WO1988003052A1

WO1988003052A1 - Liquid mixing and extruding or spraying method and apparatus

Info

Publication number: WO1988003052A1
Application number: PCT/JP1987/000788
Authority: WO
Inventors: Masafumi Matsunaga
Original assignee: Nordson Corporation
Priority date: 1986-10-21
Filing date: 1987-10-16
Publication date: 1988-05-05
Also published as: JP2513475B2; AU8100187A; JPS63104679A; KR880701586A

Abstract

A liquid mixing and extruding or spraying method and apparatus, in which two types or liquids (C, D) to be mixed are supplied to narrow paths (13-14) whose outlet ports are opposed to each other. The liquid flows through the opposed outlet ports collide each other in a mixing chamber and are mixed therein. Such mixing cycle is repeated as desired, through similar structures, and then the mixture of the liquids is extruded or sprayed through a nozzle.

Description

DESCRIPTION

TITLE OF THE INVENTION

Liquid Mixing and Extruding or Spraying Method and Apparatus

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to liquid mixing and extruding or spraying method and apparatus. Description of the Related Art

In liquid extrusion and application operations or liquid spraying and application operations, it is rare to use a liquid singly. Different types of liquids are often mixed and used-. Mixing of these liquids is often performed before they are poured in an extruding or spraying applicator. If these liquids are mixed in the applicator, it is difficult to maintain a very precise mixing ratio and obtain uniform dispersion. If a specific mixing apparatus and the corresponding operations are not performed, a satisfactory solution mixture cannot be prepared.

In recent years, however, liquids must be mixed immediately before extrusion or spraying in many occa¬ sions. For example, such an occasion is handling of a two-part curing resin. In these occasions, a mixer is directly coupled to a gun. Conventional guns for such an application are as follows: Gun with Static Mixer

A typical structure of a gun with a static mixture is shown in Fig. 10. An extruding gun 167 is connected to one end of a baffle plate type mixer 161. Two types of compressed liquids R and Q are' supplied from the corresponding inlet ports and are flowed in a downstream portion and are mixed by baffle plates 162A, 162B, .... However, a good mixing effect cannot b^*e obtained, and the above operation must be repeated several times. As the number of mixing cycles is increased, a better mixing, effect can be obtained. For this reason, the length of the mixer falls within the range of 300 mm to 1,000 mm. This length corresponds to the length of a mixing chamber and such a large length causes Various problems. First, the liquid in the mixing chamber is not completely mixed, and a large amount of incomplete mixture results in waste of liquids. Second, since the flow path is long, the liquids may react wi_.th each other, and the resultant mixture cannot then be extruded. Third, cleaning of the mixture is cumbersome. Fourth, this mixture is not heated in order to prevent chemical reactions of the liquids and is therefore unsuitable for a paint having a high viscosity and for use during the winter time.. Gun with Rotary Stirrer Type Mixer

A typical structure of a gun with a rotary stirrer type mixer is shown in Fig. 11. An extruding gun 177 is connected to one end of a lateral stirrer type mixer 171. The volume of the stirring tank is at least 500 cc. In this case, the liquids are wasted in the same manner as described above. A seal 175 of a high-speed rotation shaft of each stirring fin is easily damaged, and its maintenance is cumbersome.

It is difficult to improve the above conventional guns due to their structural features. The present inventor made extensive studies from a viewpoint entirely different from the conventional ones.

The present invention is made for simplifying a mixing process, shortening a mixing time, and decreas¬ ing the size of the apparatus. SUMMARY OF THE INVENTION It is an object of the present invention to provide liquid mixing and extruding or spraying method and apparatus, wherein two types of liquids to be mixed are supplied from corresponding smaller flow paths, i.e., narrow paths, outlets of the narrow paths oppose each other, liquid flows from the narrow paths collide head- on with each other, thereby mixing the two types of liquids and hence extruding or spraying a liquid mixture. BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a sectional view for explaining a basic method according to the present invention;

Fig. 2 is a sectional view showing a development of the ±>asic method of the present invention; Fig. 3 is a view for explaining head-on collision;

Fig. 4 is a view for explaining oblique collision; Fig. 5 is a sectional view of a basic structure according to an embodiment of the present invention; Fig. 6 is a sectional view showing a development of the basic structure shown in Fig. 5 according to another embodiment of the present invention?

Fig. 7 is a sectional view of the structure shown in Fig. 6 taken along the line "E" - "F" thereof; Fig. 8 is a plan view of a structure wherein slit holes of stacked baffle mixing plates cross each other _f

Fig_* 9 is a plan view of a structure wherein slit holes of stacked baffle mixing plates are parallel to each other;

Fig. 10 is a conventional static type mixing/ extruding apparatus; and

Fig. 11 is a conventional stirring type mixing/ extruding^* apparatus. DETAILED_DESCRIPTION OF THE PREFERRED-EMBODIMENTS Basic Method

Referring to Fig. 1, two types of compressed liquids A and B are supplied to flow paths 1 and 2, and the flow paths 1 and 2 are restricted to constitute narrow paths 3 and 4, respectively. Outlet ports of the narrow paths 3 and 4 oppose each other, and liquid flows Al and Bl having an increased flow speed collide head-on with each other, thereby mixing these liquids to obtain a solution mixture ABl. The solution mixture ABl is supplied to one flow path 6 extending, preferably, in a direction perpendicular to the liquid flows Al and Bl. The solution mixture ABl is guided through an extruding path 6 in a gun 10 and is extruded or sprayed from a nozzle 7.

The head-on collision is defined as a collision wherein the liquid flows from the narrow paths oppose each other and are aligned on a straight line, as shown in Fig. 3. A collision force in this case is greater than the force generated in the conventional static or stirring type gun. When a flow speed of each of the liquid flows Al and Bl is 30 m/sec or more, the effect can be maximized. By such a large collision force, these liquids are disturbed and dispersed as particles, i.e., mixing is performed. Many unknown factors involve in a hydrodynamic calculation, and the calculation is difficult and will be omitted. The force generated by the collision, i.e., the amounts and speeds of liquid flows from the narrow paths depend on a compression force acting on the liquid, a shape of the narrow path, the cross-sectional area of the narrow path, the length of the narrow path, liquid properties, and a temperature during flowing. Therefore, in order to change a mixing ratio of these liquids, the above factors must be changed. i In the head-on collision, if a great difference between the forces generated by the liquid flows from the narrow paths is present, a large force acts on the outlet port for the liquid flow having a small force, and its flow is undesirably inhibited. In order to prevent this, directions of the liquid flows should not be aligned on a single straight line. In other words, these directions are set to form an angle therebetween, and oblique collision can be performed. Therefore, the large force does not directly act on the outlet portion for the liquid flow having a small force. The oblique collision is illustrated in Fig. 4. The directions of the two liquid flows cross' each other. As compared with head-on collision, a force generated by the collision is relatively small, and degradation of the mixing effect cannot be inevitably prevented.

Development of Basic Method

The development of the basic method provides a method in which, the basic operation is repeated several times and the liquids are mixed in a multi-stage structure.

Referring to Fig. 2, two types of compressed liquids C and D are supplied to flow paths II and 12, and the flow paths are. made smaller to constitute narrow paths 13 and 14, thereby increasing flow speeds of the. liquids flowing through the narrow paths 13 and 14. At the same time, the outlet ports of the narrow paths oppose each other to cause liquid flows Cl and Dl to collide head-on with each other. The liquids Cl and Dl are mixed to obtain a first liquid mixture CDl. The first liquid mixture CD1 is guided to one flow path 16 extending in a direction perpendicular to the liquid flows Cl and Dl. The first liquid mixture CDl is divided into two flows 17 and 18 which are then respectively supplied to narrow paths 23 and 24, thereby further increasing the flow speeds of the liquid flows. The outlet ports of the narrow paths 23 and 24 oppose each other to cause liquid flows CDla and CDlb to collide head-on with each other to obtain a second liquid mixture CD2. The second liquid mixture CD2 is guided to one flow path 25 extending in a direction perpendicular to the liquid flows CDla and CDlb. The above operation is repeated to obtain a third liquid mixture CD3, a fourth liquid mixture CD4, ..., and the last liquid mixture is guided to a nozzle 47 or the like through one flow path 46, thereby extrud¬ ing or spraying it.

If the speeds of the liquid flows in the above-mentioned head-on collision are low, a desired mixing effect cannot be obtained. According to a test, one of the liquid flows preferably had a speed of at least 30 m/min.

. Liquids having good effects in the test are a 052 s ' ' **-

- 8 -

melting type coating material, an emulsion type coating material, and a major constituent, a curing agent, a catalyst, or a solvent in a two-part curing resin.

Of these liquids, let alone a liquid having a relatively high viscosity, the viscosity of a liquid may be decreased to increase the flow rates of the liquid flows from the narrow paths during precision control of the mixing ratio. For this purpose, the liquid may be heated. A first embodiment of the present invention will be described with reference to Fig. 5.

Two automatic opening/closing valves 51A and 51B for supplying liquids are mounted on a- body 60 of an apparatus. Outlet flow paths 58A and 58B of the valves 51A and 5IB respectively communicate with two inlet flow paths 59A and 59B formed in the body 60. The inlet flow paths 59A and 59B are respectively connected to two upstream flow paths 64A and 64B on a mixing plate 61 disposed in a gun body. Tk® mixing plate 61 has a cylindrical shape and is divided into upper and lower halves. The upper half serves as a slit plate 62. The upstream flow paths 64A and 64B extend through the upper surface of the slit plate 62 and are symmetrical about the central point of the slit plate 62. A blind hole 67s having a depth Dl and serving as part of a mixing chamber is ormed. at the central portion of the lower half of the plate 62. Two slits 65 and 66 are formed on a line connecting the blind hole, the upstream flow path 64A and the upstream flow path 64B. The lower half serves, as a mixing plate 63. A mixing chamber 67 having a depth D2 and the same diameter as that of the blind hole 67s is formed at the center of the mixing plate 63. A downstream flow path 68 is formed below the chamber 67.

The downstream flow path 68 of the mixing plate 61 is connected to an extruding flow path 69 in the body 60 and to a nozzle 70.

The operation of the first embodiment will be described with reference to Fig. 5.

The two types of liquids A and B compressed at predetermined pressures are supplied through the inlet flow paths 59A and 59B in the body 60 through the automatic valves 51A and 5IB and reach the. mixing plate 61. These liquids pass through the upstream flow paths 64A and 64B on the upper surface of the upper half (i.e., the slit plate 62) of the plate 61 and reach narrow paths or slits 65 and 66, respectively. When these liquids pass through the slits 65 and 66, their flow speeds are increased to about 30 m/sec. The flows of the liquids A and B from the slits 65 and 66 serve as the liquid flows Al and Bl, and the flows Al and Bl collide head-on with ea.ch other. In this case, the liquids A and B are reduced to fine particles since their speeds are high and their moments are large. A turbulence caused by the collision allows mixing of the liquids A and B. The liquid mixture ABl is flowed out from the mixing chamber 67 to the downstream flow path, 68. The mixture passes through the extruding flow path 69 in the body 60 and is extruded or sprayed from the nozzle 70 or the like connected thereto.

A structure of a second embodiment of the present invention will be described with reference to Figs. 6 and 7.

Two automatic opening/closing valves 91A and 9IB for supplying the liquids are mounted on a body 100 of an apparatus, outlet flow paths 98A and 98B of these valves respectively communicate with inlet flow paths 99A and 99B formed in the body 100. The inlet flow paths 99A and 99B respectively communicate with upstream flow paths 104A and 104B formed on a first mixing plate 101 disposed in the body 100. The first mixing plate^" 101 has a cylindrical structure. The two upstream flow paths 104A and 104B are formed in the peripheral portion of the upper surface of the mixing plate 101 and are symmetrical about the center of the plate 101. A blind hole having a depth D3 is formed in a part 107s of the mixing chamber. Two slits 105 and 106 are formed on a line.connecting the blind hole, the upstream flow path 10 A and the upstream flow path 104B.

A second mixing plate 111 is formed on the lower surface of the first mixing plate 101. The second mixing plate 111 has a cylindrical structure as in the first mixing plate 101. The structure having the branch flow paths of the downstream flow path from the mixing chamber is placed or stacked on the second mixing plate 111. A hole having the same diameter as that of the part (blind hole) 107s of the mixing chamber at the lower surface of the first mixing plate 101 is formed on the upper surface of the second mixing plate 111 and has a depth D4, and the resultant structure serves as a mixing chamber 107. One downstream- flow path 108 having a depth D5 is formed below the mixing chamber 107. Branch flow paths 113A and 113B aligned on a straight line are formed to extend by a predetermined length L perpendicularly with respect to the downstream flow path 108. Upstream flow paths 114A and 114B are formed on the lower surface of the second mixing plate HI and extend downward from the upstream flow paths 113A and 113B at a right angle. Other arrangements are the same as those in the first mixing plate 101. More specifically, a blind hole is formed as a part 117s of the mixing chamber at the central portion of the lower surface of the second mixing plate 111. Two narrow paths or slits 115 and 116 are formed on central, lines connecting the blind hole and the upstream flow path 114A and connecting the blind hole and the upstream flow path 114B, respectively. When assembling, the second mixing plate 111 and the first mixing plate 101 are so stacked that, the slits 105 and 106 and the slits 115 and 116 cross each other. In the above structure, two mixing plates are stacked. However, a third mixing plate 121 having the same arrangement as that of the first or second mixing plate may be stacked on the above structure. In addition, a plurality of plates including a fourth mixing plate 131, a fifth mixing plate 141, ... may be stacked, and the resultant structure may be built into the body 100.

A downstream flow path 148 from a mixing chamber 147 of the last mixing plate communicates with an extruding flow path 149 in the body 100 and is connected to a nozzle 150 or the like.

The directions of the narrow paths or slits of the stacked plates are perpendicular to each other when viewed from the top (Fig. 8) . However, they may be aligned on a line when viewed from the top (Fig. 9).

A preferable sectional shape of the slit is a rectangular or square shap'e in cross section. The rectangular slit can be easily manufactured, and the square slit has a low flow resistance.

The operation of the structure of the second embodiment will be described with reference to Figs. 6 and 7. The two types of liquids C and D compressed at predetermined pressures are supplied through inlet flow paths 99A and 99B in the body 100 through the automatic opening/closing valves 91A and 9IB and reaches the first mixing plate 101. The liquids are supplied to the upstream flow paths 104A and 104B and then the narrow paths or slits 105 and 106. While the liquids pass through the slits, the flow speeds of the liquids C and D are increased and are flowed in the mixing chamber 107 through the opposite slits. In this case, these liquids have a high speed and a large momentum and are reduced to fine particles to generate a turbulence, thereby mixing the liquids C and D. A 'liquid mixture CDl is flowed out from the mixing chamber 107 and is supplied to the downstream flow path 108. The liquid mixture CDl passes through the branched flow paths 113A and 113B, and the branched flows are respectively supplied to the upstream flow paths 114A and 114B and the narrow paths or slits 115 and 116. In the same manner as described above, the liquids are flowed out through the corresponding slits and a head-on collision allows second mixing of the liquids. Therefore, the liquid mixture CD2 is obtained by the first and second mixing plates 101 and 111. However, additional mixing cycles are often required. In this case, the liquids pass through the third mixing plate 121 and then the fourth and fifth mixing plates 131 and 141, all of which have the same structure as that of the second mixing plate 111, thereby obtaining the same effect as described above. A liquid mixture CDx prepared in a satisfactory condition is supplied to the extruding flow path 149 in the body 100 and is extruded or sprayed from the nozzle 150 into air.

According to the method and apparatus of the present invention, two types of liquids can^* be mixed in a mixing chamber having a small volume of 0.5 to 2.0 cc so as to perform most effective mixing. If needed, the mixing cycle is repeated, and a very precise mixing ratio can be set. In addition, movable parts are eliminated rom the apparatus, and the apparatus has a simple structure. Furthermore, maintenance can be simplified, and heat loss is also small. A high- temperature liquid can be extruded or sprayed, thereby contributing to improvement of product quality and working efficiency.

Claims

1. A method of mixing extruding, and spraying liquids, comprising: supplying two types of liquids (A, B) through the respective flow paths (1, 2), restricting the flows through the respective narrow paths (3, 4) to increase flow speeds; making the restricted flows collide with each other through the opposed outlet ports of the narrow paths, thereby obtaining a liquid mixture (ABl); and extruding or spraying the liquid mixture from an extruding means (7) through one flow path (6).

2. A method of mixing, extruding, and spraying liquids, comprising: supplying two types of liquids (C, D) through the respective flow paths (11, 12), restricting the flows through the respective narrow paths (13, 14) to increase flow speeds; making the restricted flows collide with each other through the opposed outlet ports of the narrow paths, thereby obtaining a liquid mixture (CDl); guiding the liquid mixture (CDl) to one flow path (16); supplying the liquid mixture (CDl) into two flow paths (17, 18) and restricting the last mentioned flow paths (17, 18) to constitute a second narrow paths (23, 24), thereby increasing flow speeds; making the second restricted flow collide with each other to obtain a second liquid mixture (CD2); guiding the second liquid mixture (CD2) to another flow path (25); repeating the above cycle; and extruding or spraying a last liquid mixture (CDx) from another extruding means (47) through still another flow path (46).

3. A method according to claim 1 or 2, wherein the flow speed of at least one of the liquids at the time of the collision is 30 m/sec or more.,

4. A method according to claim 1 or 2, wherein each liquid is a material selected from the group consisting of a melting type coating material, an emulsion type coating material, and a major consti- tuent, a curing agent, a catalyst, and a solvent of a two-part curing resin.

5. A method according to claim 1 or 2, wherein at least one of the liquids is a liquid heated to a temperature higher than room temperature.

6. An apparatus for extruding or spraying liquids, comprising: liquid mixing means (61) comprising two liquid supply valve means (51A, 5IB) and two inlet flow paths (64A, 64B) respectively communicating with said two valve means, said liquid mixing means (61) including upper and lower disk-like members, said upper disk-like member being arranged such that through holes constituting said two inlet flow paths (64A, 64B) are formed in a peripheral portion of said upper disk-like member and are symmetrical about a central point thereof, a blind hole (67s) is formed on a lower surface of said upper disk-like member, and opposite flow paths (65, 66) with respect to the center are formed between said blind hole (67s) and said two inlet flow paths (64A, 64B), and said lower disk-like member (63) having a hole of the same diameter as that of said blind hole (67) and cooperating with said blind hole to constitute a mixing chamber; and a downstream flow path (68) continuous with said mixing chamber; and extruding means including an extruding flow path (69) connected to said downstream flow path (68) and having a predetermined length, and an extrud¬ ing opening connected to said extruding path (69).

7. An apparatus for extruding or spraying liquids, including two liquid supply valve means (91A, 9IB), and a liquid mixing unit (101) having two inlet flow paths respectively communicating with said valve means , said liquid mixing unit being provided with a cylindrical first liquid mixing plate (101), said first liquid mixing plate (101) being arranged such 3052

- 18 -

that through holes constituting said two inlet flow paths are formed in a peripheral portion of said first liquid mixing plate and are symmetrical about the center thereof, a blind hole is formed at a central portion of a lower surface of said first liquid mixing plate, arid opposite flow paths (105, 106) are formed between said blind hole and said two inlet flow paths, said liquid mixing unit being further provided with a cylindrical second liquid mixing plate (111), said second liquid mixing plate (111) being arranged such that a central hole (107) communicating with said blind hole of said first liquid mixing plate is formed in said second liquid mixing plate and cooperates with said blind hole to constitute a first liquid mixing chamber, said first mixing chamber being adapted to communicate with one downstream flow path (108) extend¬ ing downward in a direction of a central line of said cylindrical second liquid mixing plate (111), said one downstream flow path being branched midway therealong into branch flow paths (113A, 113B), said branch flow paths terminating into other downstream flow paths (114A, 114B) at lower ends thereof, said second liquid mixing plate being arranged such that a blind hole (117s) is formed at a central portion of a lower surface thereof, and other opposite flow paths (115, 116) are formed between said blind hole (117s) and said other downstream flow paths (114A, 114B) , said liquid mixing unit being provided with an additional one or a plurality of additional liquid mixing plates each having the same structure as that of said second liquid mixing plate to constitute an additional one or a plurality of additional liquid mixing chambers, and a last liquid mixing chamber (147) of said plurality of additional liquid mixing chambers being connected to liquid extruding means (50) having a liquid extruding opening.

8. An apparatus according to claim 7, wherein said opposite flow paths and said other opposite flow paths adjacent thereto are offset by a predetermined angle.