WO1990014152A1

WO1990014152A1 - Improved mixing nozzle apparatus and method of use

Info

Publication number: WO1990014152A1
Application number: PCT/US1990/002645
Authority: WO
Inventors: John Orava
Original assignee: John Orava
Priority date: 1989-05-15
Filing date: 1990-05-10
Publication date: 1990-11-29
Also published as: AU5631690A; CA2016722A1

Abstract

Generally there is provided a nozzle assembly (12) including an outer cylindrical casing member (32) and an inner cylindrical selection member (36). Inlets (14, 16, 18, 20, 21) are provided along the casing (32) and corresponding openings (50, 52, 54, 56, 57) are provided in the selection member (36) such that they may be selectively aligned with the casing inlets (14, 16, 18, 20, 21). The internal portion of the cylindrical selection member (36) functions as a film forming chamber where films (82, 86) are developed on the surface for mixing contact. Programmable pulsing pumps connected to the inlets (14, 16, 18, 20, 21) are sequentially operated to inject constituents into the mixing chamber in the desired order and quantity. Air pressure is periodically injected to clear the chamber of mixed constituents. With this programmable apparatus foam density and reaction time are variable during operation.

Description

IMPROVED MIXING NOZZLE APPARATUS AND METHOD OF USE

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates generally to mixing nozzle apparatus and methods of

use; and particularly to such nozzle apparatus for use with equipment in the

manufacture of foam. A typical application of such equipment being in the

insulation and packaging fields.

Description of the Prior Art

Chemical mixing for the foam machine industry has previously been accomplished by use of well known variable orifice valves used to control flow

rate in combination with mechanical mixing techniques. In such systems chemicals

under pressure are regulated either by a variable orifice or a selective orifice with

variable pumping velocities at the inlets. In that foam making equipment, the

ratio of the chemical constituents is accordingly controlled by selective adjustment

of the variable orifices or by control of the pumping rate. An example of such

prior mixing apparatus includes a mixing chamber into which the chemical constituents are sprayed under high pressure. Within the chamber the streams are

caused to impinge on obstructions to cause mixing, or in an alternative system a

mechanical device stirs the chemicals to cause the mixing. These devices result

in nozzle apparatus which is difficult to clean and within which reacted constituents collect to clog the nozzle. In addition to the high maintenance required, these devices generally require high pumping pressure to operate efficiently, and this pressure is dangerous and expensive to generate.

SUMMARY OF THE INVENTION

It is therefore a principal objective of the present invention to provide a

mixing apparatus which yields increased accuracy, increased control and improved mixing efficiency.

It is a further object to provide a mixing apparatus which is easy to clean and maintain, and to provide apparatus that is operable at a safe low pressure.

It is yet a further object of the present invention to provide a mixing

apparatus that is computer controllable, and which provides improved methods

of use with foam construction techniques.

Generally there is provided a nozzle assembly including an outer cylindrical

casing member and an inner cylindrical selection member. Inlets are provided along the casing and corresponding openings are provided in the selection member

such that the selection member openings may be selectively aligned with the casing

inlets. The internal portion of the cylindrical selection member functions as a film

forming chamber where films are developed on the inner surface for mixing

contact. Programmable pulsing pumps connected to the inlets are sequentially

operated to inject constituents into the mixing chamber in the desired order and

quantity. Air under pressure is periodically injected through a first inlet to clear

the chamber of the constituents. Methods of use include programming the pumping control to change the ratio of chemical constituents in response to encountered conditions. When used to

produce a foam product the programming would control the component ratios to

vary the density of the finished product or the time required for the chemicals to

react to create the foam. In use, the foaming reaction can be timed to occur only

after the chemicals are ejected and in the desired location. Moreover, the density may be varied over time or in response to mold conditions to give a desired

surface skin on a molded foam product.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a front view of the preferred embodiment of the present invention

showing the nozzle apparatus having a plurality of inlets for air and chemicals with

pulsing pumps connected thereto.

Figure 2 is a front view of the disassembled nozzle apparatus of Figure 1

showing the internal selection member.

Figure 3 depicts the movement of a chemical constituent pumped through an

inlet into the chamber. Figures 4a-4d represent a sequential operation of the nozzle apparatus

whereby first and second films are developed within the chamber and then

scrubbed out by an air jet.

While the invention will be described in connection with a preferred

embodiment, it will be understood that I do not intend to limit the invention to

that embodiment. On the contrary, I intend to cover all alternatives,

modifications, and equivalents as may be included within the spirit and scope of

the invention as defined by the appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning first to Figure 1, the nozzle apparatus 12 in accordance with the

present invention is shown having multiple inlets 14, 16, 18, 20 and 21 with

computer controlled pulsing pumps 22, 24, 26, 28 and 29 coupled thereto,

respectively. The computer (not shown) may comprise well known microprocessor technology which is programmable to provide timed pulses on data output ports.

These pulses may be amplified and used to drive the pumps. Air and chemical

constituents (see Figure 4a-4b) are injected into these inlets and the resultant

mixed product is ejected from the nozzle outlet 30.

The nozzle is formed of a hollow cylindrical casing member 32 having an

external thread attachment 34 at one end thereof. Its other extremity is generally

closed with the outlet 30 provided therethrough. In the preferred embodiment an

internal inlet selection member 36 is provided within the casing and is generally

of a hollow cylindrical design open at one extremity 38 to correspond to the nozzle

outlet. A threaded coupling 40 is arranged at its other extremity to mate with the

threaded end 34 of the casing to provide a tight seal thereto. The selection

member functions principally to seal the inlets when the inlet (or the entire

nozzle) is not in use. In the broad application of this nozzle, the basic function

is obtained with the casing alone, the inlets being controlled by the pumps.

Along the selection member there is provided patterns of inlet openings

arranged in series and circumferentially distributed around the selection member. In the location surrounding the selection member at the first inlet there is

provided a first series 50 of openings. In the preferred embodiment, air is provided to this inlet and this inlet may be selected in conjunction with other

combinations of inlets, or alone, by aligning the selection member to allow flow

from the selected inlets and closing off all others. Similarly, at the location on the

selection member corresponding to the second inlet, there is provided a second

series 52 of one or more openings. Third, fourth and fifth circumferentally

arranged series of openings 54, 56 and 57 are provided to control the third, fourth

and fifth inlets in the same manner. While the selection member is arranged to

rotatively provide selection, it is within the scope of the invention to arrange the

openings and the selection member to slideably provide the selection.

Operation of the nozzle apparatus of the present invention is illustrated in

Figure 3 and Figures 4a-4d. When a chemical constituent 60 is pumped through

an inlet 62 it passes through the opening 64 in the selection member 66 and

circulates within the cylindrical cavity 70. During the circulation a thin film is

caused to develop on the interior surface. Subsequent injection of a second

chemical constituent creates a second overlying thin film and thereby yielding a

high surface contact between the chemicals. Similarly, additional constituents may

be injected and layered in the chamber. Once the films have been developed, pressurized air is injected to scrub out the chemicals, cleaning the chamber,

ejecting the chemicals and causing further mixing of the constituents.

The operational process is depicted in Figures 4a-4d. Figure 4a shows the

chamber being scrubbed with air injected through the first opening 14. This air

stream is forced into the chamber by a selectively operated (programmable)

pulsing pump and the stream is caused to impinge on the chamber wall to set up

a turbulent flow which propagates down the tube to the exit orifice. In Figure 4b the first of the chemical constituents 80 is injected to the film forming chamber. The stream of chemical is selectively forced through the opening by a pulsing

pump. (The number of pulses and frequency is controlled by a programmable

computer.) The injected stream then circulates within the chamber to form a film

82 on the interior surface. Turning to Figure 4c the second chemical constituent

84 is similarly injected to form a second overlying film 86. Following the

development of the second film, additional films may likewise be developed by

injection through the remaining openings. When all required constituents have been injected, an air burst (Figure 4d) is again directed into opening 14 to expel

the films and to cause further intermixing. In this fashion, the interior of the

nozzle is kept free of reacting chemicals and difficult cleaning is avoided.

In the preferred embodiment the chemical constituents are pumped by computer controlled digital pumps. Pumps of this type are described in my co-

pending application, Serial No. 273,590. Under computer control, pump selection and pumping rate is selectively controllable, allowing an operator to program the

desired sequence and quantity of chemical constituents delivered.

Foam producing chemicals typically involve two or more components, the ratio

of which vary the density of the foam product and the time required for the

reaction that produces the foam product. Accordingly, the density and foaming

time can be controlled in a dynamic fashion, changing during operation under computer control in response to programming.

This programmability has been used in two major innovative methods.

Previously it has been the practice to inject a foam producing mixture into a cold

mold to produce a skinned foam product. In such system, the characteristics of the resulting product varies with the mold conditions and the mixture of chemical constituents. In accordance with the present invention, the controlling computer

is programmed to vary the chemical ratios during operation to affect the density.

Initially a mixture is used which generates a higher density foam. When this is

injected it covers the mold surface to form the skin. After a sufficient quantity

is injected the computer alters the ratio to produce a lower density foam for the

interior. This change is accomplished by varying the computer controlled pulse

signals to the pumps during the mold filling process.

Another appplication has been developed in the construction industry where

the foam is used as insulation. Wall cavities are typically filled by drilling holes spaced along the vertical dimension of the wall. Starting from the bottom, the

foam is injected through the holes, progressing from the bottom to the top. With the apparatus of the present invention only one top hole is drilled (and only one

hole needs to be patched) and the foam is injected into the cavity through this

hole. The computer is programmed to vary the signals to the pumps and

therefore the chemical ratios to control the time required for the foam to react

and set. This allows the mixture of chemicals time to flow to the bottom of the

cavity at the beginning; but during the injection process, the mixture is changed

to gradually shorten the setup time as the cavity is filled. From the foregoing description, it will be apparent that modifications can be made to the apparatus and method for using same without departing from the teachings of the present invention. Accordingly, the scope of the invention is only

to be limited as necessitated by the accompanying claims.

Claims

CLAIMSI claim:

1. A fluid mixing nozzle apparatus comprising: a cylindrical casing member having a plurality of inlets defined thereon, an

outlet defined on one end thereof, and a film forming chamber defined

therein; and

pump means for selectively providing bursts of fluid chemical constituents and

air under pressure into said inlets, such that said constituents form

juxtaposed thin film layers within said film forming chamber and said

air burst scrubs said juxtaposed layers of constituents from said film

forming chamber to produce bursts of mixed constituents.

2. The fluid mixing nozzle of Claim 1 wherein said pump means is controlled to

inject said chemical constituents sequentially into said film forming chamber

and to inject said air following said chemical injection to further mix and eject

said chemicals.

3. The fluid mixing nozzle of Claim 2 wherein said chemical constituents

comprise foam producing components and said pump means is programmable.

4. A method of mixing fluids comprising:

connecting a plurality of chemical constituents and an air supply to a plurality

of pulsing pump means; connecting each of said pulsing pump means to the inlets of a nozzle having

a plurality of inlets thereto, said nozzle having a film forming chamber therein and an outlet therefrom;

sequentially pumping bursts of said constituents into said film forming chamber

such that said constituents form juxtaposed thin film layers within said

film forming chamber; and

pumping bursts of air into said film forming chamber to scrub said juxtaposed

layers of constituents from said film forming chamber to produce bursts of mixed constituents.

5. The method of mixing fluids of Claim 4 wherein said chemical constituents

comprise foam producing components and said pump means is programmable.