invention.

FIG. 12 is a view showing a structure of a multiple lance according to still another embodiment of the present invention.

FIG. 13 is a cross-sectional view showing a water jet spraying state by a water jet cleaning nozzle lance according to still another embodiment of the present invention.

FIG. 14 is a sketch showing a state of spraying a water jet by a water jet cleaning nozzle lance according to still another embodiment of the present invention.

FIG. 15 is a cross-sectional view showing a state of spraying a water jet by a water jet cleaning nozzle lance according to a configuration example of still another embodiment of the present invention.

FIG. 16 is a sketch showing a state of spraying a water jet by a water jet cleaning nozzle lance according to a configuration example of still another embodiment of the present invention.

FIG. 17 is a view showing a water jet cleaning operation when using a nozzle lance according to still another embodiment of the present invention.

FIG. 18 is a view showing a water jet cleaning operation when using a nozzle lance according to still another embodiment of the present invention.

FIG. 19 is a view showing test results using a nozzle lance according to still another embodiment of the present invention, and demonstrating a cleaning effect.

FIG. 20 is a view showing test results using a nozzle lance according to still another embodiment of the present invention, and demonstrating a cleaning effect.

FIG. 21 is a view for explaining the basis of setting conditions in a water jet cleaning nozzle lance according to still another embodiment of the present invention.

FIG. 22 is a view showing a state in which a water jet is sprayed on a narrow portion in a heat exchanger by a conventional water jet cleaning nozzle lance.

FIG. 23 is a view showing the structure of a conventional nozzle lance for water jet cleaning.

FIG. 24 is a view showing a structure of a conventional water jet cleaning nozzle lance and a water jet formed by the lance.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat transfer tube (fin tube) 2 Main pipe 3 Fin 6 High pressure water 8 Heat transfer tube group 14 Lance 15 Nozzle tip 16 Guide bar 17 Water jet 18, 22 Support plate 19 Manifold 20, 25 High pressure hose

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F28G 9/00 B08B 9/02 D (72) Inventor Ikuhisa Hamada 2-4-1 Hamamatsucho, Minato-ku, Tokyo No. Babcock Hitachi Co., Ltd. (72) Inventor Tomio Fukumoto 6-9 Takaracho, Kure-shi, Hiroshima Prefecture Babcock Hitachi Co., Ltd. Kure Office (72) Inventor Shohei Akimoto 5-3 Takaracho, Kure-shi, Hiroshima Bab Hitachi engineer Nearing Co., Ltd. (72) Inventor Atsushi Furukawa 6-9 Takara-cho, Kure-shi, Hiroshima Babcock Hitachi Co., Ltd. (72) Inventor Hiroaki Ichikawa 6-9 Takara-cho, Kure-shi, Hiroshima Bubcock Hitachi Kure, Inc. (72) Inventor Hideki Yamauchi 6-9, Takara-cho, Kure-shi, Hiroshima Babcock-Hitachi Kure Plant (72) Inventor Hiroki Kawashima 6-9, Takaracho, Kure-shi, Shima Prefecture Babcock Hitachi Kure Factory (72) Inventor Tadaaki Mizoguchi 3-36, Takaracho, Kure-shi, Hiroshima Bubcock Hitachi Kure Research Laboratory F-term (reference) 3B116 AA13 AB54 BB23 BB33 BB47 BB55 BB90 3B201 AA13 AB54 BB23 BB33 BB47 BB55 BB90 BB92 CB01 3K061 QC36 QC38

Claims (12)

[Claims] 1. A water jet cleaning apparatus comprising: a tubular lance through which high-pressure water flows, and a water jet injection nozzle tip provided in the lance, wherein the water jet is sprayed on a group of heat transfer tubes to perform cleaning. A water jet, wherein the lance comprises a thin tube and a long lance which can be inserted into a gap between the heat transfer tube groups, and a plurality of the nozzle tips are mounted on a side wall of the lance. Nozzle lance for cleaning. 2. The nozzle lance for water jet cleaning according to claim 1, wherein, when the number of the nozzle tips is two, each nozzle tip is provided at a position 180 ° away from the circumferential direction of the lance, and each of the nozzle tips is provided. A water jet cleaning nozzle lance, which jets a water jet from a nozzle in opposite horizontal directions. 3. The nozzle lance for water jet cleaning according to claim 1, wherein each nozzle tip is disposed so as to be shifted with respect to the axial direction of the lance. 4. The nozzle lance for water jet cleaning according to claim 1, wherein a radius of curvature of a flow path at an inlet of the nozzle tip is:
A nozzle lance for cleaning a water jet, wherein the lance is selected from a range of four times or more and less than eight times the radius of the injection hole. 5. The water jet cleaning nozzle lance according to claim 1, wherein a plurality of lances are connected by a fixing member to form the lances in parallel to form a set of lances. A nozzle lance for water jet cleaning, wherein a root side of the set of lances is mounted on a manifold, and high-pressure water is supplied to the manifold. 6. A water jet cleaning apparatus comprising: a tubular lance through which high-pressure water flows, and a nozzle tip for water jet injection provided in the lance, wherein the water jet is sprayed onto a group of heat transfer tubes for cleaning. A method of cleaning a heat transfer tube using a nozzle lance, wherein the lance is a thin tube and a long lance that can be inserted into a gap between the heat transfer tube groups, and a plurality of nozzle tips are mounted on a side wall of the lance. Before inserting the water jet cleaning nozzle lance into the heat transfer tube group, insert a guide member larger than the diameter of the lance into the gap between the heat transfer tube group, and the lance moves through the heat transfer tube group. After forcibly creating a gap that can pass through, the lance is inserted into the gap of the heat transfer tube group and a water jet is blown to wash the heat transfer tube group. A method of cleaning the heat transfer tube using a water jet cleaning nozzle lance to. 7. The water jet cleaning nozzle lance according to claim 1, wherein the water jet strikes the water jet at an angle of not less than 20 ° and not more than 70 ° with respect to the surface of the fin provided on the heat transfer tube. A nozzle lance for cleaning water jets, wherein the nozzle tip is installed so as to face the lance. 8. The water jet cleaning nozzle lance according to claim 1, wherein the nozzle tip is oriented so that a water jet penetrates between fins of the heat transfer tube. A lance for cleaning a water jet, which is set up with respect to the lance. 9. The water jet cleaning nozzle lance according to claim 1, wherein the water jet strikes the water jet at an angle of 20 ° to 70 ° with respect to the surface of the fin provided on the heat transfer tube. A lance on which the nozzle tip is installed, and a lance on which the nozzle is installed such that the water jet penetrates between the fins of the heat transfer tube. Are assembled in parallel to form a set of lances. 10. The nozzle lance for water jet cleaning according to claim 1, wherein the water jet impinges on the surface of the fin provided on the heat transfer tube at an angle of 20 ° or more and 70 ° or less. One of the nozzle tips is installed with respect to the lance so as to be oriented, and the injection hole is oriented such that a water jet penetrates between the fins of the heat transfer tube. A nozzle lance for water jet cleaning, wherein another nozzle tip of the nozzle tips is installed with respect to the lance. 11. The water jet cleaning nozzle lance according to claim 10, wherein the lances are assembled in parallel to form a set of lances. 12. The nozzle lance for water jet cleaning according to claim 7, 8 or 10, wherein each nozzle tip is displaced with respect to the axial direction of the lance. .