JP2009228705A - Merging porion structure of piping - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a merging portion structure obtaining a flow rate commensurate to the power of a pump. <P>SOLUTION: The merging portion structure of piping connects a branch pipe 20 in which a second fluid flows to a main pipe 10 in which a first fluid flows. To the first fluid of the main pipe 10, the second fluid is made to flow from an outflow port 21 of the branch pipe 20 and mixed. An expanding portion 22 is provided immediately before the outflow port 21 of the branch pipe 20, thereby expanding a diameter immediately before the outflow port 21 in the branch pipe 20 to be equivalent to the diameter of the main pipe 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a joining part structure of piping for connecting piping and mixing fluid.

Piping is installed at various factories to transport various fluids.
In the iron and steel industry, various fluids such as combustion gas and circulating water are transferred by pipes. To give a specific example, as shown in FIG. In order to remove the generated iron oxide (hereinafter referred to as scale), pressurized water is sprayed on the steel plate 101 from the spray nozzle 102 or the like, or the work roll 103 of the rolling mill is cooled from the spray nozzle 102 or the like. For example, water is supplied to the work roll 103.

  Further, the water used in the hot rolling step 100 is divided into rough mill water and finishing mill water depending on the location of use. These are collectively called mill ring water. As shown in FIG. 5, the mill water is collected by the sluice 104, impurities such as scale contained in the water are removed from the bit 105 through the settling tank 106 and the filter 107, and sent to the water supply tank 108. Thereafter, the water from which impurities have been removed is recycled by being returned to the mill. Further, the removed impurities are concentrated in the concentration tank 109, made into a slurry, and applied to the dehydrator 110. A part of the compressed water, the concentrated tank supernatant, and the circulating water of the dehydrator 110 is discharged out of the system through the drainage equipment 111 as blow water. And in order to transfer these water, the pipe | tube which was made to join and branch appropriately is installed in the factory. Further, the water is transferred by a pump 112 appropriately disposed on the pipe.

By the way, in order to join with piping, the T-shaped joining pipe 121 as shown in FIG. 6 may be used. However, since the pressure loss (hereinafter referred to as pressure loss) of the fluid flowing through the branch pipe 132 connected to the main pipe 131 is large in the T-shaped joining pipe 121, a Y-shaped joining pipe 122 as shown in FIG. 7 is used. There are many cases. In the case of the Y-shaped joining pipe 122, the pressure loss of the branch pipe 132 differs depending on the joining angle between the main pipe 131 and the branch pipe 132 (the angle formed by the central axis of the main pipe 131 and the central axis of the branch pipe 132). The smaller the branch pipe 132 is tilted to the upstream side of the main pipe 131, the smaller the pressure loss of the branch pipe 132 becomes.
However, even in the Y-shaped merging pipe 122 that is frequently used in this manner, when the flow rate of the main pipe 131 is overwhelmingly higher than the flow rate of the branch pipe 132, the fluid flowing through the branch pipe 132 is pushed against the fluid flowing through the main pipe 131. There is a problem that the flow rate according to the capacity of the pump cannot be obtained.
The subject of this invention is making it the confluence | merging part structure from which the flow volume according to the capability of a pump is obtained.

In order to solve the above-described problem, the pipe junction part structure according to claim 1 according to the present invention is configured such that a branch pipe through which a second fluid flows is connected to a main pipe through which the first fluid flows, In the junction structure of a pipe that causes the second fluid to flow out from the outlet of the branch pipe and mix it with the first fluid of the pipe, the diameter immediately before the outlet in the branch pipe corresponds to the diameter of the main pipe It is characterized by being expanded to.
Moreover, the junction part structure of the pipe according to claim 2 according to the present invention is the junction part structure of the pipe according to claim 1, wherein an enlarged pipe is provided immediately before the outlet of the branch pipe. The diameter just before the outflow port is enlarged to the diameter of the main pipe.

  According to the present invention, by increasing the diameter of the branch pipe just before the outlet to the main pipe diameter, the amount of outflow from the branch pipe to the main pipe can be increased, and the flow rate according to the capacity of the pump can be obtained. Can do.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.
(Constitution)
FIG. 1 shows a junction part structure of a pipe to which the present invention is applied.
As shown in FIG. 1, the junction structure of the pipe connects the branch pipe 20 through which the second fluid flows to the main pipe 10 through which the first fluid flows in order to mix the second fluid with the first fluid. ing. Here, the 1st and 2nd fluids are circulating water etc., if piping is arranged in the steel industry.

A diameter D1 upstream of the outlet 21 of the branch pipe 20 is smaller than a diameter D2 of the main pipe 10, and a junction angle between the main pipe 10 and the branch pipe 20 (main pipe 10) at a connection portion between the main pipe 10 and the branch pipe 20. Angle θ) between the central axis of the branch pipe 20 and the central axis of the branch pipe 20 is an angle at which the branch pipe 20 falls to the upstream side of the main pipe 10.
Further, in the branch pipe 20, the diameter D <b> 3 immediately before the outlet 21 is enlarged to the diameter D <b> 2 of the main pipe 10. Specifically, by providing an enlarged portion (diffuser) 22 in the branch pipe 20 having a diameter D1 smaller than the diameter D2 of the main pipe 10, the diameter D3 immediately before the outlet 21 including the outlet 21 is changed to the main pipe 10. Is expanded (expanded) to a diameter D2.
(Function and effect)
The action and effect are as follows.

As described above, in the junction structure of the pipe, the second fluid is connected to the first fluid in the main pipe 10 by connecting the branch pipe 20 through which the second fluid flows to the main pipe 10 in which the first fluid is flowing. The fluid is discharged from the branch pipe 20 and mixed.
Then, the diameter of the junction point with the main pipe 10 in the branch pipe 20, that is, the diameter of the connecting portion to the main pipe 10 is enlarged immediately before the outlet 21, so that the first flow out of the branch pipe 20 to the main pipe 10 occurs. The flow rate of the second fluid can be increased.

  As shown in FIG. 1, the first fluid of the main pipe 10 is the second fluid of the branch pipe 20 at the connection portion between the main pipe 10 and the branch pipe 20, that is, in the vicinity of the end surface (outflow port 21) of the branch pipe 20. It is flowing to involve. For example, the flow of the main pipe 10 is separated from the outer periphery of the outlet 21 of the branch pipe 20, and the outlet 21 of the branch pipe 20 becomes negative pressure due to the separation, and the second fluid of the branch pipe 20 is caused by the negative pressure. The tube 10 is entrained in the first fluid.

For this reason, as described above, the branch pipe 20 is enlarged immediately before the outflow port 21 to increase the pipe cross-sectional area of the branch pipe 20, so that the first fluid caught in the first fluid flow in the main pipe 10 can be obtained. The flow rate of the second fluid can be increased.
Further, at the connecting portion between the main pipe 10 and the branch pipe 20, the outlet 21 at the end of the branch pipe 20 connected to the main pipe 10 is set as the merging angle θ such that the branch pipe 20 falls to the upstream side of the main pipe 10. The second fluid in the branch pipe 20 is more effectively involved in the flow of the first fluid in the main pipe 10 by being directed downstream in the pipe 10.

Next, let us examine the pressure loss at the junction of the pipes. The pressure loss (loss head) h at the junction of the pipes can be expressed by the relationship shown in the following formula (1).
h = ζ · v ² / (2 · g) (1)
Here, ζ is a pressure loss coefficient. The pressure loss coefficient is a value used for calculating the pressure loss received by the fluid flowing in the pipe. Further, v is a flow velocity in the branch pipe, and g is a gravitational acceleration. According to the equation (1), the pressure loss h decreases as the pressure loss coefficient ζ decreases.

Figure 2 is a flow ratio after the confluence, i.e. the flow rate _{Q 2} of the branch pipe 20, the flow rate _{Q 2} of the branch pipe 20 is flow _Q 3 after merged in the flow rate to _{Q 1} mains _{10 (= Q 1 + Q 2} ) and the When the flow rate ratio Q ₁ / Q ₃ , which is the ratio, is 0.1 (Q ₁ / Q ₃ = 0.1), the cross-sectional area A ₂ of the enlarged diameter portion 22 of the branch pipe 20 and the cross-sectional area A of the main pipe 10 _The change of the pressure loss coefficient when the cross-sectional area ratio A ₂ / A ₁ , which is a ratio to ₁ , is changed is shown. FIG. 3 shows the pressure when the cross-sectional area ratio A ₂ / A ₁ is changed when the flow rate ratio Q ₁ / Q ₃ is 0.5 (Q ₁ / Q ₃ = 0.5). Shows the change in loss factor. 2 and 3, the merging angle θ is used as a parameter.

As shown in FIGS. 2 and 3, the closer the cross-sectional area ratio A ₂ / A ₁ is to 1, that is, the closer the diameter D 3 immediately before the outlet 21 of the branch pipe 20 is to the diameter D 2 of the main pipe 10, the junction point. And the pressure loss coefficient of the fluid at the junction is reduced.
From such a result, the pump connected to the pipe can be operated at a discharge pressure closer to the original capacity, and the amount of inflow from the branch pipe 20 to the main pipe 10 can be increased.
In addition, the said embodiment can also be implement | achieved by the following structures.
That is, in the said embodiment, although the confluence | merging of the liquid was demonstrated, it is not limited to this, This invention is applicable also when using fluids, such as gas and a multiphase fluid.

(Example)
An example is as follows.
1 is used, and the main pipe 10 is an SGP pipe (carbon steel pipe for piping) having an outer diameter (diameter) 250A, and the branch pipe 20 is an outer diameter in front of the diffuser. (D4) 150A, SGP pipe with outer diameter (D3) 250A is used after the diffuser. On the other hand, as a comparative example (conventional example), the joining portion structure of the pipe is changed to the joining portion structure shown in FIG. 6 (T-shaped) or FIG. 7 (Y-shaped), and the main pipe 131 has an outer diameter (diameter name). ) A 250 A SGP pipe is used, and an SGP pipe having an outer diameter of 150 A is used as the branch pipe 132. In the case of applying the present invention (FIG. 1) and the comparative example, the pump capacity of the main pipe is 180 m ³ / h with a flow rate of 40 m, and the pump capacity of the branch pipe is 20 m ³ / h with a flow rate of 35 m. is there.
In the case of the T-shaped joining pipe 121 as shown in FIG. 6, the actual flow rate of the branch pipe 132 is 5 m ³ / h. As described above, since the flow rate of the main pipe 131 is overwhelmingly higher than the flow rate of the branch pipe 132, the fluid of the branch pipe 132 is pushed against the fluid of the main pipe 131 and is difficult to join. It seems to be the cause.

In the case of the Y-shaped joining pipe 122 shown in FIG. 7, the actual flow rate of the branch pipe was 9 m ³ / h, although the flow rate increased compared to the case of the T-shaped joining pipe 121. As described above, this is because the flow rate of the main pipe 131 is overwhelmingly higher than the flow rate of the branch pipe 132 as in the case of the T-shaped joining pipe 121, so that the fluid of the branch pipe 132 becomes the fluid of the main pipe 131. This is thought to be due to the fact that it is difficult to join due to defeat.
On the other hand, when the present invention is applied (in the case of the merging portion structure shown in FIG. 1), the actual flow rate of the branch pipe 20 is 12 m ³ / h, which is a comparative example (T-shaped merging tube, Y-shaped character). The flow rate is higher than that of the type merge pipe).

It is a figure which shows the junction part structure of piping of embodiment of this invention. FIG. 6 is a characteristic diagram showing the relationship between the cross-sectional area ratio A ₂ / A _{1, the} merging angle and the pressure loss coefficient ζ when the flow rate ratio Q ₁ / Q ₃ = 0.1. FIG. 6 is a characteristic diagram showing the relationship between the cross-sectional area ratio A ₂ / A ₁ and the merging angle and the pressure loss coefficient ζ when the flow rate ratio Q ₁ / Q ₃ = 0.5. It is the figure used for description of the process which removes the iron oxide on the surface of a steel plate with a spray nozzle in the process of hot rolling. It is a figure which shows the example of piping which implement | achieves the process of hot rolling. It is a figure which shows the T-shaped joining pipe which is the joining part structure of the conventional piping. It is a figure which shows the Y-shaped joining pipe which is the joining part structure of the conventional piping.

Explanation of symbols

  10 main pipes, 20 branch pipes, 21 outlet, 22 enlarged part, D1 branch pipe diameter, D2 main pipe diameter, D3 enlarged part diameter

Claims (2)

A branch pipe through which the second fluid flows is connected to the main pipe through which the first fluid is flowing, and the second fluid flows out from the outlet of the branch pipe and is mixed with the first fluid in the main pipe. In the junction structure of piping,
A junction structure of a pipe, wherein a diameter of the branch pipe immediately before the outlet is enlarged to a diameter of the main pipe.   The pipe according to claim 1, wherein a diameter of the branch pipe immediately before the outlet is enlarged to a diameter corresponding to a diameter of the main pipe by providing a pipe diameter enlarged portion immediately before the outlet of the branch pipe. Confluence part structure.

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