JPH0393B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a jet mixer as a type of flow mixer or line mixer.

[Conventional technology]

Water heaters, heating equipment, etc. that mix two fluids using the mixing effect of continuous fluid circulation.
In jet mixers used for reactor jackets, reflux heating of heat exchangers, showers, etc., the third method has conventionally been implemented as a device for preventing the water hammer phenomenon that often occurs in the jet mixer or in a system equipped with the jet mixer. As shown in the figure, a water hammer in the fluid chamber is created by inserting an insert C such as a fibrous metal thin wire, a metal spring, or a small metal particle into the fluid chamber formed between the main body 5 and the injection chamber 6. It is prevented. In a typical jet mixer, the main body 5
A flow path A whose cross-sectional area is gradually reduced and then gradually expanded is provided along the center line of the injection pipe inserted between the inlet port 1 and the outlet port 2, and the fluid to be supplied is passed through the flow path A. A fluid (gas or liquid) that is mixed at high speed is blown through the small hole a, mixed well, and then sent out from the outlet 2.

[Problem that the invention seeks to solve]

However, if the feed fluid is decreased, it becomes impossible to flow through the flow path A at a high velocity. The feed fluid, which cannot flow at such a high velocity, and the fluid blown through the small holes a are sent out from the outlet 2 without being mixed well. When the fluid to be mixed is steam, when the fluid is well mixed, the volume of the steam is reduced to the volume of the liquid, but the two fluids (steam and liquid) sent out without being well mixed are connected to the main body. When the pipe is sent out into the pipe, the pressure inside the pipe increases rapidly because there is no space around the pipe to accommodate the increased volume, and this rapidly increased volume has no place to escape, causing the inlet and Water suddenly flows back into the air inlet, causing water hammer.

If this water hammer cannot be stopped urgently, the equipment itself and the equipment will be damaged. Furthermore, even if the equipment is temporarily spared from damage, the water hammer cannot be stopped unless the steam that causes the water hammer to occur is stopped. Stopping the steam means stopping the operation, at least temporarily, and you cannot avoid damage caused by repeated occurrences of water hammer.

Damage to the main body of the equipment and equipment, as well as suspension of operation,
This will cause great damage to those using this facility.

[Means for solving problems]

The present invention aims to eliminate the above-mentioned drawbacks of the jet mixer body and device, and to provide a device designed to eliminate pressure loss in the bench lily flow path within the body. In the jet mixer, the jet mixer has a built-in bench lily type flow path between the delivery ports of the feeding fluid, and is provided with a jet mixing means for mixed fluid over a diverging flow path portion of the bench lily type flow path. Separately, a bypass pipe is provided that connects the inlet and the outlet in the shortest distance, and the bypass pipe is configured to
It is characterized by having a cross-sectional area in a range that exceeds the area obtained by subtracting the area of the minimum cross-sectional portion of the bench lily-shaped flow path from the cross-sectional area of the feed pipe of the feed fluid and is equal to the cross-sectional area of the feed pipe. A jet mixer with a bypass mechanism is constructed, which has great effects in preventing the occurrence of water hammer, simplifying the device design, and improving the economic efficiency of the equipment.

〔Example〕

The present invention will be explained below with reference to FIG. 1, which shows a cross section of a schematic configuration of an embodiment of a jet mixer according to the present invention.

The jet mixer main body 5 consists of a convergent flow path portion, a throat portion, and a diverging flow path portion between an inlet 1 and an outlet 2 that are aligned on the longitudinal axis of the main body and are in contact with the feed pipe 3 of the feed fluid. It has a built-in injection pipe 6 that forms a bench-lily type flow path A, and a fluid chamber formed between the main body 5 and the injection pipe 6 is filled with a fibrous insert C. 9 is a mixed fluid inlet;
An injection passage 10 formed of a large number of small holes a is provided on the wall of the injection pipe 6 and is inclined in the flow direction of the feed fluid.

The characteristic structure of this invention is that the inlet port 1
A bypass pipe 4 having a bypass flow path B that connects the two in the shortest distance is disposed between the vent lily type flow path A and the outlet port 2, and the cross-sectional area of the bypass pipe 4 is It is defined as a value in the range between the cross-sectional area of the same diameter as the feed pipe 3 and the area obtained by subtracting the cross-sectional area of the throat portion having the smallest cross-section of the bench-lily flow path A from the cross-sectional area. Note that the bypass pipe inlet is indicated by 7, and the bypass pipe outlet is indicated by 8.

[Effect]

Initially, the feed fluid is supplied to the inlet 1 and the bypass pipe inlet 7.
The pipes naturally separate into two and rejoin at the outlet 2 and the bypass pipe outlet 8. By installing this bypass pipe, conventionally, when the feed fluid was allowed to flow only through the flow path A whose cross-sectional area was gradually reduced and then gradually expanded, it became a resistance and was accompanied by a pressure loss. Since it separates into a bypass pipe with extremely low resistance, the feed fluid flows through the jet mixer without experiencing pressure loss.

Next, when steam (mixed fluid) is sent from the inlet 9 and mixed with the fluid that has flowed into the flow path A among the supplied fluids, the steam is
Since the small holes a face the outlet 2 from the peripheral wall, the fluid in the inlet 1 is sucked into the injection pipe by the steam blown in at high speed, and the fluid in the inlet 1 is blown into the injection pipe. The pressure is lowered, and the outlet port 2 increases the pressure inside the pipe by increasing the flow rate due to the mixing of steam. Due to the above phenomenon, the jet mixer outlet pressure becomes higher than the inlet pressure, so the mixed fluid flows from the bypass pipe outlet 8 to the bypass pipe inlet 7 and naturally maintains the balance between the jet mixer inlet pressure and outlet pressure. The fluid returned to the bypass pipe inlet merges with the feed fluid and is sucked into the jet mixer again through the feed port 1.

The decrease in the supply fluid, which is a cause of water hammer, can be prevented by being supplemented by the fluid returned to the bypass pipe inlet 7. If the steam decreases, the return through the bypass pipe 4 will also naturally decrease, and if it increases again, the return will also increase and balance will be maintained naturally. If the supply of feed fluid suddenly decreases and the amount of steam does not decrease rapidly in proportion to the amount of feed fluid, it is expected that balance will be lost and water hammer will occur on the outlet side of the jet mixer. If a bypass pipe is not installed, the rapidly increased volume will have no escape and will flow backwards in all directions due to the energy from the water hammer, so it is necessary to stop the steam and drain the two fluids that are the cause of the water hammer from the equipment. The only option is to let it escape or wait until the steam loses its heat and turns into hot water, reducing its volume. However, if a bypass pipe is installed, a balancing action will occur naturally, and the amount of water can be increased. Water hammer can be stopped simply by reducing the amount of steam.

Note that the bypass flow path according to the present invention may be arranged at any position other than the bench lily type flow path as long as it is the shortest distance connecting the points X1 at the supply fluid inlet position and X2 at the outlet position shown in FIG. It is valid.

〔Effect of the invention〕

As explained above, the present invention provides a bypass pipe between the feed fluid inlet and the feed outlet, in addition to the flow path of the main body, to cause fluctuations between the flow rate of the feed fluid and the mixed fluid. Also, by always maintaining a proper balance of pressure between the inlet and the outlet, it is possible to prevent the occurrence of water hammer, and at the same time, it is effective to ensure that the equipment and system function properly.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the structure of a jet mixer according to the present invention, FIG. 2 is a diagram showing the arrangement of bypass pipes according to the invention, and FIG. 3 is a conventional example of a jet mixer. DESCRIPTION OF SYMBOLS 1...Feeding fluid inlet, 2...Feeding fluid outlet, 3...Feeding pipe, 4...Bypass pipe, 5...Main body, 6...Injection pipe, 7...Bypass pipe inlet, 8 …
...Bypass pipe outlet, 9...Mixed fluid inlet, 10
... Injection passage, A... Main body flow path, B... Bypass flow path, C... Filler, a... Small hole.

Claims (1)

[Claims] 1. In a jet mixer that includes a built-in bench lily type flow path between an inlet for a feed fluid and an outlet for the feed fluid, and is provided with means for jetting and mixing a mixed fluid over a diverging flow path portion of the bench lily type flow path. , a bypass pipe connecting the inlet and the outlet in the shortest distance is provided separately from the bench-lily type flow path, and the bypass pipe has a cross-sectional area of the feed pipe of the feeding fluid. A jet mixer with a bypass mechanism, characterized in that the mixer has a cross-sectional area that exceeds the area obtained by subtracting the area of the smallest cross-sectional part of the mixer and is equal to the cross-sectional area of the feed pipe.