Low-pressure nozzle structure used in spraying system

Abstract

The invention discloses a low-pressure nozzle structure used in a spraying system. The low-pressure nozzle structure comprises a nozzle seat, a nozzle column, a nozzle sheath, a nozzle column handle and a nut, and a nozzle assembly is arranged in the nozzle column; the nozzle assembly comprises a nozzle head, an auxiliary nozzle head and a positioning ring, the nozzle head is internally provided with a strengthening channel and a linear shearing outlet, the auxiliary nozzle head is internally provided with a strengthening channel, the strengthening channel and the pressurizing channel form a secondary flow field strengthening and enhancing unit, the positioning ring is internally provided with a first pre-focusing section, and the first pre-focusing section forms a cavitation initial rising cavity; the pressurization channel comprises a secondary pressurization pipe section, a primary expansion cone section and a secondary expansion cone section, and the strengthening channel comprises a second pre-coking section, a correction flow guide curved surface section and a liquid phase boundary layer control section. The two-stage flow field strengthening unit is adopted, and two-time ordered excitation and strengthening of the cavitation effect are achieved; the energy efficiency is high, the reliability is strong, and the compatibility and the economical efficiency are good.

Description

TECHNICAL FIELD

[0001] The present application relates to the nozzle technical field, specifically relates to a low pressure nozzle structure for spraying system. BACKGROUND

[0002] Fluid ejection systems are commonly used in a variety of applications from industrial assembly to household paint spraying. Fluids ejected by such systems conform to a spray pattern defined by the shape and size of the orifice to a large extent. Different nozzle tips having different shapes and sizes of orifices can be positioned in the fluid ejection system to change the spray pattern of the fluid ejected by the fluid ejection system.

[0003] The internal structure of a common nozzle flow channel is composed of two parts, the first part is a spraying fluid feeding channel, and the second part is a spraying fluid atomization component. The inner hole of the spraying fluid feeding channel is a common circular through hole, which only plays a drainage role of transmitting the spraying fluid, and transmits the spraying fluid into the fluid chamber of the atomization component, the fluid enters the outlet channel of the atomization component, and finally forms atomized spraying through the outlet hole formed by the tip grinding.

[0004] However, the existing atomization component channel has the following defects: the atomization mechanism is single: most low pressure nozzles only rely on primary expansion cavitation atomization, the energy utilization rate is low, the atomization limit is limited, and it is difficult to produce fine and uniform spraying. The flow field control is rough: the transition of the internal flow channel is often sharp or large round, lacks precise design, is easy to produce flow separation, vortex and energy dissipation, not only reduces the atomization efficiency, but also causes cavitation erosion, resulting in early failure of the nozzle. It is necessary to improve the existing structure design. SUMMARY

[0005] The purpose of the present application is to solve the problems raised in the background art, and to provide a low pressure nozzle structure for a spraying system.

[0006] To solve the above technical problems, the technical scheme of the present application is as follows: a low pressure nozzle structure for a spraying system, comprising a nozzle seat, a nozzle column, a nozzle sheath, a nozzle column handle and a nut, a nozzle assembly is arranged in the nozzle column; the nozzle assembly comprises a nozzle head, an auxiliary nozzle head and a positioning ring, the nozzle head is respectively provided with a reinforced channel and a linear shear outlet, the auxiliary nozzle head is provided with a pressurization channel, the reinforced channel and the pressurization channel form a two-stage flow field reinforced enhancement unit, and the positioning ring is provided with a first pre-focusing section, and the first pre-focusing section forms a cavitation initial rising cavity; the pressurization channel comprises a two-stage pressurization pipe section, a primary expansion cone section and a secondary expansion cone section, the taper of the primary expansion cone section is smaller than that of the secondary expansion cone section, and the reinforced channel comprises a second pre-focusing section, a correction flow guide curved surface section and a liquid phase boundary layer control section.

[0007] In the low-pressure nozzle structure for a spraying system, the nozzle seat is provided with a nozzle cap assembly corresponding to the nozzle assembly, the nozzle cap assembly comprises a primary nozzle cap and a rubber plug, the rubber plug is fixedly installed in the primary nozzle cap in the nozzle seat, and the primary nozzle cap is abutted and fixed to the nozzle assembly, and the primary nozzle cap is provided with a primary expansion cone section.

[0008] In the low-pressure nozzle structure for a spraying system, the nozzle cap assembly further comprises a nozzle cap insert, the nozzle cap insert is provided with a primary expansion transition cone section and a primary booster pipe section, the primary expansion cone section, the primary expansion transition cone section and the primary booster pipe section form a primary flow field development cavity, the primary flow field development cavity and the cavitation initial rising cavity form a primary flow field strengthening enhancement unit, and the taper of the primary expansion transition cone section is greater than the taper of the primary expansion cone section.

[0009] In the low-pressure nozzle structure for a spraying system, the primary expansion cone section is abutted to the end of the secondary booster pipe section, and the end of the secondary booster pipe section is provided with an inter-stage flow state mixing promotion curved surface.

[0010] In the low-pressure nozzle structure for a spraying system, the correction flow guide curved surface section comprises a linear correction curved surface section and an anti-separation flow guide curved surface section.

[0011] In the low-pressure nozzle structure for a spraying system, the inter-stage flow state development curved surface is arranged at the joint between the secondary booster pipe section and the primary expansion cone section.

[0012] In the low-pressure nozzle structure for a spraying system, the secondary anti-cavitation flow guide curved surface is arranged at the joint between the primary expansion cone section and the secondary expansion cone section.

[0013] In the low-pressure nozzle structure for a spraying system, the liquid phase boundary layer control section is provided with an annular flow type forging cavity at the end abutting to the linear shear outlet.

[0014] In the low-pressure nozzle structure for a spraying system, the primary flow line type flow guide curved surface is arranged at the joint between the primary expansion transition cone section and the primary booster pipe section.

[0015] In the low-pressure nozzle structure for a spraying system, the ends abutting to both the secondary expansion cone section and the second pre-focus section are symmetrically abutted in a bell mouth shape.

[0016] In the low-pressure nozzle structure for a spraying system, the ends abutting to both the primary expansion cone section and the first pre-focus section are symmetrically abutted in a conical shape.

[0017] The low-pressure nozzle structure for a spraying system has the following beneficial effects: The secondary flow field strengthening unit is innovatively adopted to realize twice orderly excitation and enhancement of cavitation effect; the spraying medium experiences four atomization processes of "primary cavitation atomization, secondary enhanced cavitation atomization, mechanical shearing atomization and pneumatic atomization", and finally forms spraying particles with smaller size, more uniform distribution (excellent monodispersity) and high surface quality coating.

[0018] High energy efficiency and high reliability: the full flow passage adopts multiple functional transition surfaces (such as anti-separation guide surface and streamline correction surface) based on the principle of fluid mechanics to accurately control the flow field; ① significantly reduces flow separation and turbulent dissipation, and more efficiently uses fluid pressure energy for atomization itself, to obtain better performance under the same pressure. ② fundamentally suppresses the initial generation of cavitation phenomenon in the key stress area (such as the nozzle exit), greatly prolongs the service life of the nozzle.

[0019] Good compatibility and economy (modularization): the nozzle cap assembly can be used in combination with other conventional nozzles, and the core atomizing flow passage of the application is integrated. The user does not need to replace the entire spraying system, but only needs to install the nozzle cap of the application to significantly upgrade the atomization effect of the existing equipment, reduce the use cost and provide greater flexibility. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is an exploded view of the application; Figure 2 is an exploded view of the application in another direction Figure 3 is a sectional view of the application; Figure 4 is a partial structural sectional view of the application Figure 5 is Figure 4 is an enlarged view of A part in DETAILED DESCRIPTION

[0021] The application will be further described in conjunction with the drawings.

[0022] Please refer to Figures 1 to 5The application provides a low-pressure nozzle structure for a spraying system, which comprises a nozzle seat 1, a nozzle column 2, a nozzle sheath 3, a nozzle column handle 4, a nut 50, and a nozzle assembly arranged in the nozzle column 2; the nozzle assembly comprises a nozzle head 5, an auxiliary nozzle head 6 and a positioning ring 7; the nozzle head 5 is respectively provided with a reinforced channel 8 and a linear shear outlet 9, the linear shear outlet 9 is preferably designed in a V shape, the auxiliary nozzle head 6 is provided with a pressurizing channel 10, the reinforced channel 8 and the pressurizing channel 10 form a two-stage flow field reinforced enhancement unit 11, and the positioning ring 7 is provided with a first pre-focusing section 12, which forms a cavitation initial rising cavity 13; the pressurizing channel 10 comprises a two-stage pressurizing pipe section 14, a primary expansion cone section 15 and a secondary expansion cone section 16, the taper of the primary expansion cone section 15 is smaller than that of the secondary expansion cone section 16, and the reinforced channel 8 comprises a second pre-focusing section 17, a correction flow guide curved surface section 18 and a liquid phase boundary layer control section 19; and the whole nozzle structure is connected, installed and used through the nut 50.

[0023] Further, the nozzle seat 1 is provided with a nozzle cap assembly 20 corresponding to the nozzle assembly, the nozzle cap assembly 20 comprises a primary nozzle cap 21 and a rubber plug 22, the rubber plug 22 is fixedly installed in the nozzle seat 1 and the primary nozzle cap 21 is fixedly positioned against the nozzle assembly, and the primary nozzle cap 21 is provided with a primary expansion cone section 23.

[0024] Further, the nozzle cap assembly 20 further comprises a nozzle cap insert 24, the nozzle cap insert 24 is provided with a primary expansion transition cone section 25 and a primary pressurizing pipe section 26, the primary expansion cone section 23, the primary expansion transition cone section 25 and the primary pressurizing pipe section 26 form a primary flow field development cavity 27, and the primary flow field development cavity 27 and the cavitation initial rising cavity 13 form a primary flow field reinforced enhancement unit 28; and the taper of the primary expansion transition cone section 25 is greater than that of the primary expansion cone section 23.

[0025] Further, the primary expansion cone section 23 is butted against the end of the two-stage pressurizing pipe section 14, and the end of the two-stage pressurizing pipe section 14 is provided with an inter-stage flow state mixing promotion curved surface 29.

[0026] Further, the correction flow guide curved surface section 18 comprises a line correction curved surface section 30 and an anti-separation flow guide curved surface section 31.

[0027] Further, the interconnection between the two-stage pressurizing pipe section 14 and the primary expansion cone section 15 is provided with an inter-stage flow state development curved surface 32.

[0028] Further, the interconnection between the primary expansion cone section 15 and the secondary expansion cone section 16 is provided with a two-stage anti-cavitation flow guide curved surface 33.

[0029] Further, the end of the liquid phase boundary layer control section 19 and the linear shear outlet 9 is provided with an annular flow pattern forging cavity 34.

[0030] Further, the end of the primary expansion transition cone section 25 and the primary booster pipe section 26 is provided with a primary flow line guide surface 35.

[0031] Further, the end of the secondary expansion cone section 16 and the second pre-focus section 17 is provided with a horn mouth symmetrical junction.

[0032] Further, the end of the primary expansion cone section 23 and the first pre-focus section 12 is provided with a conical symmetrical junction.

[0033] The following further illustrates the principles of the present application: The inlet and primary booster nozzle, high pressure steady state region, pressure energy (P) begins to convert into kinetic energy (K), the flow rate rises, the static pressure drops, and the single continuous liquid phase. The fluid is an undisturbed continuous medium, and no atomization occurs.

[0034] The primary flow field development cavity (primary flow field strengthening enhancement unit) is the first pressure drop region. The flow passage is suddenly expanded, the flow rate drops, and according to Bernoulli's principle, the static pressure drops sharply below the saturation vapor pressure, forming a low pressure cavitation core region. The first phase change and atomization occur, cavitation effect occurs, a large number of cavitation bubbles are generated inside the fluid, the continuous liquid column is initially broken, and becomes a mixed two-phase flow of liquid droplets and gas bubbles (coarse atomization).

[0035] The cavitation initial rise cavity (primary flow field strengthening enhancement unit) is a primary converging section, and the pressure partially recovers. The flow passage is contracted, the flow rate rises, and the static pressure rises slightly, but is still lower than the inlet pressure. The two-phase flow rectification region collects and guides the turbulent two-phase flow after coarse atomization, and the mixture tends to be uniform, preparing for the next acceleration.

[0036] The secondary flow field strengthening enhancement unit, in which the secondary booster pipe section initially enters the second energy injection region in the booster channel. The cross section of the flow passage is suddenly reduced, the two-phase flow is accelerated by secondary pressurization, the kinetic energy is raised to a higher level, and the static pressure is lowered again. The two-phase flow energy is raised. The liquid droplets and gas bubbles are accelerated together, and part of the large gas bubbles may be broken due to shear, and the liquid droplet size is slightly refined.

[0037] The two-stage expansion cone section at both ends of the booster channel is a secondary flow field strengthening section, and the second pressure drop region. The pressure drops more sharply and more instantaneously than the first time, and the cavitation intensity reaches a peak. The second strengthening atomization. The cavitation effect is extremely enhanced, and the cavitation bubbles collapse violently, producing micro-jets and shock waves that further break the liquid droplets after primary atomization into finer particles (fine atomization), and the mixture is extremely uniform.

[0038] Reinforced channel (secondary flow field reinforcement unit) fluid dynamic focusing channel, pressure stable transition zone, pressure smooth change, flow rate continues to rise under the constraint of geometry, kinetic energy reaches peak. Flow pattern forging and laminarization, disordered two-phase turbulent flow is forged into orderly, stable, pre-formed liquid film. Boundary layer is controlled, phase state is uniform.

[0039] V-shaped linear shear outlet, energy final conversion zone. Pressure drops to ambient back pressure, the remaining energy is used to overcome surface tension (interface energy required to form new surface). Third atomization (mechanism change). Uniform liquid film is torn by V-shaped blade shear, broken into highly uniform size, distribution concentrated fine droplets (fine atomization). Atomization mechanism changes from "cavitation" to "mechanical shear".

[0040] External pneumatic atomization zone, pressure balance zone. Pressure balances with ambient atmospheric pressure. Fourth atomization (ultimate refinement). Speed droplet group collides with stationary air, based on We number (We) effect, secondary breakage occurs, finally forming extremely fine, uniform spray cloud.

[0041] The above has carried out the detailed introduction to the low pressure nozzle structure for the spraying system provided by the embodiment of the application, the principle and implementation mode of the application are described in this paper by applying specific examples, the above embodiment description is only for helping to understand the technical scheme disclosed by the application; at the same time, for the general technical personnel in the art, according to the idea of the application, the specific implementation mode and application range will have the change, according to the above, the content of the specification should not be understood as the limitation of the application.

Claims

1. A low pressure nozzle structure for use in a spray system comprising a nozzle seat (1), a nozzle stem (2), a nozzle sheath (3), a nozzle stem handle (4), a nut (50), a nozzle assembly is provided in the nozzle stem (2); characterized in that: The nozzle assembly comprises a nozzle head (5), an auxiliary nozzle head (6), a positioning ring (7), the nozzle head (5) is respectively provided with a reinforced channel (8) and a linear shear outlet (9), the auxiliary nozzle head (6) is provided with a pressurization channel (10), the reinforced channel (8) and the pressurization channel (10) constitute a two-stage flow field reinforcement enhancement unit (11), the positioning ring (7) is provided with a first pre-focusing section (12), and the first pre-focusing section (12) constitutes a cavitation initial rising cavity (13); the pressurization channel (10) comprises a two-stage pressurization pipe section (14), a primary expansion cone section (15) and a secondary expansion cone section (16), the taper of the primary expansion cone section (15) is smaller than that of the secondary expansion cone section (16), and the reinforced channel (8) comprises a second pre-focus section (17), a correction flow guide curved surface section (18) and a liquid phase boundary layer control section (19).

2. A low pressure nozzle structure for use in a spray system according to claim 1, characterized in that: The nozzle seat (1) is provided with a nozzle cap assembly (20) corresponding to the nozzle assembly, the nozzle cap assembly (20) comprises a primary nozzle cap (21) and a rubber plug (22), the rubber plug (22) is fixedly installed in the nozzle seat (1) and the primary nozzle cap (21) is abuttingly positioned and fixed to the nozzle assembly, and the primary nozzle cap (21) is provided with a primary expansion cone section (23).

3. A low pressure nozzle structure for use in a spray system according to claim 2, characterized in that: The nozzle cap assembly (20) further comprises a nozzle cap insert (24), the nozzle cap insert (24) is provided with a primary expansion transition cone section (25) and a primary pressurization pipe section (26), the primary expansion cone section (23), the primary expansion transition cone section (25) and the primary pressurization pipe section (26) constitute a primary flow field development cavity (27), the primary flow field development cavity (27) and the cavitation initial rising cavity (13) constitute a primary flow field reinforcement enhancement unit (28), and the taper of the primary expansion transition cone section (25) is greater than that of the primary expansion cone section (23).

4. A low pressure nozzle structure for use in a spray system according to claim 2 or 3, characterized in that: The primary expansion cone section (23) is butted with the end of the two-stage pressurization pipe section (14), and the end of the two-stage pressurization pipe section (14) is provided with an inter-stage flow state mixing promotion curved surface (29).

5. A low pressure nozzle structure for use in a spray system according to claim 1, wherein: The correction flow guide curved surface section (18) comprises a line correction curved surface section (30) and an anti-separation flow guide curved surface section (31).

6. A low pressure nozzle structure for use in a spray system according to claim 1, wherein: An inter-stage flow state development curved surface (32) is arranged at the joint between the two-stage pressurization pipe section (14) and the primary expansion cone section (15).

7. A low pressure nozzle structure for use in a spray system according to claim 1, wherein: A two-stage anti-cavitation flow guide curved surface (33) is arranged at the joint between the primary expansion cone section (15) and the secondary expansion cone section (16).

8. A low pressure nozzle structure for use in a spray system according to claim 1, wherein: An annular flow type forging cavity (34) is arranged at the end of the liquid phase boundary layer control section (19) connected with the linear shear outlet (9).

9. A low pressure nozzle structure for use in a spray system according to claim 3, wherein: A primary flow line type flow guide curved surface (35) is arranged at the joint between the primary expansion transition cone section (25) and the primary pressurization pipe section (26).

10. A low pressure nozzle structure for use in a spray system according to claim 3, wherein: The ends of the secondary expansion cone section (16) and the second pre-focus section (17) are symmetrically butted in a bell mouth.

11. A low pressure nozzle structure for use in a spray system according to claim 2 or 3, characterized in that: The ends of the primary expansion cone section (23) and the first pre-focusing section (12) are symmetrically butted in a taper.

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