JPH04298257A - Nozzle for removing scale - Google Patents

Abstract

PURPOSE:To reduce the thickness of the jet flow injected from an injection port and to increase the collision force per unit area so as to efficiently remove scale by providing flow regulating passages of the same diameter or approximately the same diameter over the entire length in the mid-way positions in the axial central direction of throttling passages on the same center over the length longer than the diameter of the flow regulating passages. CONSTITUTION:The two throttling passages B, C which are gradually smaller in diameter toward the injection port C1 side are provided on the same center between the flow regulator-contg. passage A in which the flow regulator 4 is mounted and the injection port C1. The flow regulating passages D, E of the same diameter or approximately the same diameter over the entire length are provided on the same center between these throttling passages B and C over the length longer than the diameter of these passages D, E. Consequently, the fluid regulated by passing the flow regulator- contg. passage is prevented from causing turbulence again at the time of passing the throttling passages while the flow velocity of this fluid is increased by the throttling passages. The thickness of the jet flow injected from the injection port is reduced in this way, by which the collision force per unit area is increased and the scale is efficiently removed.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a scale removal nozzle that is used when removing scale from the surface of a rolled steel plate by injecting a band of high-pressure fluid (water, etc.) onto the surface of the rolled steel plate. Specifically, a constriction passage whose diameter gradually decreases toward the injection port is provided concentrically between the rectifier internal passage in which the rectifier is installed and the injection port, and the injection port is formed on the tip surface of the nozzle. This relates to a scale removal nozzle that opens at the bottom of the groove.

0002

[Prior Art] As the scale removal nozzle described above, a series of throttle passages whose diameter gradually decreases toward the injection port are provided concentrically between the rectifier internal passage in which the rectifier is installed and the injection port. something is known (e.g. Special Publication 1-11)
(See Publication No. 1464).

0003

[Problems to be Solved by the Invention] The conventional scale removal nozzle described above has a series of apertures whose diameter gradually decreases toward the injection port in order to increase the flow velocity of the fluid after it has passed through the passage inside the rectifier and been rectified. Although it has a passageway,
As the rectified fluid passes through the throttle passage, it tends to become turbulent again, and as a result, the thickness of the jet flow injected from the injection port becomes thicker, and the collision force per unit area becomes smaller, making it more efficient. There is a drawback that scale cannot be removed. The present invention has been made in view of the above-mentioned circumstances, and by devising the shape of the throttle passage, the flow velocity of the fluid after passing through the rectifier internal passage and being rectified can be increased in the throttle passage, and the flow rate of the fluid can be increased. The purpose of the present invention is to provide a scale removal nozzle that can prevent the flow from becoming turbulent again as it passes through a passage.

0004

[Means for Solving the Problems] A characteristic configuration of the present invention for achieving the above object is that in the scale removal nozzle described above, a diameter of the same diameter or The rectifying passages having approximately the same diameter are provided concentrically over a length longer than the diameter of the rectifying passage, and this configuration provides the following effects.

[0005]

[Operation] The fluid becomes turbulent again while increasing its flow velocity as it passes through the throttle passage on the upstream side of the rectifying channel.
The flow flows into a rectifying passage with the same diameter or approximately the same diameter over the entire length and is once rectified.At the same time, the existence of the throttle passage on the downstream side of the rectifying passage acts as resistance, increasing the pressure, and the flow is rectified in the rectifying passage. The fluid whose flow velocity and pressure have been increased flows into the throttle passage portion on the downstream side of the rectifying passage, where the flow velocity is further increased, and then is injected from the injection port.

[0006]

[Effects of the Invention] Although the flow velocity of the fluid that has been rectified after passing through the rectifier internal passage is increased in the throttle passage, it is possible to prevent the flow from becoming turbulent again as it passes through the throttle passage, as much as possible.
As a result, the thickness of the jet stream injected from the injection port becomes thinner, the collision force per unit area increases, and scale can be removed efficiently.

[0007]

[Example] Next, an example of the present invention will be shown. Figure 1 shows a scale removal nozzle for removing scale from the surface of a rolled steel plate by spraying high-pressure water onto the surface of the rolled steel plate. A first passage forming member 1, a cylindrical second passage forming member 9,
The injection passage forming member 3 is screwed and connected in the order described. The first passage forming member 1 includes a rectifier interior passage A in which a rectifier 4 is installed, a first throttle passage B that follows the downstream end of the rectifier interior passage A, and a first throttle passage B that follows the downstream end of the first throttle passage B. The rectifying passage D is formed in such a manner that the passage axes X thereof are located on the same straight line.

The rectifier internal passage A is formed in a shape (that is, cylindrical) with the same diameter over its entire length, and the diameter of the first throttle passage B gradually decreases linearly toward the downstream side over its entire length. formed in the shape (i.e. truncated cone),
The first rectifying passage D has a shape (
In other words, it is formed into a cylindrical shape. To give actual numerical values of the shape and dimensions of the first throttle passage B, in this example, the passage length is 41.2 mm, the upstream end diameter is 12.9 mm, the downstream end diameter is 7.6 mm, and the passage circumference with respect to the passage axis X. Inclination angle θ of the surface
is approximately 3 degrees and 45 minutes. In addition, in this example, the length of the first rectifying passage D is 2.8 m.
m, the diameter is 7.6 mm.

As shown in FIG. 2, the rectifier 4 has a plurality of rectifying plates 4A arranged radially along the passage axis X and having a length slightly longer than the entire length of the passage A inside the rectifier. The rectifier 4 has a conical protrusion 4B integrally arranged and connected on both end faces in the direction of the passage axis X at the center thereof, and the downstream end side of the rectifier 4 enters into the first throttle passage B. There is. Therefore, the rectifier interior passage A of the rectifier plate 4A
The outer circumferential edge of the part that is internally installed in the rectifier is formed in a posture parallel to the passage axis X so that its entire length comes into contact with the circumferential surface of the rectifier internal passage A, and the part that enters into the first throttle passage B. The outer peripheral edge of is formed in an inclined position such that its entire length comes into contact with the circumferential surface of the first throttle passage B so that the downstream side approaches the passage axis X. The actual length of the rectifier plate 4A of the rectifier 4 is 16 mm in this embodiment when the first throttle passage B is formed with the above-mentioned real value. As shown in FIG. 3, the filter 2 is cap-shaped, and has a plurality of vertical slits 2A distributed at equal intervals in the circumferential direction from near the tip to near the bottom of a dome-shaped plate. The first passage forming member 1 is screwed onto the first passage forming member 1 so as to cover the upstream side of the rectifier 4.

The second passage forming member 9 is a first rectifying passage D.
A second rectifying passage E is formed concentrically with the passage axis X, and like the first rectifying passage D, this second rectifying passage E has a shape with the same diameter over its entire length (that is, a circular shape). The first rectifying passage D and the second rectifying passage E are connected in series by being threadedly connected to the downstream end of the first passage forming member 1. To give an actual value of the shape and dimensions of this second rectifying passage E, in this example, the passage length is 46.8 m.
m, and the diameter is 7.6 mm, similar to the first rectifying passage D.

The injection passage forming member 3 has a nozzle case 3A that is threadedly connected to the downstream end of the second passage forming member 9, and is press-fitted into the nozzle case 3A and is prevented from coming off by a stepped portion 3b. A nozzle tip 3B made of cemented carbide with excellent wear resistance is fixed to its tip, and a nozzle case 3
A groove 3a is formed along the nozzle diameter direction on the nozzle tip surface formed by the nozzle case 3A tip surface and the nozzle tip 3B tip surface. The injection port C1 of the formed injection passage C2 opens at the bottom of this groove 3a. The bush 3C is provided with a second restriction passage C that continues to the downstream end of the second rectification passage E, and a third rectification passage F that extends between the downstream end of the second restriction passage C and the upstream end of the injection port C1. The passage axes X are formed on the same straight line, and the second throttle passage C
is formed in a shape (that is, a truncated conical shape) whose diameter gradually decreases linearly toward the downstream side over its entire length, and the third rectifying passage F is formed in a shape that has an equal diameter over its entire length (that is, a cylindrical shape). is formed. To give actual values of the shapes and dimensions of the second throttle passage C, the third rectification passage F, and the injection passage C2, in this embodiment, the passage length of the second throttle passage C is 12.5 mm, and the upstream end diameter is 7. .6mm, downstream end diameter is 7
．． 1 mm, the inclination angle α of the passage peripheral surface with respect to the passage axis X is approximately 1 degree 8 minutes, and the passage length of the third rectifying passage F is 10 mm.
0 mm, the diameter is 7.1 mm, and the diameter of the portion of the injection passage C2 that follows the third rectification passage F is 7.1 mm. Furthermore, the passage length and downstream end diameter of the second throttle passage C, the inclination angle α of the passage peripheral surface with respect to the passage axis X, the passage length and diameter of the third rectifying passage F, and the diameter of the injection passage C2 are based on the fluid flow. It is desirable to change it appropriately depending on the flow rate.

The scale removal nozzle is inserted into an adapter 6 attached to the main pipe 5 in the form of a branch pipe, with the filter 2 positioned inside the main pipe 5, and a packing is attached to the end face of the adapter 6. A flange 3A1 for regulating the position in the axial direction and a protrusion 3A2 for preventing rotation that engages with a groove 6a formed on the inner circumferential surface of the adapter 6 are integrally connected to the nozzle case 3A, A cap nut 8 screwed onto the adapter 6 presses the flange 3A1 against the end surface of the adapter 6 to fix it.

Next, an experimental example will be shown. In each experiment, as shown in FIG. 12, the header 10 is used as the main pipe 5, and the scale removal nozzle is attached via the adapter 6. 2A number N, slit length P in the direction along the passage axis X, slit width M, total rectification passage length L which is the sum of the passage length of the first rectification passage D and the passage length of the second rectification passage E. Change the injection pressure to 120
Kgf/cm2, injection flow rate is 106.6 liters/mi
n, the jet stream from the nozzle is made to collide with the lead plate 13 under the basic condition that the jet distance is 300 mm, and the collision of the jet stream causes the lead plate 1 to collide with the lead plate 13.
From the depth of the groove 14 formed on 3, measure the distribution state of the collision force in the jet flow thickness T direction and the maximum collision force Fmax (unit: gf) at a 7 mm wide part at the center of the width direction of the jet flow. did. The maximum collision force Fmax is a size per circular area of 1 mmφ, and is an average value of six test results under the same conditions.

[0014] In FIGS. 6 to 8, N=18, P=35
．． 4mm, M=1.0mm, and Figure 6 shows the case where L=2
．． 8mm, L=27.8mm in Figure 7, L=4 in Figure 8
Distribution state of collision force and maximum collision force Fm in case of 9.6mm
This is the measurement result of ax (unit gf). Figures 9 to 11
shows the case where N=12, P=30.1mm, M=1.5mm, FIG. 9 shows the case where L=2.8mm, and FIG. 10 shows the case where L=27
．． 8mm. FIG. 11 shows the measurement results of the collision force distribution state and the maximum collision force Fmax (unit: gf) when L=49.6mm. In FIG. 12, the measurement results of the maximum collision force Fmax are plotted with the total rectification passage length L (unit: mm) on the horizontal axis and the maximum collision force Fmax (unit: gf) on the vertical axis. From these measurement results, the maximum collision force Fmax becomes larger as the total rectification passage length L becomes longer.Moreover, by narrowing the slit width M and increasing the number N of vertical slits 2A, It can be seen that the longer the slit length P becomes, the greater the maximum collision force Fmax becomes.

[0015] Note that although reference numerals are written in the claims for convenience of comparison with the drawings, the present invention is not limited to the structure of the accompanying drawings by such entry.

[Brief explanation of drawings]

[Figure 1] Longitudinal side view

[Figure 2] Perspective view of rectifier

[Figure 3] Plan view from the filter side

[Figure 4] Plan view from the nozzle tip side

[Figure 5] Schematic diagram of experimental equipment

[Figure 6] Graph showing impact force distribution in the jet flow thickness direction

[
Figure 7: Graph showing impact force distribution in the jet flow thickness direction

[Figure 8] Graph showing impact force distribution in the jet flow thickness direction

[Figure 9
】Graph showing impact force distribution in the jet flow thickness direction

[Figure 10
】Graph showing impact force distribution in the jet flow thickness direction

[Figure 11
】Graph showing impact force distribution in the jet flow thickness direction

[Figure 12
] Graph showing maximum collision force Fmax

[Explanation of symbols]

3a Groove 4 Rectifier A Rectifier interior passage B Throttle passage C Throttle passage C1 injection port D Rectification passage E Rectification passage X Passage axis

Claims (1)

[Claims] 1. The injection port (C1) is located between the rectifier interior passage (A) in which the rectifier (4) is installed and the injection port (C1).
The diameter of the throttle passage (B) gradually decreases toward the C1) side.
C) are provided concentrically, and the injection port (C1) is opened at the bottom of a groove (3a) formed on the nozzle tip surface.
), (C), there is a rectifying passage (D), (E) with the same diameter or approximately the same diameter over the entire length in the middle position in the direction of the passage axis (X). A scale removal nozzle characterized by being provided concentrically over a longer length.