JPS6158214B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION It is common practice to mix particulate solids, liquids, and gases in motionless mixers. As the name suggests, non-moving mixers contain no moving parts. Mixers of this type consist of baffles of various types arranged in a sequential manner in tubes or pipes. Due to the splitting process and the combining process, the separately injected components are mixed or dispersed into each other at the outlet end of the tube or pipe.

However, difficulties often arise when mixing materials of widely different viscosities and/or of vastly different flow rates. For example, in the field of polymers, it is desirable to mix very small amounts of low viscosity materials into much larger amounts of high viscosity materials. When this is done, the low viscosity substances tend to pass through the mixed material without mixing with the high viscosity substances to any significant extent.
For example, if you want to mix a flow of a polymer with a viscosity of 30 million centipoise at a flow rate of 7 g/min with a second flow of a material with a viscosity of 6 centipoise at a flow rate of 0.035 g/min. It is.

Various methods have been attempted to initially disperse or mix low viscosity materials at the point of injection.
Examples of these methods include the use of multiple injection holes located around the periphery of the tube. A second method is the use of a relatively small diameter pipe for carrying low viscosity substances, passing through the diameter of the main pipe carrying high viscosity substances. The small diameter pipe is shaped with multiple holes that are used to inject low viscosity fluids. A common problem with such devices with parallel passage outlets is that the low viscosity fluid injection openings become clogged to varying degrees, resulting in asymmetric distribution.

It is known that one of the mechanisms that allows mixing of fluids is diffusion. However, when dealing with typical highly viscous substances that produce laminar flow, the diffusivity is very small. It is known that the mass transfer rate N of a diffusive component, measured in moles per unit area per second, is equal to the product of the diffusion coefficient D and the local concentration gradient dc/dr.

That is, N∝Ddc/dr Since D is small in a highly viscous substance, it is necessary to increase the local concentration gradient dc/dr in order to maximize the mass transfer rate N.

It is therefore an object of the invention to provide a motionless mixing device which does not have the disadvantages of the corresponding devices according to the prior art.

Another object of the present invention is to provide a motionless mixing device that is particularly useful for mixing two or more fluids having significantly different viscosities.

Yet another object of the invention is to provide a motionless mixing device that maximizes the mass transfer rate N to improve diffusion between the fluids to be mixed.

These and other objects of the invention will be more fully understood upon consideration of the following disclosure and accompanying drawings.

Referring again to the above scheme, the mass transfer rate N is
Increased by decreasing dr. In principle, this could be achieved by placing a relatively small diameter pipe across a larger pipe or tube diameter. In that case, the small diameter pipe shall have a thin hole with a narrow width in its longitudinal direction. Although the fluid components exiting the slots may be introduced in very thin sheets, the above-mentioned hole clogging problem still persists with this method.

These problems are solved by providing a device that includes an elongated hollow tubular member as described below. The reduced diameter portion of the elongate hollow tubular member includes (a) at least two orifices, preferably generally cylindrical, having axes substantially parallel to the axis of the tubular member for carrying a first fluid; ) Forming a mixing region including a fluid inflow hole for discharging the second fluid approximately in the middle of the two orifices on or in the vicinity of a tangent to the orifices.

Referring to FIG. 1, a mixing device 10 includes a hollow tubular member 1 having a tapering diameter at 9, which includes, for example, two orifices 5, 6 for passing relatively highly viscous fluids. has. Although the cross section of the orifice is shown as circular, it does not necessarily have to be circular.

The low viscosity fluid inflow hole 15 is preferably a hollow tube 20
including an orifice located within. The tube 20 is shown extending radially through the side wall of the elongated hollow tubular member 1. The low viscosity fluid is allowed to enter the motionless mixer of the present invention through a hollow tube and its discharge rate is controlled by a pump device (not shown).

As shown in FIGS. 1 and 2, the hollow tube 20 passes through the hollow member 1 in the radial direction so as to pass through the center point of each orifice 5,6. This was done to obtain symmetry. However, while still achieving the advantageous mixing properties desired here, it may also be suitable for the hollow tube 20 to penetrate the side wall of the hollow tubular member 1 at other positions, for example offset by 90° from the position shown. be.

Without the orifices 5 and 6, the low viscosity fluid entering the high viscosity fluid stream from the inflow hole 15 simply forms a thin linear flow when the fluid passes through the hollow tubular member 1. However, by practicing the present invention, it has surprisingly been found that the low viscosity fluid forms an elongated flat surface across the pipe diameter, greatly increasing molecular diffusion between the low viscosity and high viscosity fluids. did. This typically increases the surface area available for diffusion by a factor of 25 to 50, while simultaneously increasing the value of dc/dr.

As previously mentioned, the present invention is particularly advantageous for mixing fluids with significantly contrasting viscosities. Ideally, the viscosity ratio of the first and second fluids should be approximately
Should be 1000:1 or higher.

The reduced diameter section 9 forming the mixing region in which two or more orifices are formed can take a number of shapes. It has been found that when the sidewalls of the reduced diameter section 9 are radially perpendicular to the circumference of the hollow tubular member 1, some fluid can settle in the stagnation area near the inner sidewall of the hollow tubular member. There is. Therefore, it is preferable to make the side wall of the reduced diameter portion 9 slope,
The inclination is most typically 45° to the centerline of the hollow tubular member 1.

FIG. 3 shows yet another embodiment of the present invention, in which instead of providing a single hole 15 as a low viscosity fluid discharge hole as shown in FIGS. The discharge hole shown in FIG. 3 includes an orifice formed at the end of a hollow tube 3 and a solid rod 4. As in the previous embodiments, the side walls of the elongated hollow tubular member 1 are radially penetrated by hollow tubes and solid tubes. A low viscosity fluid enters the motionless mixer of the present invention from a hollow tube, the discharge rate of which is directly correlated to the end spacing of the hollow tube and the non-hollow space.

The advantages realized by using the embodiment shown in FIG. 3 over those shown in FIGS. 1 and 2 are that the discharge rate of the low viscosity fluid can be easily controlled; The advantage is that the viscous discharge holes can be more easily prevented from clogging. Thus, although some cleaning of the open end of the tube may be achieved by bringing the tube 3 and rod 4 into contact, even greater cleaning may be achieved by actually removing the hollow tube from the hollow tube member 1.

The invention is particularly advantageous when used upstream of a conventional secondary mixing device. Mixing high density and low density fluids is difficult for the aforementioned reasons, especially when conventional equipment is employed.

By placing the biviscous fluid mixer of the invention upstream of various static mixers that have no mechanical automatic parts and incorporate stationary obstacles, these latter devices have a partially pre-mixed A fluid flow containing a high viscosity matrix flow with a thin plate-like low viscosity fluid of . Creating a partially premixed low viscosity fluid is a condition that greatly increases final mixing.

The converging parts 5, 6 need not have a circular cross section as shown in the accompanying drawings. In fact, almost any shape with a substantially curved circumference can be used. Naturally, there are countless possibilities, and it is not possible to list all individual examples. Therefore, while the embodiments of the invention as shown and described may fully accomplish the stated objectives and desired advantages, such embodiments are intended to be illustrative and not limiting. I hope you understand that.

[Brief explanation of the drawing]

FIG. 1 is a full-scale drawing of an embodiment of the present invention, FIG. 2 is a plan view of the device shown in FIG. 1, and FIG. 3 is a diagram showing a modification of the feed hole for low viscosity fluid. . 10... Mixing device, 1... Hollow tubular member, 5, 6...
Orifice, 15... Viscous fluid inflow hole, 9... Diameter reduction part, 20... Hollow tube.

Claims (1)

[Scope of Claims] 1. A mixing device for two or more fluids having a mixing region in a reduced intermediate portion of an elongated hollow tubular member, A. at least two orifices having generally parallel axes and tapering with respect to the sidewalls of the hollow tubular member; A mixing device comprising a radially extending solid rod and an inlet hole formed at an end of a hollow tube, wherein the first fluid and the second fluid have a viscosity ratio of at least about 1000:1. 2. A mixing device for two or more fluids having a mixing region in a reduced intermediate portion of an elongated hollow tubular member, A. having an axis substantially parallel to the axis of the hollow tubular member for transporting a first fluid; B. at least two orifices tapering with respect to the sidewalls of the hollow tubular member; an inlet hole defined in a hollow tube extending radially through a side wall, wherein the first fluid and second fluid have a viscosity ratio of at least about 1000:1.