JPS63116032A - Jet mixer with by-pass device - Google Patents

Abstract

PURPOSE:To prevent the generation of water hammer by installing a by-pass pipe which connects the inlet hole and outlet hole for feed fluid across the shortest distance and of which cross sectional area is set in such a range that the area is larger than the area formed by subtracting the minimum cross sectional area of a venturi type flow path from the cross sectional area of a feed pipe for feed fluid but not larger than the cross sectional area of the pipe. CONSTITUTION:The cross sectional area of a by-pass pipe 4 is specified in a value ranging from the cross sectional area with the same diameter as that of a feed pipe 3 to the area formed by deducting the area of a throat part which has the minimum cross sectional area in a venturi type flow path A from the cross sectional area of the feed pipe. When the outlet pressure of a jet mixer becomes higher than the inlet pressure, mixed fluid flows into the inlet hole 7 of the by-pass pipe from the outlet hole 8 of the by-pass pipe and the action keeping the balance between the inlet and outlet pressure of the jet mixer is naturally carried out and the fluid returning back to the inlet hole of the by-pass pipe joins feed fluid and is again sucked into the jet mixer. The reduction of the feed fluid is supplemented by the fluid returning back to the hole 7 and therefore, the generation of water hammer is able to be prevented.

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]

A jet mixer used in water heaters, heating equipment, reactor jackets, reflux heating of heat exchangers, showers, etc. that mixes two fluids using the mixing action of continuous fluid circulation. Alternatively, as a preventive device for the water hammer phenomenon that often occurs in systems equipped with the water hammer, a conventional means is to prevent the fluid chamber formed between the main body 5 and the injection chamber 6, as shown in FIG. An insert C such as a fibrous metal wire, a metal spring, or a small metal particle is inserted to prevent water hammer in the fluid chamber. In a typical jet mixer, a flow path A whose cross-sectional area is gradually reduced and then gradually enlarged is formed along the center line of an injection pipe inserted between an inlet port 1 and an outlet port 2 of a main body 5. The feeding fluid flows through the channel A at high speed, and the fluid (gas or liquid) to be mixed therewith is blown through the small hole a, and the mixed fluid is thoroughly mixed and sent out from the outlet 2.

[Problem that the invention seeks to solve]

However, if the supplied fluid is decreased, it becomes impossible to flow through the flow path A at a high speed. The feed fluid, which is no longer able to flow at a high speed, and the fluid blown from the small hole a are not mixed well and are sent out from the delivery port 2.

When the fluid to be mixed is steam, the volume of steam is reduced to the volume of liquid when mixed, but two fluids (steam and liquid) sent out without being mixed well are When it is sent to the connected pipe, the pressure inside the pipe increases rapidly because there is not enough space to receive the increased volume due to the peripheral wall of the pipe, and this rapidly increased volume has no place to escape, and the inlet The water may suddenly flow back into the air inlet and cause water hammer.

If this water hammer cannot be stopped urgently, it will cause damage to the equipment itself and equipment, and - even if the damage is temporarily avoided, the steam that is the cause of the water hammer will be stopped. Water hammer cannot be stopped unless you do so. Stopping the steam means stopping the operation, at least temporarily, and cannot avoid damage caused by repeated occurrences of water hammer.

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

[Means for solving problems]

The present invention aims to eliminate the above-mentioned drawbacks to the jet mixer main body and device, and to provide a device designed to eliminate pressure loss in the Venturi-type flow path within the main body, In the jet mixer, the jet mixer has a built-in venturi-type flow path between the outlet of the feeding fluid and a jet mixer for jetting and mixing a mixed fluid over a diverging flow path portion of the venturi-type flow path, the venturi-type flow path being Separately, connect the inlet port and the outlet port at the shortest distance.
A bypass pipe is provided, and the bypass pipe has an area larger than the area obtained by subtracting the area of the smallest cross-sectional part of the Venturi-type flow path from the cross-sectional area of the feed pipe for the feed fluid and up to the same cross-sectional area as the feed pipe. constitutes a jet mixer with a bypass mechanism characterized by having a cross-sectional area in the range of
In addition to preventing the occurrence of water hammer, this has a great effect on simplifying equipment design and improving the economic efficiency of equipment.

〔Example〕

The present invention will be described 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 is aligned on the main body longitudinal axis,
An injection pipe 6 is built-in to form a venturi-type flow path A consisting of a convergent flow path portion, a throat portion, and a diverging flow path portion between an inlet port 1 and an outlet port 2 connected to a feed pipe 3 for the feed fluid. The fluid chamber formed between the main body 5 and the injection pipe 6 is filled with a fibrous insert C. Reference numeral 9 denotes an inlet for mixed fluid, and 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 supplied fluid.

The characteristic structure of this invention is that a bypass pipe 4 is disposed between the inlet 1 and the outlet 2, which has a bypass flow path B that connects the two in the shortest distance, in addition to the venturi type flow path. In addition, the cross-sectional area of the bypass pipe 4 is 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 venturi-type flow path A from the cross-sectional area. Specified for values in the range between . Note that the bypass pipe inlet is indicated by 7, and the bypass pipe outlet is indicated by 8.

[For production]

Initially, the feed fluid naturally separates into the inlet 1 and the bypass pre-lower, and then joins again at the outlet 2 and the bypass pipe outlet 8.

By installing this bypass pipe, conventionally when the feed fluid flows only through the flow path A whose cross-sectional area is gradually reduced and then gradually expanded, it becomes a resistance and is accompanied by a pressure loss. The feed fluid flows through the jet mixer without experiencing any pressure loss because the jet mixer separates into a bypass pipe with a very small amount of water.

Next, when steam (mixed fluid) is sent from the inlet 9 and mixed with the fluid that has flowed into the flow path A of the feed fluid, the steam enters the feed fluid from the small hole a of the injection passage 10 of the injection pipe 6. Since the small hole a faces the outlet port 2 from the peripheral wall, the fluid in the inlet port 1 is sucked into the injection pipe by the steam blown in at high speed, reducing the pressure in the inlet port l, and the outlet port 2 The jet mixer outlet pressure becomes higher than the population pressure due to the above phenomenon that increases the pressure inside the pipe due to the increase in flow rate due to mixing of steam, so the mixed fluid flows from the bypass pipe outlet 8 to the bypass pre-man lower and the inlet pressure of the jet mixer increases. The fluid that returns to the bypass pipe inlet joins the feed fluid and is sucked into the jet mixer again from the feed port 1.

To reduce the amount of fluid supplied due to water hammer,
Bypassing can be prevented by replenishing the fluid that returns to the preman lower. 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 place to escape and the energy from the water hammer will cause it to flow backwards in all directions. Therefore, it is necessary to stop the steam and allow the two fluids that cause the water hammer to escape from the equipment. The only option is to wait until the steam loses heat and becomes hot water, reducing its volume. However, if a bypass pipe is installed, a balance will be maintained naturally, and the amount of water will be increased or the amount of steam will be reduced. Water hammer can be stopped simply by reducing .

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

〔Effect of the invention〕

As explained above, in this invention, apart from the flow path of the main body,
By providing a bypass pipe between the supply fluid inlet and outlet, the pressure between the supply port and outlet can always be kept in an appropriate balance even if there are fluctuations between the flow rate of the supply fluid and the mixed fluid. This has the effect of preventing possible occurrence of water hammer and also allowing the equipment and system to 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 present invention, and FIG. 3 is a conventional example of a jet mixer. ■...Feeding fluid inlet 2...Feeding fluid outlet 3...Feeding pipe 4...Bypass pipe 5...Main body 6...Injection pipe 7...Bypass pipe population 8 ... Bypass pipe outlet 9 ... Mixed fluid inlet lO ... Injection passage A ... Main body flow path B ... Bypass flow path C ... Filler insert a ... Small hole

Claims (1)

[Claims] In the jet mixer, the jet mixer has a built-in bench lily type flow path between a feeding fluid inlet and a feeding fluid outlet, and is provided with a jet mixing means for mixing fluid over a diverging flow path portion of the bench lily type flow path. Apart from the bench lily type flow path,
A bypass pipe is provided that connects the inlet and the outlet in the shortest distance, and the bypass pipe has an area obtained by subtracting the area of the smallest cross-sectional portion of the bench lily-shaped flow path from the cross-sectional area of the feed pipe of the feed fluid. 1. A jet mixer with a bypass mechanism, characterized in that the jet mixer has a cross-sectional area in a range that exceeds the above-described cross-sectional area and is the same cross-sectional area as the feed pipe.