High pressure liquid rotary nozzle with fluid speed limiting mechanism

Abstract

The high-pressure liquid nozzle housing houses a self-rotating speed-regulating nozzle. This nozzle assembly comprises a generally cylindrical housing, which serves as a relatively fixed reference structure. Inside, a coaxially arranged rotatable nozzle is housed, and a tubular shaft assembly is mounted on the nozzle. The tubular shaft assembly is a rotating component, and its inlet end is sealed to an external high-pressure liquid inlet assembly. The nozzle's fluid speed limiting mechanism is located within a sealed cavity and consists of an impeller, a stator tube assembly, and a turbine assembly. When the tubular nozzle shaft rotates, the impeller accelerates the fluid flow. The fluid flows through the stator tube assembly and then into the turbine assembly. The turbine assembly generates a reverse rotational force, counteracting the rotational force generated by the nozzle head assembly mounted at the end of the tubular nozzle shaft. This reduced rotational speed significantly decreases wear and heat generation of the moving parts within the nozzle assembly, while also extending the residence time of the cleaning fluid and improving the nozzle's performance.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Patent Application No. 18 / 980,590, filed December 13, 2024, entitled "High Pressure Liquid Rotary Nozzle With Fluid Brake Mechanism," and also claims the benefit of U.S. Provisional Patent Application No. 63 / 610,309, filed December 14, 2023, entitled "High Pressure Liquid Rotary Nozzle With Fluid Brake Mechanism." The entire technical contents of both applications are incorporated herein by reference. Technical Field

[0003] This invention relates to a rotary nozzle assembly for spraying high-pressure liquids, the assembly having a fluid speed limiting device. The fluid speed limiting device is driven by the rotary nozzle and functions as a rotary fluid speed limiting mechanism to prevent abnormal overspeed rotation of the nozzle. Background Technology

[0004] In the field of high-pressure rotary liquid handling equipment, operating parameters can reach 44,000 psi, 8,000 rpm, and 25 gallons / min. Rotary nozzles present numerous challenges in terms of structural design, manufacturing cost, durability, and ease of maintenance. High-pressure water jet cleaning equipment using reaction-force rotary nozzles often generates extremely high rotational speeds. In many applications such as surface treatment and cleaning, it is necessary to reduce the rotational speed of the nozzles to extend their service life and effectively improve cleaning efficiency. Existing technologies typically install a speed reduction device on the rotating shaft of the nozzle to slow down its rotation. The total length and diameter of such nozzles are usually no more than a few inches. The harsh operating conditions and extremely small size further exacerbate various technical problems. Factors such as pressure, temperature, and wear affect the durability, maintenance difficulty, and operating costs of the nozzle equipment, while also impacting the ease of use and safety of the equipment. Therefore, the industry urgently needs a speed-adjustable nozzle that is simple in structure, durable, reliable, inexpensive, and easy to maintain. Summary of the Invention

[0005] One of the objectives of this invention is to provide a durable, lightweight, and slender high-pressure rotary spray nozzle assembly that can be easily mounted on the end of a spray bar for surface treatment and / or cleaning of objects or irregularly shaped objects.

[0006] Another object of the present invention is to provide a durable rotational speed damping mechanism for a rotating nozzle in a slender, small-diameter high-pressure water jet assembly.

[0007] Another object of the present invention is to provide an improved rotational speed limiting mechanism for the rotating nozzle component of a small-diameter high-pressure spray nozzle assembly; the mechanism employs a centrifugal impeller driven by the rotating nozzle, which in turn drives a speed-limiting turbine device.

[0008] Another objective of this invention is to provide an improved rotational speed limiting mechanism for the rotating nozzle component of a small-diameter high-pressure spray nozzle assembly; this mechanism achieves braking and speed limiting effects on the nozzle by increasing the flow rate of internal lubricant through the centrifugal impeller and turbine.

[0009] Another object of the present invention is to integrate an improved rotational speed retardation mechanism for rotating nozzle components and a rotating nozzle bearing assembly into an independent sealed cavity of a small-diameter high-pressure spray nozzle assembly.

[0010] Another objective of this invention is to provide an improved rotatable nozzle assembly, wherein the housing accommodating the rotatable nozzle has an opening at one end, through which all core components such as the rotatable nozzle support bearing and the rotatable nozzle speed regulating mechanism can be removed as a whole from the common sealed cavity.

[0011] Another objective of this invention is to provide an optimized structure that allows for the replenishment or replacement of the constant viscosity lubricant used in the speed limiting mechanism inside the sealed cavity simply by temporarily removing the plug from the cavity filling port and pumping new fluid into the sealed cavity.

[0012] Another objective of the present invention is that the speed regulating mechanism is provided with a speed limiting component that generates friction. This component is immersed in a viscous liquid and, by means of viscous shearing, forms a significant resistance force on the rotating nozzle of the spray nozzle assembly.

[0013] The fluid braking mechanism described in this article can be applied to equipment commonly known in the industry as "spray gun tools." In addition, this fluid braking mechanism can be used for any hydraulic rotary tool that requires deceleration of its rotation when it lacks a mechanical braking structure.

[0014] This invention is applicable to high-pressure conditions with operating pressures ranging from approximately 2000 to 44000 psi. Therefore, the sealing structure between the relatively fixed sealing seat and the rotating input end of the rotating nozzle tube must be adapted to any selected operating pressure. Under a given pressure, the flow rate at the nozzle orifice and the eccentric structure generate a reaction force, driving the nozzle to rotate. This invention employs a mating friction-type speed limiting mechanism, which is immersed in a high-temperature resistant lubricant (such as an automatic transmission fluid) and enclosed in a protective sealed speed regulating chamber to prevent nozzle overspeed. With this structure, the nozzle speed can be stabilized at approximately 500 to 8000 rpm during spraying operations (the optimal target speed is approximately 2000 rpm). Without effective speed limit control, the uncontrolled rotating nozzle speed can reach thousands of rpm, which not only affects the spraying effect but also significantly accelerates the wear of seals, bearings, and other moving parts in the nozzle structure.

[0015] In one embodiment, radial ball bearings form a load-distributing bearing assembly arranged axially at intervals, positioned between the rotating tubular nozzle shaft and the inner cylindrical surface of the nozzle housing. The bearings provide coaxial rotational support to the tubular nozzle shaft, and when the high-pressure liquid at the rotating seal within the nozzle assembly exerts a large forward axial thrust on the shaft, the bearings restrict axial displacement of the shaft.

[0016] In one embodiment, the nozzle assembly includes a generally cylindrical housing, which serves as a relatively fixed reference structure. Inside the housing is a coaxially arranged rotatable nozzle equipped with a tubular shaft member. The tubular shaft member is a rotating component, and its input end is sealed to a high-pressure liquid inlet member at the liquid inlet end of the housing. The inner side of the liquid inlet end of the housing has an internal thread that can be screwed onto the external thread end (either a tapered pipe thread or a standard pipe thread) of a spray bar or other liquid supply component (not shown) supporting the nozzle assembly. High-pressure spray liquid is delivered to the nozzle assembly via this component.

[0017] In one embodiment, a high-pressure sealing assembly is provided between the liquid inlet component and the nozzle shaft input end, forming a flow channel for high-pressure liquid to flow to the nozzle. The sealing assembly includes a fixed annular sealing seat opposite the shaft end, supporting an annular seal element connected end-to-end. The inner diameter of the annular seal element is the same as the inner diameter of the nozzle shaft input end. A countersunk hole is machined inside the sealing seat, forming a stepped annular groove. The inner wall of the groove is a smooth cylindrical surface and coaxial with the shaft. An annular cylindrical plastic seal element and a hard, wear-resistant tungsten carbide sealing ring seat are sequentially assembled within the stepped groove. During spraying, the high-pressure liquid flows through the nozzle, and the tungsten carbide ring seat is clamped between the plastic seal element and the shaft end. The stepped groove ensures that the tungsten carbide ring seat remains coaxial with the shaft, with the front end of the ring seat extending out of the groove and forming a sealing fit with the shaft end. The outer wall of the plastic seal element fits tightly against the inner wall of the stepped groove. A flexible O-ring is also assembled in the annular groove at the axial center of the plastic seal element to further enhance the sealing effect and restrict the rotation of the plastic seal element. The pressure of the sprayed liquid presses the plastic seal against the tungsten carbide ring seat, which rotates with the shaft. When wear occurs at the end of the plastic seal that contacts the tungsten carbide ring seat, the liquid pressure pushes the plastic seal forward along the stepped groove, ensuring the continuous effectiveness of the sealing assembly at the shaft input end.

[0018] This sealing assembly can withstand the working pressure of the high-pressure spray liquid, preventing the high-pressure liquid from entering the tubular nozzle from the designated flow channel. In one embodiment, the seal is made of compression-resistant cross-linked ultra-high molecular weight polyethylene. The auxiliary sealing O-ring is preferably made of a highly elastic, wear-resistant, and high-temperature-resistant elastic material, and is fitted into a rectangular annular groove at the axial midpoint of the outer cylindrical surface of the seal; other materials or sealing structures can also be used. When the end of the seal that mates with the ring seat wears down to near the O-ring groove, the plastic seal can be removed and installed in reverse for continued use until the other end also shows the same degree of wear. This sealing assembly only requires replacement of the plastic seal with the O-ring, and the replacement cost is far lower than that of the tungsten carbide ring seat. When the spray device is working, the tungsten carbide ring seat is axially pressed and rotates synchronously with the nozzle shaft.

[0019] In one embodiment, the sealing assembly consists of three parts: a sealing seat, a plastic seal, and a tungsten carbide ring seat. These three components have a simple structure, reliable assembly, and can be replaced individually after wear, resulting in low overall operating costs and excellent sealing performance. This sealing assembly can maintain normal sealing performance even when the plastic seal has worn down to 50%.

[0020] The rotational damping mechanism of the nozzle assembly is arranged within a sealed cavity, which also houses a ball bearing assembly. The ball bearing supports the tubular rotating nozzle shaft, through which the spray liquid is delivered to the spray head. The sealed cavity isolates the spray liquid from potential leakage from the internal flow channels of the nozzle housing, protecting the bearing, rotational damping mechanism, and lubricant within the cavity. The nozzle spray head has multiple inclined spray holes. The spray liquid ejected from these holes generates a reaction force, driving the spray head and the tubular nozzle shaft to rotate relative to the nozzle housing.

[0021] The fluid velocity limiting mechanism includes an impeller assembly fixed to the shaft of a tubular rotating nozzle. When the tubular nozzle shaft rotates, it drives the impeller assembly to operate, accelerating the flow of fluid within the fluid velocity limiting mechanism.

[0022] In a preferred embodiment, the impeller device is a centrifugal impeller. A stator tube device is provided on the outside of the impeller device, forming a protective enclosure around the impeller. After the fluid flows out of the centrifugal impeller, the stator tube guides the fluid in the sealed speed regulating chamber, causing the accelerated fluid to flow through multiple flow channels between the inner and outer walls of the stator tube. The stator tube, the tubular rotating nozzle shaft, and the impeller device are arranged coaxially and fixedly mounted on the nozzle housing. A coaxial through hole is provided in the center of the stator tube, allowing the tubular nozzle shaft and the impeller device to rotate freely within the through hole. The flow channels between the inner and outer walls of the stator tube guide the fluid pushed by the impeller to multiple injection ports at the discharge end of the stator tube. The injection ports propel the accelerated fluid toward a turbine device fixed on the tubular nozzle shaft. The main body of the turbine device is cylindrical and coaxially arranged with the tubular nozzle shaft, with several turbine blades formed on the main body. The turbine blades absorb the energy of the high-speed fluid and deflect the fluid back, causing it to flow back to the impeller device through the central through hole of the stator tube. High-speed fluid impacts the turbine blades, applying a reverse torque to the tubular nozzle shaft, thereby limiting the fluid velocity on the nozzle shaft. The cross-section of each turbine blade is specially designed to generate a reverse rotational force, counteracting the rotational force generated by the spray head assembly at the end of the tubular nozzle shaft.

[0023] The sealed cavity housing the bearing and speed limiting mechanism is sealed at its front end by a removable front cover. An annular lip seal is provided between the outer surface of the shaft and the inner surface of the front cover to achieve end sealing. The rear end of the sealed cavity is sealed by an annular lip seal between the tubular shaft and the necked section of the housing. A filling port is provided on the housing, with a removable threaded plug installed inside, allowing lubricant to be injected into the sealed cavity under pressure. The lip structure of the two seals is designed such that the front seal prevents lubricant leakage, while the rear seal allows a small amount of lubricant to overflow from the lip; therefore, only the threaded plug needs to be removed to replenish or replace the lubricant in the cavity. In addition, an additional threaded interface can be added to the sealed cavity for circulating and flushing the lubricant inside.

[0024] The bearings and other internal components within the sealed bearing cavity are axially positioned using a removable front cover. After the front cover is installed, all internal components are pressed against one end of the housing, causing the components to abut against the inwardly extending stepped surface of the housing, thus maintaining the overall axial position.

[0025] During operation, the nozzle assembly moves with the support structure relative to the object or surface to be sprayed. The fluid speed limiting mechanism described in this article can stabilize the spray pattern of the spray head. Simultaneously, as the nozzle rotation speed decreases, the wear and heat generation of the moving parts inside the assembly are significantly reduced. The above description uses the high-pressure hydraulic rotary tool, commonly known in the industry as a "spray gun," as an example; this mechanism is also applicable to various fluid-type high-pressure rotary tools. Attached Figure Description

[0026] A more complete understanding of the method and apparatus of the present invention can be achieved by referring to the following detailed description in conjunction with the accompanying drawings, wherein:

[0027] Figure 1 is a front perspective view of one embodiment of the high-pressure liquid spray nozzle assembly of this device;

[0028] Figure 2a is an exploded view of the nozzle assembly;

[0029] Figure 2b is a side exploded view of the nozzle assembly;

[0030] Figure 3a is a longitudinal sectional view of the high-pressure liquid spray nozzle assembly shown in Figure 1;

[0031] Figure 3b is a longitudinal sectional view of the nozzle housing of the high-pressure liquid spray nozzle assembly shown in Figure 1, showing the internal structure of the nozzle housing;

[0032] Figures 4a and 4b are longitudinal sectional views of the spray head assembly fitted to the nozzle housing in the high-pressure liquid spray nozzle assembly shown in Figure 1.

[0033] Figure 5a is a rear perspective view of the impeller in the high-pressure liquid spray nozzle assembly shown in Figure 1.

[0034] Figure 5b is a front-view perspective view of the impeller;

[0035] Figure 5c is a top view of the impeller;

[0036] Figure 6a is a rear perspective view of the stator tube in the high-pressure liquid spray nozzle assembly shown in Figure 1.

[0037] Figure 6b is a front-view perspective view of the stator tube;

[0038] Figure 6c is a top view of the liquid inlet end of the stator tube;

[0039] Figure 6d is a top view of the liquid outlet end of the stator tube;

[0040] Figure 7a is a rear perspective view of the turbine device in the high-pressure liquid spray nozzle assembly shown in Figure 1.

[0041] Figure 7b is a front perspective view of the turbine device;

[0042] Figure 7c is a top view of the liquid inlet end of the turbine device;

[0043] Figure 7d is a top-section cross-sectional view of the inlet end of the turbine device.

[0044] In the accompanying drawings, the same reference numerals represent the same or similar components. Furthermore, the directional and limiting terms used herein, such as "top," "bottom," "first," "second," "upper side," "lower side," "height," "width," "length," "end," "side," "horizontal," and "vertical," are used only to describe the structures shown in the accompanying drawings and are intended to facilitate the explanation of the invention. Detailed Implementation

[0045] Figures 1 to 3b illustrate a high-pressure liquid nozzle device 100, which includes an elongated cylindrical nozzle housing 20. A hollow tubular nozzle shaft 60 is coaxially and rotatably mounted inside the housing. The nozzle shaft is connected to a nozzle head 90, which has several inclined spray holes 96. These inclined spray holes are in fluid communication with the coaxial flow channel 62 of the tubular nozzle shaft 60. The coaxial flow channel 62 of the tubular nozzle shaft 60 delivers high-pressure liquid to the inclined spray holes 96 of the spray head 90 at one end of the housing 20. Rotating the nozzle head 90 at the front end of the nozzle shaft 60 ejects multiple liquid jets to complete the cleaning operation. The inclined jets generate a jet reaction torque on the nozzle shaft 60, enabling the nozzle shaft to rotate autonomously. In conjunction with the shaft speed-limiting structure described below, in this illustrated embodiment, when viewed from the liquid outlet end of the nozzle assembly, its autonomous rotation direction is clockwise.

[0046] High-pressure liquid is delivered to the input end 62a of the nozzle shaft via the inlet assembly. The inlet assembly is formed by the necked inlet end of the housing 20; if the housing 20 is made of aluminum, a threaded bushing 16 can be installed inside its inlet end for connection with a standard tapered threaded connector at the end of a rigid spray bar or pipeline (not shown) which serves as the high-pressure liquid supply source for this nozzle assembly. In another embodiment, the inlet end of the housing 20 has a threaded cylindrical hole 16A, which terminates at an inwardly extending stepped surface 10A, forming an annular sealing surface. The sealing seat assembly, consisting of the snap-fit ​​housing 2, the inlet seat housing 6, the high-pressure sealing assembly 9, the limiting housing 10, and the tungsten carbide sealing seat 14, is pressed against this annular sealing surface by the liquid supply source connector. The outer surface of the sealing seat assembly is cylindrical and can be slidably assembled within the hole at the inlet end of the housing 20. The inlet housing 6 has a conical high-pressure liquid inlet that gradually narrows forward to form a small-diameter cylindrical throttling orifice. A smooth, stepped annular countersunk hole is machined in front of the throttling orifice, completely enclosing the axially sliding high-pressure sealing assembly 9. The high-pressure sealing assembly 9 abuts against a hard, wear-resistant annular tungsten carbide sealing seat 14, which is partially embedded within the countersunk hole of the limiting housing 10.

[0047] When the standard tapered threaded connector of the high-pressure liquid supply end is fixed to the liquid inlet end of the housing 20, a sealing connection is formed at the tapered inlet of the sealing seat assembly, firmly pressing the sealing seat assembly against the stepped surface at the end of the liquid inlet end hole of the housing 20. The sealing seat assembly has a coaxial stepped countersunk hole structure with a smooth inner wall. The annular cylindrical deformable high-pressure sealing assembly 9 and the annular hard tungsten carbide sealing seat 14 on the limiting housing 10 are connected end to end and arranged coaxially. The pressure of the high-pressure liquid acts solely on the high-pressure sealing assembly 9 and the limiting housing 10, pushing the tungsten carbide sealing seat tightly against the input end 62a of the tubular nozzle shaft. The outer edge of the sealing seat end face of the limiting housing 10 is chamfered, and the contact area between this end face and the tubular nozzle shaft 60 is smaller than the contact area between its other side and the liquid inlet housing 6. During equipment operation, the high-pressure liquid in the inlet channel creates a pressure difference on both sides of the sealing seat, ensuring that the sealing seat 18 of the limiting housing 10 is always pressed against the input end 62a of the tubular nozzle shaft. The high-pressure sealing assembly 9 is made of high-strength, wear-resistant, deformable, and compression-resistant rigid engineering plastic.

[0048] After the tapered threaded connector of the high-pressure liquid supply end is removed from the liquid inlet end of the housing 20, the sealing seat assembly, which consists of the snap-fit ​​housing 2, the liquid inlet seat housing 6, the high-pressure sealing assembly 9, the limiting housing 10, and the tungsten carbide sealing seat 14, can be directly pulled out from the liquid inlet end of the housing 20 for inspection, maintenance, or replacement, without the need to disassemble other parts of the nozzle device.

[0049] The sealing seat assembly, consisting of a snap-fit ​​housing 2, an inlet seat housing 6, a high-pressure sealing component 9, a limiting housing 10, and a tungsten carbide sealing seat 14, forms a high-pressure liquid sealing structure inside the housing 20. This structure confines the high-pressure liquid within a flow channel 62 between the inlet port of the housing 20 and the input end 62a of the tubular nozzle shaft. This flow channel is isolated from the sealing cavity between the tubular nozzle shaft 60 and the housing 20. If high-pressure liquid leaks from the outside of the sealing seat assembly, it can be discharged to the outside of the nozzle assembly through a strip-shaped drain channel 18 on the housing 20. The input end 62a of the tubular nozzle shaft 60 has a reduced diameter section that extends rearward through a small hole in the transverse partition of the housing 20 and into the cavity connected to the drain hole 18. The tungsten carbide sealing seat 14 forms a sealing fit with the nozzle shaft input end 62a at this location.

[0050] The inner cylindrical surface of the nozzle housing 20 forms a sealed cavity, and the fluid speed limiting mechanism is arranged inside this sealed cavity. The front end of the sealed cavity, which houses the bearing and the fluid speed limiting mechanism, is sealed by a removable front end cover 80. An annular rear end lip seal 72 is provided between the outer surface of the nozzle shaft 60 and the inner surface of the front end cover 80. Radial ball bearings 24 and axial ball bearings (angular contact bearings or radial ball bearings) 70 are arranged inside the sealed cavity to provide rotational support for the tubular nozzle shaft 60. The fluid speed limiting mechanism and lubrication structure, which are described in detail below, are also provided inside the cavity. The two ends of the sealed cavity are defined by a front shaft seal 72 and a rear shaft seal 22, respectively. The front shaft seal 72 is located between the thrust bearing 70 and the front end cover 80, and the rear shaft seal 22 is located between the rear end bearing 24 and the inner stepped surface 22A of the housing 20.

[0051] Lip seals 22 and 72, located at both ends of the sealing cavity between the rotating shaft and the housing 20, have their sealing lips facing inwards towards the nozzle device. Lubricating fluid can be added to the cavity using a conventional syringe-like instrument through the filling hole sealed by the threaded plug 27. After replenishing or replacing the lubricating fluid, the threaded plug is tightened again to seal the cavity. Additionally, the lubricating fluid within the sealing cavity can be circulated and flushed using the threaded plug interface 27A and the spare interface 28A. The threaded plug 27 is located near the rear end of the housing 20, at the reduced diameter section where the housing transitions to the inlet end. The rear shaft seal 22 is designed to allow excess lubricating fluid to flow into the drain channel 18 of the housing 20 and ultimately exit outside the nozzle device 100. With continuous injection of clean lubricating fluid, when clear liquid flows out of the housing drain hole 18, it indicates that the deteriorated or contaminated lubricating fluid in the cavity has been completely replaced.

[0052] The front end of the tubular nozzle shaft 60 is rotatably supported by a radial thrust ball bearing 70. An annular front end cap 80 is fitted to the front end of the nozzle housing 20, and the front end cap is threaded onto the inner side of the front end of the housing. The rear end of the tubular nozzle shaft 60 is supported by a radial ball bearing 24 located between the shaft and the housing 20. The outer ring of the thrust bearing 70 is pressed against the front end cap 80 to achieve axial positioning. After the equipment is assembled, the inner ring of the thrust bearing 70 is clamped between the relative steps of the tubular nozzle shaft 60, thereby fixing the axial position of the tubular nozzle shaft 60.

[0053] It is necessary to ensure that the torque generated by the jet stream emitted from the inclined spray holes 96 of the spray head assembly 90 is within the allowable operating range of the equipment. The preferred operating torque range for the equipment is 4 to 30 in.lbs, and the general operating torque should not exceed 35 in.lbs. Setting the upper limit to 35 in.lbs allows for a larger tolerance margin in the overall operating parameters of the equipment.

[0054] Based on the pump specifications and assembly method, the jet reaction force and nozzle eccentric structure are designed to generate a torque of 4 to 30 in.lbs. Insufficient torque will lead to unstable nozzle speed, or even failure to start rotation; excessive torque will exceed the equipment's speed control capability, causing heat buildup in internal parts, increased temperature rise, and rapid wear of seals. Simultaneously, abnormally high nozzle speed will affect the jet cleaning effect. The normal operating torque of the equipment should not exceed 35 in.lbs.

[0055] The flow coefficient of this equipment is 0.38 Cv. At a flow rate of 9 gallons / minute, the internal pressure loss is approximately 560 psi; at a flow rate of 12 gallons / minute, the pressure loss is approximately 997 psi.

[0056] The outer wall of the high-pressure sealing assembly 9 is tightly fitted to the inner wall of the stepped countersunk hole of the inlet housing 6. An O-ring seal is installed in the annular groove at the axial center of the inlet housing 6. This seal further enhances the sealing performance between the plastic seal and the stepped countersunk hole wall, and also restricts the rotation of the high-pressure sealing assembly 9. The pressure of the sprayed liquid pushes the high-pressure sealing assembly 9 forward, making it tightly fitted with the tungsten carbide sealing seat 14. The high-pressure sealing assembly 9 rotates together with the input end 62a of the tubular nozzle shaft, and the tungsten carbide sealing seat 14 also rotates synchronously with the nozzle shaft. When wear occurs at the end face of the high-pressure sealing assembly 9 in contact with the tungsten carbide sealing seat 14, the liquid pressure will push the high-pressure sealing assembly 9 to continue moving forward along the cylindrical countersunk hole of the inlet housing 6, always ensuring the sealing effect of the input end 62a of the tubular nozzle shaft. The O-ring seal inside the inlet housing 6 effectively prevents high-pressure liquid from leaking from the outside of the high-pressure sealing assembly 9.

[0057] The speed limiting structure for controlling the rotational speed of the tubular nozzle shaft 60 is a fluid speed limiting mechanism arranged within the sealed cavity of the nozzle housing 20. This fluid speed limiting mechanism consists of an axial-flow centrifugal impeller 50, a stator tube assembly 40, and a turbine disk 30, all three being coaxially arranged with the tubular nozzle shaft 60. The centrifugal impeller 50 and turbine disk 30 are fixed to the tubular nozzle shaft 60, while the stator tube assembly 40 is fixedly mounted on the inner cylindrical surface of the nozzle housing 20. That is, the centrifugal impeller 50 and turbine disk 30 rotate together with the tubular nozzle shaft 60, while the stator tube assembly 40 remains stationary relative to the nozzle shaft. When the tubular nozzle shaft 60 drives the centrifugal impeller 50 to rotate, the impeller accelerates the flow of fluid within the sealed cavity. The closed end face 52 of the impeller 50 (see Figure 5b) is adjacent to the main step surface 66 of the tubular nozzle shaft 60. An annular groove 68 is machined on the tubular nozzle shaft 60, and a retaining ring 65 is installed in the groove to fix the axial position of the impeller assembly 50 relative to the nozzle shaft. After the turbine assembly 30 is assembled in place in the sealing cavity of the nozzle housing 20, the retaining ring 65 is adjacent to the front flange 38 of the center hole 34 of the turbine assembly 30 (see Figure 7b), and the two do not contact each other.

[0058] The impeller 50 is covered and shielded by the stator tube assembly 40. After the fluid flows out of the centrifugal impeller 50, the stator tube assembly 40 guides the fluid, causing the accelerated fluid to flow through multiple flow channels 47 formed between the inner wall 45 and the outer wall 41 of the stator tube assembly 40. Each flow channel 47 between the inner and outer walls of the stator tube assembly directs the fluid to the respective injection ports at the liquid outlet end of the stator tube assembly.

[0059] The injection port 48 (see Figures 6a and 6b) directs the accelerated fluid toward the turbine disk assembly 30 fixed to the tubular nozzle shaft 60. The turbine disk 30 is cylindrical in shape and coaxially fixed to the tubular nozzle shaft 60, with several turbine blades 32 mounted on it. The turbine blades absorb the energy of the high-speed fluid and deflect the fluid back, allowing it to flow back to the impeller assembly 50 through the central hole 46 of the stator tube assembly 40. The high-speed fluid impacts the turbine blades 32, applying a reverse torque to the tubular nozzle shaft 60, thereby limiting the fluid speed on the nozzle shaft. The cross-section of each turbine blade 32 is specially designed to generate a reverse rotational force, counteracting the rotational force generated by the spray head assembly 90 at the end of the tubular nozzle shaft 60. Depending on the actual operating conditions, turbine blades 32 with different shapes can be designed to give the turbine assembly different speed and torque characteristics. Overall, the fluid speed limiting mechanism of the present invention has a speed limiting effect that increases with the increase of the rotational speed of the spray head assembly 90, so that the nozzle maintains a relatively stable rotational speed within the range of input torque variation.

[0060] Referring to Figures 5a to 5c, the illustration shows one embodiment of the centrifugal impeller 50 of the present invention. The cross-section of the central hole 54 of the centrifugal impeller 50 engages with the outer cross-section of the tubular nozzle shaft 60, causing the centrifugal impeller 50 and the tubular nozzle shaft 60 to rotate synchronously. The longitudinal cross-section of the impeller body 51 extends outward in an arc shape from the smallest circumference 51A near the center of rotation to the largest circumference 51B. The impeller 50 is provided with several blades for propelling the fluid to accelerate outward from the center of rotation. The blades can be arranged along the entire length of the impeller body 51 or only in a portion of the body. As shown in Figure 5a, the blades include several main blades 56 and several secondary blades 58. The main blades 56 extend along the entire length of the impeller body 51, while the secondary blades 58 are only arranged in the lower half of the impeller body near the largest circumference 51B. In the figures, the blades are planar structures and perpendicular to the axis of rotation; the present invention can also employ various blade structures, such as arc shapes.

[0061] Referring to Figures 6a to 6d, the illustrations show one embodiment of the stator tube device 40 of the present invention. The stator tube device 40 is an annular component with two independent flow channels inside, which can guide the fluid in the sealed speed regulating chamber to flow in the opposite direction. The annular outer wall 41 of the stator tube device 40 covers the outside of the centrifugal impeller 50, collects the high-speed fluid flowing out from the maximum circumference 51B of the impeller, and guides the fluid into multiple flow channels between the outer wall 41 and the inner wall 45. The cross-sectional area of ​​the flow channel 47 preferably gradually narrows along the fluid flow direction, so that the diameter of the nozzle 48 at the liquid outlet 43 of the stator tube device 40 is much smaller than that of the flow channel inlet 47a. The narrowing of the flow channel can increase the pressure and velocity of the fluid at the nozzle 48, and the nozzle 48 can be designed to spray fluid in a direction at an acute angle to the axis of rotation.

[0062] The stator tube assembly 40 is coaxially arranged with the rotatable tubular nozzle shaft 60 and impeller assembly 50, and fixed to the nozzle housing 20. In the illustrated embodiment, the stator tube assembly 40 has multiple axial protrusions 44 on its outer side, which engage with the corresponding axial grooves 26 (see Figure 3b) on the inner surface of the nozzle housing 20. A retaining ring 67 is fitted in the annular groove 69 on the inner surface of the nozzle housing 20 to limit the axial position of the stator tube assembly 40 and prevent it from axially shifting under the thrust of the fluid from the injection port 48.

[0063] The stator tube assembly 40 is provided with a coaxial central hole 46, within which the tubular nozzle shaft 60 and the impeller assembly 50 can rotate freely. Each flow channel between the inner and outer walls of the stator tube assembly can guide the fluid pushed by the impeller to the corresponding injection port 48 at the stator tube outlet end 43, and the injection port shoots the fluid toward the turbine assembly 30 fixed on the tubular nozzle shaft 60.

[0064] Referring to Figures 7a to 7c, the turbine assembly 30 is generally annular and coaxially fixed with the tubular nozzle shaft 60, and is equipped with several turbine blades 32. The turbine blades absorb the energy of the high-speed fluid, guide and deflect the fluid, causing it to flow back to the impeller assembly 50 through the central hole 46 of the stator tube assembly 40. The high-speed fluid impacts the turbine blades, applying a reverse torque to the tubular nozzle shaft 60, thus achieving the fluid speed limiting function. The cross-sectional structure of a single turbine blade can generate a reverse rotational force, counteracting the rotational torque generated by the spray head assembly 90 at the end of the tubular nozzle shaft 60.

[0065] The cross-section of the central hole 34 of the turbine assembly 30 engages with the outer cross-section of the tubular nozzle shaft 60, ensuring synchronous rotation. A stepped surface 35 (see Figures 7c and 7d) is provided within the central hole 34 of the turbine assembly 30, which fits against the corresponding stepped surface 63 on the tubular nozzle shaft 60. Referring to Figure 3a, the wave spring 64 generates an axial force, causing the rear end face 31 of the turbine assembly 30 to partially abut against the step of the shaft bearing 24, thereby fixing the axial position of the turbine assembly 30. Referring to Figures 7a to 7c, the turbine assembly 30 also has a pressure relief hole 36, through which some of the fluid impacting the turbine blades can flow to the rear end face 31 of the turbine assembly, balancing the fluid pressure at the front and rear ends of the turbine assembly. This also provides buffering and lubrication for the turbine assembly 30, the rear end bearing 24, and the inner cavity 30A of the nozzle housing 20 (see Figure 3b).

[0066] As shown in Figure 7d, the cross-section of the single turbine blade 32 is a U-shaped structure. This structure can guide the fluid to flow from the outer circumference of the turbine device 30 to the inner side, fully absorb the energy of the high-speed fluid, and guide the fluid back to the impeller device 50 through the central hole 46 of the stator tube device 40.

[0067] The lubricant used in the bearings and fluid speed limiting mechanism is preferably a conventional automatic transmission fluid. The lubricant is injected into the sealed cavity through the filling port 27A on the nozzle housing 20. Under normal circumstances, the filling port is sealed by the threaded plug 27 to prevent lubricant leakage. The lubricant in the sealed cavity is continuously agitated as the equipment operates. The heat generated by the rotating fluid speed limiting mechanism and bearing is dissipated through the contact parts by heat conduction, and is also transferred to components such as the nozzle housing 20 and the tubular nozzle shaft 60 by means of the lubricant. During spraying operations, the high-pressure spray fluid flows through the tubular nozzle shaft, which can further remove the heat from the shaft.

[0068] Conventional automatic transmission fluid (ATF) has a kinematic viscosity of approximately 7.24 centistokes at 100°C and approximately 33.3 centistokes at 40°C, with a temperature limit of approximately 240°F and a viscosity index greater than 190, exhibiting superior shear stability compared to ordinary engine oil. Synthetic ATF blends have viscosities of 7.5 centistokes (100°C) and 34 centistokes (40°C), with a temperature limit of 270°F and a viscosity index of 198; fully synthetic ATFs can withstand temperatures up to 300°F. The lubricant used in this invention needs to maintain viscosity stability during long-term equipment operation; silicone-based lubricants and other lubricating media with excellent viscosity characteristics and heat resistance can also be used.

[0069] To extend equipment lifespan while using low-cost structural materials, it is essential to maintain a lubricating film on the surface of speed-limiting components immersed in lubricating fluid to prevent dry friction at component contact surfaces. Effective speed limiting is achieved through the viscous shearing action of the lubricating fluid, while simultaneously reducing wear on moving parts. This lubricating film is particularly critical under continuous equipment operation; however, short-term dry friction may be permissible for short-term or intermittent operation, or due to environmental constraints.

[0070] Unless otherwise stated, in this preferred embodiment, the metal components of each part are preferably made of high-strength, corrosion-resistant materials such as stainless steel. In other embodiments designed to meet the requirements of weight reduction and heat dissipation, the nozzle housing 20 may be made of aluminum, and the impeller assembly 50, turbine assembly 30, and stator tube assembly 40 may be made of 3D-printed plastic or metal.

[0071] Based on the above embodiments, those skilled in the art can conceive of various modified structures within the scope of this invention. The above description is merely for illustrating the technical features of this invention, and the scope of protection of this invention is defined by the appended claims. Although this invention has been described in conjunction with preferred embodiments, various adjustments and modifications can be made without departing from the spirit and scope of this invention. The terminology used herein is for descriptive purposes only and does not constitute limitation; this invention covers all equivalent alternative structures falling within its spirit and scope.

Claims

1. A nozzle assembly for spraying high-pressure liquid onto an object, comprising: A hollow cylindrical shell, the shell having a cylindrical inner hole and a front end cover component; A tubular shaft, which can rotate coaxially within a housing and has a liquid inlet; the outlet end of the tubular shaft extends through the front end cover member and is connected to a spray nozzle head, wherein the spray nozzle head is used to drive the tubular shaft to rotate. The bearing mechanism is arranged axially between the tubular shaft and the inner cylindrical surface of the housing. It is used to provide coaxial rotational support for the tubular shaft and to limit the axial movement of the tubular shaft when the tubular bearing is subjected to a large axial force during the spraying operation. A device defining a sealing cavity between the housing and the tubular shaft for sealing the bearing mechanism and the viscous fluid lubricant; A connection structure for connecting a high-pressure liquid source to the input end of a nozzle assembly, wherein the connection structure is in a sealed fit with the input end of a tubular shaft; A speed limiting mechanism, coaxially arranged with the tubular shaft within the sealed cavity, is used to apply resistance to the tubular shaft to prevent its rotational speed from exceeding a set range. The speed limiting mechanism includes: An impeller assembly connected to a tubular shaft, wherein the impeller assembly is used to accelerate the flow of a viscous fluid lubricant within a sealed cavity; A stator tube assembly is attached to the cylindrical inner hole of the nozzle housing, wherein the stator tube assembly guides the accelerating fluid output from the impeller assembly to a plurality of injection ports located at its discharge end. A turbine disk connected to a tubular shaft and having multiple turbine blades, wherein the turbine blades receive an accelerated viscous fluid lubricant flowing from the injection port and guide the fluid back, causing it to flow back to the impeller assembly through the central hole of the stator tube assembly; wherein the turbine blades absorb the energy of the accelerated fluid and apply a reverse torque to the tubular shaft.

2. The nozzle assembly of claim 1, wherein the access structure includes a sealing assembly that forms a high-pressure liquid sealed flow channel between the high-pressure liquid source and the liquid inlet end of the tubular shaft.

3. The nozzle assembly according to claim 1, wherein the front end cap member is threadedly mounted on the housing, the front end cap member having a central hole that seals with the surface of the tubular shaft, wherein a sealing cavity is closed at the output end of the nozzle assembly.

4. The nozzle assembly (100) according to claim 1, wherein the impeller device is a centrifugal impeller.

5. The nozzle assembly according to claim 1, wherein the stator tube device guides the accelerating fluid output by the impeller device to each injection port through multiple flow channels formed between its inner and outer tube walls.

6. The nozzle assembly of claim 1, wherein the injection port injects a viscous fluid lubricant at an acute angle to the axis of rotation.

7. The nozzle assembly of claim 1, wherein the turbine assembly has a pressure relief port, and a portion of the viscous fluid lubricant impacting the turbine blades can flow through the turbine body to the rear side of the turbine assembly, thereby providing cushioning and lubrication for the turbine assembly and bearing mechanism.

8. The nozzle assembly of claim 1, wherein each of the turbine blades has a U-shaped cross section.

9. The nozzle assembly according to claim 1, wherein the outer surface of the stator tube device has a plurality of axial protrusions, the axial protrusions engaging with corresponding axial grooves provided on the inner wall of the nozzle housing.

10. The nozzle assembly of claim 1, wherein the stator tube assembly is disposed outside the impeller assembly.

11. The nozzle assembly of claim 1, wherein the hollow cylindrical housing has an access port through which a sealed cavity can be accessed to maintain a viscous fluid lubricant.

12. The nozzle assembly of claim 1, wherein the spray nozzle head has one or more inclined discharge holes, the inclined discharge holes being in fluid communication with the output end of the tubular shaft.

13. The nozzle assembly of claim 1, wherein the impeller device has a plurality of main blades extending along the entire length of the impeller body.

14. The nozzle assembly of claim 13, wherein the impeller device further comprises a plurality of secondary blades arranged in the lower region of the impeller body.

15. The nozzle assembly according to claim 14, wherein the main blades and auxiliary blades of the impeller device are arranged along the axis of rotation.

16. The nozzle assembly of claim 14, wherein the main blades and auxiliary blades of the impeller device are curved relative to the axis of rotation.

17. The nozzle assembly of claim 1, wherein the turbine blades are arranged perpendicular to the axis of rotation.

18. The nozzle assembly of claim 1, wherein the turbine blades are arranged at an acute angle relative to the axis of rotation.

19. The nozzle assembly of claim 1, wherein the viscous fluid lubricant is an automatic transmission fluid or a silicone-based lubricant.

20. The nozzle assembly of claim 1, wherein the means for defining a sealing cavity between the housing and the tubular shaft for sealing the bearing mechanism and the viscous fluid lubricant includes a rear shaft seal disposed near the rear bearing and a front shaft seal mounted on the front cover member.

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