Liquid dispensing spray nozzle assembly for rapidly producing small droplets of highly viscous liquids.

Abstract

The modular liquid distribution system (10) comprises a module body, a spray nozzle (30), and a repeatable piston for controlling the discharge of a high-viscosity liquid from the spray nozzle (30). Each spray nozzle (30) has a nozzle body with a liquid inlet and a teardrop-shaped pintle (83), the pintle together with the nozzle body defining an expansion chamber that sufficiently reduces the velocity of the liquid so that it is discharged in the form of small droplets without splashing.

Description

Technical Field

[0001] Cross - reference to related applications

[0001] This patent application claims the benefit of U.S. Provisional Patent Application No. 62 / 076,001, filed on September 9, 2020, claims the benefit of U.S. Patent Application No. 17 / 470771, filed on September 9, 2021, and claims the benefit of U.S. Patent Application No. 18 / 110,569, a partial continuation application, filed on February 16, 2023, the contents of each of which are hereby expressly incorporated by reference in their entirety, including any references therein.

[0002]

[0002] The present invention relates to a liquid ejection system, and more particularly, to a liquid ejection system having a nozzle for ejecting a controlled small amount of a highly viscous liquid.

Background Art

[0003]

[0003] In many industries, there is a need to eject a controlled small amount of a highly viscous liquid. In the food industry, for example, in the commercial production of pizza, it is necessary to eject an amount of a source in droplet sizes onto the pizza dough. Due to the gooey nature of the source, it is difficult to eject precisely controlled droplets quickly as desired. Further, it is desirable to eject such a source and other highly viscous liquids in relatively small droplets, but hitherto, it has been difficult to eject such small droplets on a rapid and repeatable basis. If the source contains solids that can clog the nozzle passage, the size of the flow path has to be increased, making the control of the ejection of small droplets even more difficult and often resulting in undesirable splashing of the ejected source. Further, when the ejection device uses an air - actuated liquid control piston, the rapid actuation of the piston is limited by the compressibility of the control air. Further, when the air - actuated device is spring - returned, the spring return force may be limited to about half of the force of the air pressure used to open the device, which inhibits rapid piston closure.

Summary of the Invention

[0004]

[0004] The object of the present invention is to provide a liquid dispensing system having a spray nozzle that is effective in reliably dispensing a small amount of highly viscous liquid with precisely controlled droplet size.

[0005]

[0005] Another objective is to provide a liquid dispensing system characterized above that is effective for rapidly depositing precisely controlled, pixel-sized droplets without undesirable splashing of liquid.

[0006]

[0006] A further objective is to provide the above-described liquid dispensing system in which the spray nozzle can operate in a larger inlet passage that is less susceptible to clogging by solid particles in the liquid.

[0007]

[0007] Another objective is to provide such a liquid dispensing system that can be selectively operated to dispense small, precisely controlled droplets of different sizes.

[0008]

[0008] Another objective is to provide such a liquid dispensing system that can operate more quickly.

[0009]

[0009] A further objective is to provide a liquid discharge system of such type having a pneumatically operated piston with a return spring whose action resists less the air pressure used to operate the system.

[0010]

[0010] Another objective is to provide the aforementioned type of liquid dispensing system that is relatively simple in design and suitable for economical manufacturing and efficient use.

[0011]

[0011] Other objects and advantages of the present invention will become apparent by referring to the drawings and reading the following detailed description. [Brief explanation of the drawing]

[0012] [Figure 1]This is a partial perspective view of an exemplary modular liquid dispensing system according to the present invention. [Figure 2] This is a perspective view of a fully assembled liquid dispensing system. [Figure 3] This is a vertical cross-sectional view of one of the liquid dispensing modules of the liquid dispensing system shown in the illustration. [Figure 4] Figure 3 is an enlarged vertical cross-sectional view of the central liquid control piston assembly of the liquid discharge module. [Figure 5] This is an enlarged perspective view of a vertical cross-section of one of the spray nozzle assemblies in the liquid discharge module of the illustrated system. [Figure 6] Figure 5 is a vertical cross-sectional view of the spray nozzle assembly shown. [Figure 7] Figures 5 and 6 show exploded perspective views of the spray nozzle assembly. [Figure 8] This is a schematic diagram of the solenoid control valve associated with each liquid discharge module. [Figure 9] This is an expected vertical cross-sectional view of an enlarged alternative embodiment of the spray nozzle assembly according to the present invention. [Figure 10] Figure 9 shows a vertical cross-sectional view of the spray nozzle assembly. [Figure 11] Figures 9 and 10 show the expected exploded view of the spray nozzle assembly. [Modes for carrying out the invention]

[0013]

[0023] While various modifications and alternative configurations are possible for this invention, specific exemplary embodiments are shown in the drawings and described in detail below. However, it should be understood that the invention is not intended to be limited to the specific forms disclosed, but rather to encompass all modifications, alternative structures, and equivalents that fall within the spirit and scope of the invention.

[0014]

[0024] Referring more closely to Figures 1 to 3 of the drawings, an exemplary liquid dispensing system 10 according to the present invention is shown. The illustrated liquid dispensing system 10 is in the form of a modular valve manifold 11 comprising a plurality of individual liquid dispensing modules 12 sealed, stacked, and supported and held in a side-by-side relationship between end blocks 13 and 14 at both ends, which are fixed to each other by tie rods 15 and nuts 16. Each module 12 includes a module nozzle support 20 in which a liquid supply port 21 is formed, which is aligned with the liquid supply port 21 of the adjacent module 12 in order to define a common liquid supply passage 22 communicating between the liquid inlet port 23 of the upstream end block 13 and the liquid outlet port 24 of the downstream end block 14. Thus, liquid toward the inlet 23 is transmitted through each of the stacked modules 12.

[0015]

[0025] Each illustrated module 12 has its own spray nozzle 30 mounted in relation to the lower side of the module nozzle support 20, and the spray nozzle has an upstream liquid inlet 31 on its upper side that communicates with the liquid supply passage 22. To control the liquid flow from the common liquid supply passage 22 of the modules 12 to the spray nozzle inlet 31, a piston 32 is supported within each module body 20 above the spray nozzle inlet 31 to reciprocate between a raised inlet open position and a lowered inlet closed position.

[0016]

[0026] In this case, each piston 32 is supported to move selectively relative to another within a carrier 33 that is fitted in a sealed relationship within the vertical opening 34 of the respective module body 20, and the downstream end of the piston 32 extends through a liquid supply passage 22 to engage with the spray nozzle inlet 31. To bias the piston 32 to a lowered position that closes the spray nozzle inlet 31, a return spring 35 is located in a spring chamber 36 of the module body 20, interposed between the head 32a of the piston 32 and a retaining sleeve 37 that is fixed within the upper end of the body opening 34 and held by a retaining cap 38 that is screwed into the upper end of the body opening 34. In this case, the retaining sleeve 37 extends downward around the return spring 35 and the piston head 32a, as best shown in Figures 3 and 4. In this case, the spring retaining sleeve 37 and the opening 34 of the module body 20 define an annular air passage 40 around the retaining sleeve 37 (Figure 3) that communicates through the spring chamber 36 via holes 41 in the circumferential transverse branches of the spring retaining sleeve 37. The sealed piston chamber 42 is defined between the opposing axle ends of the piston head 32a and the carrier 33 (Figure 4).

[0017]

[0027] According to an important feature of this embodiment, each module body has a pressurized air passage system controlled by respective valves such that the pressurized air that moves the piston to the open position also increases the rapid movement of the piston for closing. In the illustrated embodiment, the operation between the open and closed positions of the piston 32 of each module 12 is controlled by respective solenoid valves 43, as best shown in FIGS. 3 and 8. Each module solenoid valve 43 is attached to its respective module body 20 with the solenoid mounting block 44 attached in a sealed relationship to its respective module body 20 by screws 45. Each of the module bodies 20 has an air supply port 50 aligned with the air supply port 50 of each adjacent module body and defines a common air inlet passage that communicates with the system air inlet port 51 of the end block 14. Each of the module bodies 20 further has an air outlet port 52 aligned to define a common outlet air passage that communicates with the system exhaust outlet port 53 within the end block 14. The air supply port 50 of the module body 20 communicates with the air inlet port 55a of the solenoid valve 43 via inlet air passages 63, 63a within the module body 20 and the solenoid mounting block 44. The air outlet port 52 of the module body 20 communicates with the return spring chamber 36 through the outlet passage 60 via the hole 41 in the retaining sleeve 37 and the annular passage 40 around the sleeve 37, and the outlet passages 61, 61a within the solenoid mounting block 44 having the exhaust port 55b of the module body 20 and the solenoid valve 43. The piston chamber 42 communicates with the working port 55c of the solenoid control valve 43 via working passages 62, 62a within the module body 20 and the solenoid mounting block 44.

[0018]

[0028] When the solenoid valve 43 is in its natural or non-energized state, the inlet pressure at the solenoid valve port air inlet 55a is blocked by the mechanism 43a of the solenoid valve 43, in this case in the form of a stem (FIG. 8), and the pressurized air at the air supply port 50 of the module body 20 is prevented from communicating with the piston chamber 42 via the passageways 62a, 62 within the solenoid mounting block 44 and the module body 20. Another passage route when the solenoid valve 43 is in its natural or non-energized state connects the ports 55c, 55b of the solenoid valve 43 and allows air communication between the piston chamber 42 and the outlet port 52 within the module body 20 via the passageways 62, 62a within the module body 20 and the solenoid mounting block 44, the outlet passageways 61a, 61 within the solenoid mounting block 44 and the module body 20, the annular passage 40 passing around the spring 35 via the hole 41, and the outlet passage 60.

[0019]

[0029] When the solenoid valve 43 is energized, the solenoid moves the actuating mechanism 43a to close the exhaust port 55b, removes the connection to the atmosphere at port 55c, and connects the solenoid valve ports 55a, 55c. Then, the pressurized air at the air supply port 50 of the module body 20 communicates with the pressure chamber 42 via the passageways 63, 63a within the module body 20 and the solenoid mounting block 44, the solenoid valve ports 55a, 55c, and the passageways 62a, 62, strokes the piston 32 upward, opens the nozzle inlet 31, and compresses the return spring 35. The upward stroke of the piston head 32a gives an actual air displacement within the spring chamber 36, resulting in a slight pressure increase. The pressure that has risen within the spring cavity 36 gradually decreases to atmospheric pressure through the hole 41 of the spring retaining sleeve 37, the annular passage 40, the outlet passage 60, and the air outlet port 52 (FIGS. 3 and 4). While the solenoid is energized, the nozzle inlet 31 remains open, allowing liquid flow from the common liquid supply passage 22 through the spray nozzle 30 to the atmosphere.

[0020]

[0030] When de-energized, the solenoid valve 43 returns to its natural state. The inlet air pressure of the solenoid port 55a is shut off again, preventing pressurized air from entering the device. The rapid depressurization of the pressurized air in the piston chamber 42 causes a movement of high pressure in the passages 62, 62a in the module body 20 and the solenoid mounting block 44, ports 55c, 55b of the solenoid valve 43, outlet passages 61a, 61 in the solenoid mounting block 44 and the module body 20, the spring chamber 36, outlet passage 60, and outlet port 52, as the system pressure in the piston chamber 42 is released and equalized with the atmosphere. The moving pressure within the annular passage 40 is transmitted through the hole 41 in the spring retaining sleeve 37, creating a high pressure within the spring chamber 36, which acts on the surface area of ​​the piston head 32a within the spring chamber 36. As a result, a momentary downward force is generated that complements the constant downward force from the return spring 35, which is opposite to the decreasing pressure within the piston chamber 42, returning the piston 32 to its natural state, closing the passage 31, and stopping the flow of liquid from the common liquid supply passage 22 through the spray nozzle 30. The considerable reduction in the time required to return the piston 32 to its natural state is due to the momentary increase in pressure within the spring chamber 36. All passages and cavities downstream of the solenoid valve 43, including the spring chamber 36, are essentially returned to atmospheric pressure through the outlet port 52, effectively removing the additional force of the temporary pressure applied to the piston head 32a.

[0021]

[0031] Further operation of the liquid discharge module 12 by re-energizing the solenoid 43 allows the increased pressure to have the desired effect on the opening stroke of the piston 32 without being affected by the increased pressure from the previous iterative operation in the spring chamber 36, as the increased pressure is temporary and quickly returns to atmospheric pressure, and does not affect the closing stroke of the piston 32. As will become clear, the solenoid valve 43 can be iteratively operated at a predetermined speed for a particular discharge operation in which the variable opening time of the piston 32 results in a variable pixel volume.

[0022]

[0032] In a further aspect of this embodiment, each spray nozzle module 12 operates to discharge controlled, small, circular, pixel-sized droplets of highly viscous liquid in conjunction with the repetitive motion of the piston 32, even when the liquid has a considerable solid content. Referring particularly to Figures 5, 6, and 7, each spray nozzle 30 in this case comprises a nozzle body 70, a nozzle base 71, and an internal nozzle core 72. The nozzle base 71 in this case has an externally threaded cylindrical downstream end 73 which is screwed into the upstream cylindrical end 74 of the nozzle body 70 to secure the nozzle core 72 within the nozzle body 70. The upstream end 75 of the nozzle base 71 defines a predetermined-sized liquid inlet 31 at the upstream end of the assembly. In this example, the nozzle core 72 has an upstream cylindrical mounting flange 78 which is positioned on an annular projection 79 within the nozzle body 70 and held in place by the nozzle base 71, although it will be understood that other methods may be used to secure the nozzle core 72 within the nozzle body 70.

[0023]

[0033] The cylindrical mounting flange 78 of the core 72 has a downstream end wall 80 that is concave (with respect to the direction of fluid flow) and forms a plurality of circumferentially spaced and axially oriented liquid orifices 81. These liquid orifices, which communicate the expansion cavity 82 of the nozzle base 71 with the liquid discharge passage defined and annularly configured between the nozzle core 72 and the nozzle body 70, guide the liquid in a controlled manner for optimal discharge in the form of small droplets, as will become apparent. The illustrated nozzle 30 comprises an assembly of multiple parts, but it will be understood that it may instead be a single-piece structure or of fewer or more assembled parts.

[0024]

[0034] In carrying out this aspect of this embodiment, the nozzle core 72, together with the inner surface of the surrounding nozzle body 70, has a teardrop-shaped pintle 83 that defines a widening discharge passage 85, reducing the outlet velocity of the discharged liquid in order to maintain a desired flow rate and a constant droplet size of the highly viscous discharge liquid. For this purpose, the illustrated pintle 83 (see Figures 5, 6, and 7) has a relatively small-diameter upstream end section 86 extending centrally from the mounting flange 78, a curved section 87 extending radially outward adjacent to the upstream end, and a relatively long, tapered conical end section 90. As described above, the nozzle body 70 has a substantially hollow cylindrical shape, with the inner surface of the nozzle body 70 defining the outer wall of the annular discharge passage 85 around the core section 72. The inner wall of the discharge passage 85 is defined by the outer surface of the pintle 83. In this case, the inner surface of the nozzle body 70 includes a radially outward-facing section 91 extending circumferentially to the outward-facing curved section 87 of the nozzle core 72, and a section 84 of uniform diameter extending downstream, which is substantially the remaining length of the pintle 83. This design is unique in that the flow through the annular discharge passage causes the viscous liquid to expand inward as it moves through the nozzle body. The geometric shape of the pintle defines the inner diameter wall of the annular flow path and provides a structure that can create a vacuum due to the expansion of the flow. The deceleration of the liquid in the expanding annular discharge passage is due to the action of surface tension and the ability of capillary forces to create a vacuum and resist the flow.

[0025]

[0035] During operation, continuing to refer to Figure 3, when the piston 32 is in the raised inlet-open position, the liquid can pass through the nozzle inlet 31 in a controlled manner and enter the expansion cavity 82 defined within the cylindrical downstream end of the nozzle base 71. The liquid passing through the nozzle inlet 31 is guided to a collision surface defined by the concave downstream end wall 80 of the expansion cavity 82. This fills the expansion cavity 82, and the liquid is then pushed out of the expansion cavity through a series of circumferentially spaced orifices 81 into the discharge passage 85. Furthermore, the size of each orifice 81 is at least the same as the nozzle inlet 31 in order to allow solid particles in the liquid to flow from the expansion cavity 82 to the fluid discharge passage 85 without clogging. The combined area of ​​the circumferentially spaced orifices 81 is larger than the area of ​​the nozzle inlet 31, such that the velocity of the liquid passing through the orifices 81 is inversely proportional to the ratio of the size of the orifices 81 to the size of the nozzle inlet 31.

[0026]

[0036] More specifically, the circumferential orifice 81 at the downstream end of the expansion cavity 82 communicates with the inlet section 92 of the discharge passage 85, which is defined between the outward-facing wall section 91 of the nozzle body 70 and the pintle 83 of the nozzle core 72. The cross-sectional area of ​​the annular inlet section 92 may increase as the section extends downstream, and as a result, the fluid velocity in this region continues to decrease as the cross-sectional area of ​​the discharge passage expands. A slight decrease in the cross-sectional area of ​​the discharge passage 85 in the stabilization section 93 of the discharge passage 85 immediately downstream of the inlet section 92 (also defined by the outer surface of the pintle 83 and the inner circumferential surface of the nozzle body 70) can result in a slight increase in pressure. This increase in pressure stabilizes and balances the flow, eliminating individual jet flows caused by the fluid entering the inlet section 92 of the discharge passage 85 through a series of orifices 81, and allowing for a uniform flow along the inner wall surface of the nozzle body 70. The cross-sectional area of ​​the stabilization section 93 remains constant throughout this region to allow the fluid to stabilize.

[0027]

[0037] Downstream of the stabilization section 93, the liquid enters the final expansion section 95, defined by a tapered end section 90 inside the nozzle core 72, which extends downstream to the nozzle opening 94 defined at the downstream end of the nozzle body 70. The gradually increasing cross-sectional area of ​​the final expansion section 95 is achieved by decreasing the conical diameter of the pintle 83 of the end section 90, while simultaneously maintaining a constant diameter for the inner circumferential surface of the nozzle body 70. The pintle 83 helps to stabilize the fluid and allows for greater liquid expansion than could be achieved with a nozzle core having a simple, uniform diameter. The sustained contact between the liquid and the inner and outer walls of the discharge passage is due to the action of the liquid's surface tension.

[0028]

[0038] The cross-sectional area of ​​the final expansion section 95 at the nozzle opening 94 determines the exit velocity of the liquid, which is inversely proportional to the cross-sectional area at the nozzle opening relative to the area of ​​the nozzle inlet 31. The terminal section 90 of the nozzle core 72 preferably extends slightly beyond the nozzle opening 94 to help break the surface tension of the liquid against the inner circumferential surface of the nozzle body 70 without affecting the outer diameter of the discharged liquid flow. Making the inner circumferential surface of the nozzle body 70 a constant diameter helps the liquid boundary layer to form a constant diameter as the liquid exits the nozzle, which helps maintain a desired droplet diameter regardless of the distance of the nozzle from the target.

[0029]

[0039] It has been found that a dramatic reduction in the velocity of the liquid can be achieved by gradually increasing the cross-sectional area of ​​the discharge passage 85. The inward expansion of the discharge passage 85 is achieved by gradually decreasing the diameter of the pintle 83 while maintaining the inner circumferential surface of the nozzle body 70. This helps to produce discharge liquid with a constant flow diameter. By reducing the velocity of the liquid, it becomes possible to discharge it without splashing. This further allows for the use of a larger nozzle inlet orifice 31 to enable the discharge of liquid with a larger solid content. Once the discharge passage of the nozzle is initially filled with viscous fluid, the surface tension of the liquid keeps the nozzle 30 filled with liquid ready to be discharged when the nozzle inlet 31 is opened. Since the liquid can be substantially incompressible, a precise relationship can be maintained between the volume of liquid entering the nozzle 30 through the inlet 31 and the liquid exiting the nozzle opening 94. It has been found that repeatedly moving the piston 32 to open and close the inlet orifice 31 at a high speed, such as 50 milliseconds, produces small, constant droplets that are discharged at a reduced outlet velocity. This allows the discharged droplets to be deposited onto a target, such as a target approximately 2 inches from the nozzle, without scattering.

[0030]

[0040] Referring to Figures 9 to 11, alternative embodiments of the spray nozzle 100 are shown, which are effective for rapidly dispensing small, inconspicuous droplets of highly viscous liquids. In this case, the spray nozzle 100 also comprises a nozzle body 101, a nozzle base 102, and an internal nozzle core 104. The same parts as above are denoted by the same reference numerals. Again, although the illustrated spray nozzle assembly 100 comprises an assembly of multiple parts, it will be understood that it may instead be a single-piece structure or made up of fewer or more assembled parts.

[0031]

[0041] In this embodiment, the nozzle base 102 is also fixed within the upstream end 74 of the nozzle body 101, defining the liquid inlet 31, and the nozzle core 104 is held in place by the nozzle base 102 and has an upstream cylindrical mounting flange 78 located within the nozzle body 101. The upstream cylindrical mounting flange 78 of the nozzle core 104 also has a concave upstream end wall 80 which forms a plurality of circumferentially spaced and axially oriented liquid orifices 81. The orifices 81 communicate between the expansion cavity 82 in the nozzle base 102 between the liquid inlet 31 of the nozzle base and the nozzle core 104 and the annular passage 92 defined between the internal cylindrical wall section 106 of the nozzle body 101 and the pintle 83 of the nozzle core 104. In this case, the radially outer side of the liquid orifices 81 of the mounting flange is aligned with the internal cylindrical wall section 106 of the nozzle body.

[0032]

[0042] The pintle 83 of the nozzle core 104 also has a teardrop shape, which, together with the internal cylindrical wall section 106 of the nozzle body 101, defines an annular channel 85 that reduces the velocity of the liquid discharged as it moves through the nozzle body 101. Similar to the previous embodiment, the illustrated pintle 83 has a relatively small-diameter upstream end section 86 extending centrally from the mounting flange 78, a curved section 87 extending radially outward adjacent to the upstream end, and a relatively long, tapered conical end section 90 that, together with the internal cylindrical nozzle wall section 106 of the nozzle body 101, defines an expansion section 95 of the annular channel 85. The geometric shape of the pintle 83 also defines the inner diameter wall of the annular channel 85 and provides a structure that can form a vacuum due to the expansion of the flow. The deceleration of the liquid in the expansion section 95 of the annular channel 85 is, again, the action of surface tension and the ability of capillary forces to create a vacuum and resist the flow.

[0033]

[0043] A key feature of this embodiment is that the spray nozzle 100 is designed to accelerate a highly viscous liquid sufficiently to facilitate the rapid discharge of even smaller, carefully controlled droplets upon discharge from the spray nozzle. For this purpose, the widening annular channel 85 between the nozzle body cylindrical wall section 106 and the pintle 83 communicates with a reduced-diameter discharge orifice 110 of the spray nozzle, sized to accelerate the liquid sufficiently to enable the repeated discharge of inconspicuous, small droplets. In the illustrated embodiment, the nozzle body 101 has an inwardly tapered downstream section 111 that defines the discharge orifice 110, which is smaller in diameter than the cylindrical wall section 106. Alternatively, it will be understood that a separate spray tip may be attached to the downstream end of the cylindrical wall section 106 of the nozzle body 101 to define the discharge orifice 110. In this case as well, the downstream end of the conical pintle section 90 extends a short distance beyond the spray nozzle's discharge orifice 110 in order to define an annular discharge passage 113 between the nozzle body discharge orifice 110 and the pintle conical section 90.

[0034]

[0044] The widening annular channel 85 reduces the flow of liquid through the spray nozzle 100, but the smaller diameter discharge orifice 110 and the resulting smaller diameter annular discharge passage 113 were unexpectedly found to accelerate the liquid discharge sufficiently to facilitate careful separation of small droplets during the repeated operation of the spray nozzle 100. As in the previous embodiment, the widening annular channel 85 reduces the velocity of the fluid flow through the spray nozzle 100, but the reduced diameter discharge orifice 110 and the resulting smaller size annular channel 113 result in a rapid movement between the widening annular channel 85 and the atmosphere beyond the spray nozzle 100, thereby providing an intrinsic separation between the fluid confined and held within the nozzle body 101 and the inertia that discharges the fluid from the spray nozzle, resulting in reliable discharge of small, inconspicuous droplets.

[0035]

[0045] The relationship between the area of ​​the inlet passage 31 and the area of ​​the annular discharge passage 113 can be controlled based on the viscosity of the liquid being discharged to ensure droplet separation without excessive acceleration that would cause undesirable splashing of the liquid. In one embodiment, particularly applicable for dispensing pizza sauce, the ratio of the area of ​​the annular passage 113 to the area of ​​the inlet 31 of the spray nozzle, resulting in an accelerated velocity, is 5:1. Thus, the fluid velocity at discharge is reduced to 1 / 5 or 20% of the liquid velocity at the inlet 31. In such cases, the accelerated discharge of the viscous liquid at the discharge orifice 110 facilitates the reliable separation of the discharged droplets without excessive velocity that would cause splashing of the discharged droplets. In one embodiment, the nozzle body discharge orifice may have a diameter of 0.285 inches, but other embodiments may have discharge orifices of different sizes depending on the relationship between the resulting area of ​​the annular passage 113 and the liquid inlet 31 and the viscosity of the particular liquid being discharged.

[0036]

[0046] During operation, once the empty passage within the spray nozzle 100 is initially filled with viscous liquid, the fluid surface tension will be found to maintain the nozzle in a state where it is filled with fluid prepared to be discharged from the discharge passage 113. The incompressibility of the fluid maintains a precise relationship between the fluid entering the spray nozzle through the inlet 31 and the fluid exiting the annular discharge passage 113. The repetitive action of the popit or control piston to rapidly open and close the inlet 31 generates small, constant fluid jerk at a rate that facilitates droplet separation without scattering the discharged liquid.

[0037]

[0047] Therefore, the subject spray nozzle 100 was able to achieve the discharge of a smaller and more constant volume of the uncontrollable liquid. The extension resulting from the fluid change between the slow internal velocity in the expansion section 95 and the increased velocity accompanying the discharge from the smaller-sized discharge orifice 110 and annular channel 113 unexpectedly resulted in a more constant and repeatable interruption of the discharged fluid flow. The 5:1 area ratio between the annular discharge passage 113 and the liquid inlet 31 was found to work best for fluids with a viscosity typical of pizza sauce, but it will be understood that the ratio can be easily adjusted to accommodate different liquids. The optimal volume ratio between the annular passage 113 and the liquid inlet 31, which can be adjusted for the specific fluid being discharged, will be understood to be a balance between the desired constant and repeatable interruption of the fluid during discharge and the undesirable splashing due to excessive velocity.

Claims

1. It is a spray nozzle, Nozzle base with liquid inlet for connection to a repetitively operating liquid supply source, A nozzle body having a roughly hollow cylindrical shape, and An internal nozzle core disposed within the nozzle body, The nozzle body includes an expansion chamber that connects the liquid inlet and the nozzle core, The nozzle core has an upstream end adjacent to the downstream end of the expansion chamber and a teardrop-shaped pintle extending downstream of the upstream end, the pintle having a radially outward curved section adjacent to the upstream end and a radially tapered conical end section, The nozzle body has an internal cylindrical wall section that defines an expanding annular flow path that communicates fluid with the expansion cavity, along with a tapered conical end section located radially inward of the pintle. A spray nozzle having a downstream discharge orifice smaller in diameter than the cylindrical wall section for accelerating the liquid discharged from the discharge orifice in order to facilitate the splitting of the discharged liquid into small, inconspicuous droplets in conjunction with the repeated supply of liquid to the nozzle base liquid inlet.

2. The spray nozzle according to claim 1, wherein the pintle, together with the nozzle body discharge orifice, has a downstream end that defines an annular discharge passage between the nozzle body discharge orifice and the pintle.

3. The spray nozzle according to claim 2, wherein the pintle extends downstream beyond the nozzle body discharge orifice.

4. The spray nozzle according to claim 2, wherein the ratio of the area of ​​the annular discharge passage of the nozzle body to the area of ​​the liquid inlet of the nozzle base is 5:

1.

5. The spray nozzle according to claim 1, wherein the nozzle body has a tapered end on the inside that defines the nozzle body discharge orifice.

6. The spray nozzle according to claim 2, wherein the diameter of the nozzle body discharge orifice is 0.285 inches.

7. The spray nozzle according to claim 1, wherein the nozzle core has an upstream mounting flange having a plurality of liquid flow orifices formed thereon, which are spaced apart in the circumferential direction and communicate between the expansion chamber and the expanding annular passage.

8. The spray nozzle according to claim 7, wherein the upstream end of the cylindrical wall section inside the nozzle body is aligned with the outer circumference of liquid flow orifices that are spaced apart in the circumferential direction of the nozzle core.

9. The spray nozzle according to claim 1, wherein the nozzle base, nozzle body, and nozzle core are separate, inconspicuous parts assembled together.

10. It is a spray nozzle, Nozzle base with liquid inlet for connection to a repetitively operating liquid supply source, A nozzle body having a substantially hollow cylindrical shape that defines an internal cylindrical wall section, An internal nozzle core disposed within the nozzle body, The nozzle body includes an expansion chamber that connects the liquid inlet and the nozzle core, The internal nozzle core includes a teardrop-shaped pintle having an upstream end section adjacent to the downstream end of the expansion cavity, a radially outward curved section adjacent to the upstream end section, and a radially tapered conical end section. A spray nozzle having a nozzle body having a discharge orifice surrounding the downstream end section of the pintle to define an annular discharge passage between them, wherein the nozzle body discharge orifice is smaller in diameter than the cylindrical wall section to accelerate the liquid discharged from the annular discharge passage in order to facilitate the splitting of the discharged liquid into small, inconspicuous droplets as the liquid is repeatedly supplied to the nozzle base liquid inlet.

11. The spray nozzle according to claim 10, wherein the ratio of the area of ​​the annular discharge passage of the nozzle body to the area of ​​the liquid inlet of the nozzle base is 5:

1.

12. The spray nozzle according to claim 10, wherein the nozzle body has a tapered end on the inside that defines the discharge orifice.

13. The spray nozzle according to claim 10, wherein the nozzle core has an upstream mounting flange having a plurality of liquid flow orifices formed thereon, which are spaced apart in the circumferential direction and communicate between the expansion chamber and the expanding annular passage.

14. The spray nozzle according to claim 13, wherein the nozzle core mounting flange has a concave upstream side oriented in the direction of liquid movement.

15. The spray nozzle according to claim 13, wherein the internal cylindrical wall section of the nozzle body extends to the outer circumference of liquid flow orifices arranged at intervals in the circumferential direction of the nozzle core and is aligned with the outer circumference.

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