Self-stabilizing floating ball device and blow molding tool

Abstract

A self-stabilizing floating sphere device comprising an upper casing (1) and a lower casing (2) connected to each other, characterized in that the interior of the upper casing (1) forms a sealed main buoyancy chamber, the outer surface of which is dark in color; wherein the interior of the lower casing (2) forms an open ballast tank, the side walls and / or bottom of which are provided with several inlet openings (3) through which water can enter, and the outer surface of which is light in color; wherein the upper casing (1) is flat-spherical and hollow, provides the main buoyancy and is separate from the lower casing; wherein the design of the ballast tank enables the floating sphere device to automatically take on ballast water when deployed on the water surface in order to lower the center of gravity, achieve self-stability and at the same time ensure resistance to wind, waves and tipping.

Description

TECHNICAL AREA The present invention relates to the field of technologies for saving and protecting water resources, in particular a self-stabilizing floating ball device, a blow molding tool, a manufacturing method and a method for reducing evaporation in reservoirs. STATE OF THE ART Undesired evaporation from reservoirs, lakes, and other water storage facilities is one of the main causes of water loss. To reduce such evaporation losses, physical covering to shield the water surface from sunlight and air circulation is a direct and effective method. The use of a large number of floating spheres on the water surface to form a covering layer is particularly noteworthy due to its relatively controllable cost and good adaptability. Currently, the following types of solutions exist in this technical field: The first type comprises conventional hollow, sealed floating spheres. These floating spheres are generally fully sealed, hollow plastic spheres whose position is stabilized by counterweights attached to the bottom. For example, Chinese patent CN105905247A discloses a hollow floating sphere for preventing evaporation from the water surface of reservoirs in arid plains. It is made of polyolefin material and has a light gray surface to reduce heat absorption. However, this design has significant drawbacks: The center of gravity remains near or above the geometric center of the sphere, so the spheres can easily tip over, slip, or collide with each other under the influence of wind and waves.This leads to gaps in the covering layer on the water surface and a drastic reduction in evaporation resistance. At the same time, the one-piece sealing structure requires complex manufacturing processes and high costs; moreover, after a failure, it is difficult to repair the water ingress, so these are essentially disposable products. The second type comprises covering systems with floating cakes or floating panels. These systems cover the water surface with large, continuous or composite floating panels, sometimes combined with photovoltaic modules (photovoltaic evaporation suppression). While they offer good coverage continuity, they adapt poorly to water level fluctuations, can be easily damaged in strong winds and high waves, are extremely cumbersome to install, remove, and maintain, and have very high initial and maintenance costs, making large-scale deployment in large reservoirs difficult. The third type comprises floating sphere structures with specific functions. Existing technology includes some floating spheres designed to address other engineering problems, such as floating sphere switches for protecting water pumps from running dry (e.g., CN222686893U) or floating sphere structures for floating foundations at sea (e.g., CN223148653U). The design objective of these floating spheres is not large-scale evaporation suppression at the water surface; their design either fails to consider group stability and interaction after large-scale deployment or is too complex and costly to meet the core requirements of evaporation suppression in reservoirs—low cost, high reliability, and ease of maintenance. Furthermore, the existing technology also exhibits significant weaknesses in mass production, as well as in the operation and maintenance of the floating spheres. Conventional blow-molded products require tempering to eliminate internal stresses. This process typically takes place in fixed workshops, is energy-intensive and time-consuming, and necessitates a second transport from the factory to the reservoir, increasing the carbon footprint and costs. Operational monitoring currently relies primarily on manual inspections to detect defective floating spheres (e.g., due to water ingress, sinking, or tipping). This is inefficient, costly, and hinders comprehensive real-time monitoring of large bodies of water. In summary, existing floating sphere devices for evaporation suppression on the water surface utilize closed units that float and cover the water's surface to achieve this effect. However, these devices do not optimally utilize the properties of water and its interaction with the floating spheres to achieve maximum effectiveness. Common problems include insufficient stability in wind and waves, low efficiency in mass production and deployment, high operating and maintenance costs throughout the entire life cycle, and the lack of intelligent monitoring methods. CONTENT OF THE PRESENT INVENTION The present invention provides a self-stabilizing floating ball device, a blow molding tool, a manufacturing method, and a method for suppressing evaporation in reservoirs to solve the aforementioned problems. In a first aspect, the present invention provides a self-stabilizing floating sphere device comprising an upper casing and a lower casing connected to each other; wherein the interior of the upper casing forms a sealed main buoyancy chamber, the outer surface of which is dark in color; wherein the upper casing is flat-spherical and hollow, provides the main buoyancy, and is separate from the lower casing; wherein the interior of the lower casing forms an open ballast tank, the side walls and / or bottom of which are provided with several inlet openings through which water can enter, and the outer surface of which is light in color; the arrangement of the ballast tank enables the floating sphere device to automatically take on ballast water when deployed on the water surface in order to lower the center of gravity, achieve self-stability, and simultaneously ensure resistance to wind, waves, and tipping. When the device is deployed on the surface of a reservoir, its initial position, influenced by its own weight and buoyancy, is typically such that the lower casing partially submerges. At this point, the surrounding water flows naturally through the inlet openings into the ballast tank of the lower casing. With the continuous inflow of water, the volume of water in the ballast tank gradually increases, significantly lowering the center of gravity of the entire floating sphere device. This process occurs automatically and requires no external intervention. Finally, the entire device stabilizes in a state of equilibrium: most of the buoyancy is provided by the sealed main buoyancy chamber in the upper casing, while most of the mass (weight) is provided by the water in the ballast tank of the lower casing.This configuration, characterized by "light on top and heavy on the bottom" and "buoyancy on top and pressure on the bottom," causes the device's overall center of gravity to lie far below its center of buoyancy, creating a mechanical effect similar to that of a "roly-poly toy," i.e., a self-stabilizing effect. In the event of wind or wave disturbances, the device generates a counter-moment, allowing it to resist tilting and tipping, and to quickly return to an upright position once the disturbance ceases. This enables a water surface covering consisting of thousands of such floating spheres to maintain a uniform and dense distribution over the long term, effectively shielding the water surface, reducing evaporation pathways, and thus achieving permanent and efficient evaporation suppression. By utilizing the surrounding water as ballast in open ballast tanks, automated and cost-effective weight balancing is achieved.By adding water as ballast, the center of gravity is physically lowered, fundamentally solving the technical problem of the high center of gravity and the susceptibility to tipping inherent in conventional sealed float spheres, and achieving excellent dynamic stability. The design with differently colored upper and lower housings not only serves functional purposes but also lays the foundation for future visual monitoring. In an optional embodiment, the upper housing and the lower housing are connected by locking lug components evenly distributed in the circumferential direction, wherein the locking lug component comprises a locking hook arranged at the edge of the upper housing and a locking base arranged at the edge of the lower housing, which lock into each other by vertical downward pressure. In an optional embodiment, the mold closure line between the upper housing and the lower housing has a locally reinforced structure formed by the blow molding tool, the thickness of which is greater than that of the middle part of the housing, wherein the mold closure line of the upper housing is located at the position of the equatorial plane of the float ball. In an optional embodiment, the inlet opening is a through-hole formed during the blow molding of the lower housing by synchronous piercing through a mandrel sliding axis mechanism integrated into the mold, and has a diameter of 3 mm to 5 mm. In an optional embodiment, the light color is white or light grey, the dark color is black or dark grey, with the color contrast between the upper and lower housing making it possible to monitor the position of the float ball on the water surface using image recognition technology. In a second aspect, the present invention provides a blow molding tool for manufacturing the self-stabilizing floating ball device, wherein the mold closing edge of the blow molding tool has an offset cutting edge with a concave upper and a convex lower side and uses a squeeze cutting technique; wherein the blow molding tool further comprises: a mandrel sliding axis opening mechanism comprising a mandrel-shaped structure with a sliding axis integrated into the mold of the lower housing; a temperature control system for separate temperature control in the area of ​​the mold closing line. In a third aspect, the present invention further provides a method for manufacturing the self-stabilizing floating ball device, comprising the following steps: forming the upper and lower housings each by means of a blow molding process; assembling the formed upper and lower housings by means of a connecting mechanism; placing the assembled floating ball device in a movable tempering box and performing a tempering treatment according to a predetermined temperature curve to eliminate internal stresses. In an optional embodiment, the tempering treatment is carried out in the step of placing the assembled floating ball device in a movable tempering box and performing a tempering treatment according to a predetermined temperature curve to eliminate the internal stresses during the transport of the floating ball device to the deployment site at the reservoir in the tempering box mounted on the transport vehicle, thereby achieving an integration of production, tempering and logistics. In a fourth aspect, the present invention further provides a method for suppressing evaporation in reservoirs, comprising the following steps: deploying the floating ball device on the water surface of the reservoir, ensuring that the lower housing is immersed in the water first so that the ballast tank automatically fills with water via the inlet openings; capturing images of the floating ball array on the water surface by means of an image recognition-based monitoring system and automatically identifying and locating defective floating balls that have turned over or tilted, based on the visible ratio between the dark upper housing and the light lower housing in the images. In an optional embodiment, the method, after identifying a defective floating sphere, further includes: dispatching an unmanned vessel with a visual tracking function to the location of the defective floating sphere in order to automatically recover it. In an optional embodiment, the floating ball devices are deployed by means of a deployment vessel or vehicle with an automatic deployment function, wherein the deployment device controls the distance between adjacent floating balls according to a preset deployment density so that they are close together. BRIEF DESCRIPTION OF THE DRAWING To more clearly explain the technical solution in the specific embodiments of the present invention or in relation to the prior art, the drawings to be used in the explanation of the specific embodiments or for the prior art are briefly introduced below. Obviously, the drawings described below show only some embodiments of the present invention. The person skilled in the art in this field can, provided no creative work is done, derive other drawings from these drawings. Fig. 1 shows a schematic diagram of the structure of a self-stabilizing floating ball device in an embodiment of the present invention. Fig. 2 shows a schematic diagram of the structure of a lower housing in a self-stabilizing floating ball device in an embodiment of the present invention.Figure 3 shows a schematic diagram of a lower housing after water has penetrated a self-stabilizing floating ball device in an embodiment of the present invention. Reference symbol list 1 Upper housing 2 Lower housing 3 Inlet opening DETAILED DESCRIPTION In conjunction with the accompanying drawings in the exemplary embodiments of the present invention, the technical solution in these embodiments is explained clearly and completely below, so that the objective, the technical solutions, and the advantages of the present invention become clearer. Obviously, the described exemplary embodiments do not represent all embodiments, but only a subset of them. All other embodiments that a person skilled in the art in this field could obtain from the exemplary embodiments in the present invention without any creative work should be considered to be within the scope of protection of the present invention. Undesired evaporation from reservoirs, lakes, and other water storage facilities is one of the main causes of water loss. To reduce such evaporation losses, physical covering to shield the water surface from sunlight and air circulation is a direct and effective method. The use of a large number of floating spheres on the water surface to form a covering layer is particularly noteworthy due to its relatively controllable cost and good adaptability. Currently, the following types of solutions exist in this technical field: The first type comprises conventional hollow, sealed floating spheres. These floating spheres are generally fully sealed, hollow plastic spheres whose position is stabilized by counterweights attached to the bottom. For example, existing technology reveals a hollow floating sphere for preventing evaporation from the water surface of reservoirs in arid plains. This sphere is made of polyolefin material and has a light gray surface to reduce heat absorption. However, this design has significant drawbacks: The center of gravity remains near or above the geometric center of the sphere, meaning that the spheres can easily tip over, shift, or collide with each other under the influence of wind and waves.This leads to gaps in the covering layer on the water surface and a drastic reduction in evaporation resistance. At the same time, the one-piece sealing structure requires complex manufacturing processes and high costs; moreover, after a failure, it is difficult to repair the water ingress, so these are essentially disposable products. The second type comprises covering systems with floating cakes or floating panels. These systems cover the water surface with large, continuous or composite floating panels, sometimes combined with photovoltaic modules (photovoltaic evaporation suppression). While they offer good coverage continuity, they adapt poorly to water level fluctuations, can be easily damaged in strong winds and high waves, are extremely cumbersome to install, remove, and maintain, and have very high initial and maintenance costs, making large-scale deployment in large reservoirs difficult. The third type comprises floating sphere structures with specific functions. Existing technology includes some floating spheres designed to solve other engineering problems, such as floating sphere switches to protect water pumps from running dry or floating sphere structures for floating foundations at sea. The design objective of these floating spheres is not large-scale evaporation suppression on the water surface; their design either fails to consider group stability and interaction after large-scale deployment or is too complex and expensive to meet the core requirements of evaporation suppression in reservoirs—low cost, high reliability, and ease of maintenance. Furthermore, the existing technology also exhibits significant weaknesses in mass production, as well as in the operation and maintenance of the floating spheres. Conventional blow-molded products require tempering to eliminate internal stresses. This process typically takes place in fixed workshops, is energy-intensive and time-consuming, and necessitates a second transport from the factory to the reservoir, increasing the carbon footprint and costs. Operational monitoring currently relies primarily on manual inspections to detect defective floating spheres (e.g., due to water ingress, sinking, or tipping). This is inefficient, costly, and hinders comprehensive real-time monitoring of large bodies of water. In summary, the floating ball devices known in existing technology for suppressing evaporation on the water surface generally have common problems such as insufficient stability in wind and waves, low efficiency in mass production and use, high operating and maintenance costs over the entire life cycle, and the lack of intelligent monitoring methods. In connection with Fig. 1, Fig. 2 to Fig. 3, the exemplary embodiments of the present invention are explained in more detail below. In one embodiment of the present invention, a self-stabilizing floating ball device is provided, comprising an upper housing 1 and a lower housing 2 connected to each other, wherein the interior of the upper housing 1 forms a sealed main buoyancy chamber, the outer surface of which is dark in color; wherein the interior of the lower housing 2 forms an open ballast tank, the side walls and / or bottom of which are provided with several inlet openings 3 through which water can enter, and the outer surface of which is light in color; the arrangement of the ballast tank enables the floating ball device to automatically take on ballast water when deployed on the water surface in order to lower the center of gravity and achieve self-stability. The upper casing 1 is shaped like an oblate sphere or a hemispherical dome; its interior forms a completely sealed cavity that constitutes the main buoyancy chamber, providing the primary buoyancy. The main buoyancy chamber is filled with air or another light gas to ensure that the overall density of the device is less than that of water. The outer surface of the upper casing 1 is dark-colored, for example, black, dark gray, or dark green. Its main function is to reflect solar radiation, reducing the heat absorption of the device itself and thereby indirectly reducing heat transfer to the water below. The lower casing 2 is shaped like a bowl or an inverted hemisphere, the upper opening of which is connected to the rim of the upper casing 1. The interior of the lower casing 2 is a downward-opening chamber that forms the ballast tank.The ballast tank is not sealed, but connected to the surrounding water via several inlet openings 3 on the side walls and bottom of the lower housing 2. The outer surface of the lower housing 2 is light-colored, for example white, light gray, or light yellow, and forms a clear visual contrast to the dark color of the upper housing 1. The inlet openings 3 can also be arranged separately on the side walls or bottom of the lower housing 2. The upper housing 1 and the lower housing 2 are fastened together by a connecting mechanism, thus forming a complete float body. The specific type of connection can be any method known to a person skilled in the art that enables a stable connection, for example, but not limited to, gluing, welding, bolting, or locking. The operating principle and self-stabilizing effect of this floating sphere device are as follows: when the device is deployed on the surface of a reservoir, its initial position, influenced by its own weight and buoyancy, is typically such that the lower housing 2 partially submerges. At this point, the surrounding water flows naturally through the inlet openings 3 into the ballast tank of the lower housing 2. With the continuous inflow of water, the volume of water in the ballast tank gradually increases, significantly lowering the center of gravity of the entire floating sphere device. This process occurs automatically and requires no external intervention.Finally, the entire device stabilizes in a state of equilibrium: most of the buoyancy is provided by the sealed main buoyancy chamber in the upper casing 1, while most of the mass (weight) is provided by the water in the ballast tank of the lower casing 2. This configuration, with "light at the top and heavy at the bottom" and "buoyancy at the top and pressure at the bottom," causes the device's overall center of gravity to lie well below its center of buoyancy, creating a mechanical effect similar to that of a "roly-poly toy," i.e., a self-stabilizing effect. In the event of wind and wave disturbances, the device generates a counter-moment, enabling it to resist tilting and tipping and to quickly return to an upright position once the disturbance ceases.This allows a water surface covering consisting of thousands of such floating spheres to maintain a uniform and dense distribution in the long term, effectively shielding the water surface, reducing evaporation pathways, and thus achieving permanent and efficient evaporation suppression. In the present embodiment, automated and cost-effective weight balancing is achieved by using the surrounding water as ballast in open ballast tanks. Filling the tanks with water as ballast physically lowers the center of gravity, thereby fundamentally solving the technical problem of the high center of gravity and the susceptibility to tipping inherent in conventional sealed float spheres, and achieving excellent dynamic stability. The design with differently colored upper and lower housings 2 not only serves functional purposes but also lays the foundation for potential future visual monitoring. In one embodiment, the upper housing 1 and the lower housing 2 are connected by locking lug components evenly distributed in the circumferential direction, wherein the locking lug component comprises a locking hook arranged at the edge of the upper housing 1 and a locking base arranged at the edge of the lower housing 2, which lock into each other by vertical downward pressure. In the present embodiment, the upper housing 1 and the lower housing 2 are mechanically connected and locked by locking lug components evenly distributed around the circumference. The hook is fixedly attached to the inside of the lower edge or to the connecting surface of the upper housing 1. The end of the locking hook is provided with an outwardly directed protrusion or barb structure. The locking base is fixedly attached to the outside of the upper edge or to the connecting surface of the lower housing 2, its position corresponding to the locking hook. Inside the locking base, a recess or chamber is formed that corresponds to the barb shape of the locking hook. The locking lug components are evenly distributed along the circumference of the connecting surface between the upper and lower housings 2.Depending on the diameter of the float ball, 6 to 8 sets of locking lug components are usually sufficient to ensure a consistent and reliable connection force. During assembly, the upper housing 1 is aligned with the lower housing 2, ensuring that the locking hook and the locking base are essentially flush. Pressure is then applied downwards in the axial direction (i.e., perpendicular to the equatorial plane of the float ball). The leading edge of the locking hook contacts the leading edge of the locking base, deforms elastically under the pressure, and slides into the interior of the locking base. Once the barb of the locking hook has fully traversed the locking shoulder inside the locking base, it returns to its original shape due to the material's elasticity, with the barb and locking shoulder forming a mechanical lock. In one embodiment, the mold closing line between the upper housing 1 and the lower housing 2 has a locally reinforced structure formed by the blow molding tool, the thickness of which is greater than that of the middle part of the housing, wherein the mold closing line of the upper housing 1 is located at the position of the equatorial plane of the float ball. In the blow molding process, the molded part is compressed at the mold closing edge, cut, and fused, creating a mold closing line surrounding the product. This line is typically the weakest point in terms of the overall product's structural strength and its resistance to cracking caused by environmental stresses. In reservoir floats, which are exposed to wind, waves, sunlight, and collisions on the water's surface over long periods, the weak mold closing line of conventional blow-molded parts is highly prone to cracking, leading to water ingress into the main buoyancy chamber and subsequent failure; this is the primary reason for their limited lifespan. The solution in this embodiment involves structurally reinforcing the mold closing line.In particular, a special mold closing edge design is used during the blow molding of the upper housing 1 and the lower housing 2. This design results in a significantly greater wall thickness at the mold closing line formed in the product than the wall thickness in the central area of ​​the housing, which is not affected by the mold closing line. For example, if the wall thickness of the main body of the upper housing 1 is designed to be 1.5 mm, the wall thickness in the area of ​​the mold closing line can be increased to 2.0 to 2.3 mm through the mold design. This local reinforcement structure is not added subsequently but is an integrated structure created directly during the molding process by the blow molding tool. The increased wall thickness is achieved by optimizing the mold closing edges. In a preferred embodiment, the mold closing edges of the upper and lower molds are not simply joined together flat, but are designed as offset cutting edges with a concave upper and a convex lower side, or as a structure with an obliquely oriented cross-cutting surface. At the moment of compression, the cutting edges of the upper and lower molds interlock, forcing more molten mold material into the compression line area instead of completely cutting it off as a burr. This physically increases the material accumulation and thickness at this point. Simultaneously, this compression action causes the material's molecular chains at the compression line to intertwine and fuse more strongly under high temperatures and pressures, increasing weldability and crystallinity and fundamentally improving the mechanical properties. The present embodiment transforms the inherent weakness of the conventional blow molding process (the mold closure line) into a structural strength, thereby increasing the overall service life of the floating ball device with respect to impact and fatigue resistance, without increasing the overall weight of the material or requiring complex post-treatment. In one embodiment, the inlet opening 3 is a through-hole which is formed during the blow molding of the lower housing 2 by synchronous piercing by a mandrel sliding axis mechanism integrated into the mold and has a diameter of 3 mm to 5 mm. In the conventional manufacturing process, openings in the sidewalls, such as the inlet ports 3, typically have to be produced after blow molding of the plastic product by separate post-processing steps such as drilling, punching, or hot melt stamping. This "post-processing" mode has significant disadvantages: low production efficiency, increased cycle times and labor costs; inconsistent hole quality, which can easily lead to burrs, cracks, or stress concentrations; poor hole consistency; and difficulties in producing high-density, high-precision hole groups on curved housings. For evaporative cooling floats that need to be mass-produced and require dozens of inlet ports 3 in each lower housing 2, conventional methods represent the greatest cost and quality bottleneck. In the present embodiment, a mandrel-sliding-axis mechanism is integrated into the blow molding tool for forming the lower housing 2. This mechanism essentially consists of a mandrel-shaped element and a sliding axis (or a cylinder) that drives its reciprocating movement. The material of the mandrel-shaped element and the shape of the tip are specially designed and characterized by high strength, high heat resistance, and low adhesion. This innovative process runs synchronously with the blow molding cycle. The specific sequence is as follows: Step 1: Mold closing and inflation. The mold is closed, and the molded part is clamped to the mold closing edge. Compressed air is then introduced into the molded part so that it fits tightly against the mold wall (including the preset position of the mandrel tip), cools, and hardens, thus provisionally creating the shell-like configuration of the lower housing 2. Step 2: Ejection and piercing with the sliding axis. In a critical time window after the molded part has been inflated but not yet fully cooled and hardened, the control system drives the sliding axis forward. The mandrel integrated into the mold then extends precisely and at high speed perpendicular to the wall surface of the molded part, its tip piercing the still partially molten wall of the molded part.Step 3: Shaping under pressure and retraction. The mandrel-shaped element remains briefly at the puncture point (pressure holding) so that the plastic material redistributes and melts around the opening under pressure and residual heat, creating a smooth inner wall. Once the main body of the lower housing 2 has completely cooled and hardened, the sliding axis retracts the mandrel-shaped element to its original position in the mold. Step 4: Opening the mold and removing the molded part. The mold is opened and the formed lower housing 2 is ejected. At this point, the uniform inlet openings 3 are already formed at the predetermined positions on the side walls of the housing, so no further processing is required. In one embodiment, the light color is white or light grey, the dark color is black or dark grey, wherein the color contrast between the upper housing 1 and the lower housing 2 makes it possible to monitor the position of the float ball on the water surface using image recognition technology. In a further aspect, an embodiment of the present invention further provides a blow molding tool for manufacturing the self-stabilizing floating ball device, wherein the mold closing edge of the blow molding tool has offset cutting edges with a concave upper and a convex lower side and uses a squeeze cutting technique; wherein the blow molding tool further comprises: a mandrel sliding axis opening mechanism comprising a mandrel-shaped structure with a sliding axis integrated into the mold of the lower housing; a temperature control system for separate temperature control in the area of ​​the mold closing line. The staggered arrangement of the cutting edges with a concave upper and a convex lower side creates a mechanical locking effect when the mold closes, increasing the material thickness at the mold closing line; the squeeze-cut design ensures that excess material is pressed inwards when the mold closes, forming a reinforcing rib structure; a precise temperature control system enables zoned temperature control of the mold, with the area of ​​the mold closing line being controlled separately to improve the crystallinity of the material; preferably, the mold closing line of the upper housing runs parallel to the horizontal plane, thereby increasing the impact resistance of adjacent spheres. By integrating a mandrel-shaped structure with a sliding axis into the mold for the lower housing, the formation of the inlet openings is completed simultaneously with the mold closing. Specifically, the mandrel-shaped structure protrudes when the mold closes, penetrates the wall of the molded part, retracts after pressure holding and cooling, and thus forms uniform inlet openings; this design enables precise control of the hole diameter and distribution density. In a further aspect, an embodiment of the present invention provides a method for manufacturing the self-stabilizing floating ball device, comprising the following steps: forming the upper housing 1 and the lower housing 2, each by means of a blow molding process; assembling the formed upper housing 1 and lower housing 2 by means of a connecting mechanism; placing the assembled floating ball device in a movable tempering box and performing a tempering treatment according to a predetermined temperature curve to eliminate internal stresses. The present embodiment further provides a method for manufacturing the self-stabilizing floating ball device. Through an optimized process flow, the method organically combines separate manufacturing, assembly, and post-treatment, aiming to efficiently and with high quality produce a performance-stable floating ball for evaporation suppression. The method essentially comprises the following three core steps S10, S20, and S30. S10: Forming the upper housing 1 and the lower housing 2 each by means of a blow molding process; This step corresponds to the component manufacturing phase. Using conventional blow molding machines, the upper housing 1 and the lower housing 2 are each fitted with special blow molds. The pre-mixed thermoplastic raw material (e.g., high-density polyethylene, HDPE) is heated, melted, and extruded into a mold, which is then placed into the respective mold. After the mold is closed, compressed air is blown into the mold, causing it to expand and fit tightly against the inner wall of the mold, where it cools and takes its final shape. The mold is then opened, and the product is removed, resulting in the blanks for the upper housing 1 and the lower housing 2 with their basic structural form. Preferably, the thermoplastic material is in particular: Main material: High-density polyethylene (HDPE), melt flow index 0.8-1.2 g / 10 min (190°C, 2.16 kg); Anti-aging system: Carbon black: 2.5-3.0% (by weight), serves as UV protection; Butane-2,5-dicarbonate: 0.4-0.5% (by weight), serves as a light stabilizer; Organic phosphites: 0.1-0.2% (by weight), serve as antioxidants; Color masterbatch: Upper casing: Addition of light gray masterbatch (TiO2-based), amount added 4-6%; Lower casing: Addition of dark gray masterbatch (carbon black-based), amount added 3-5%. The blow molding process includes: Molding temperature: HDPE, 190-210°C; Blowing pressure: 0.8-1.2 MPa; Cooling time: 10-60 s (to be adjusted depending on wall thickness); Clamping force: 60-80 kg (for floating spheres with a 10 mm diameter). S20: Assembling the molded upper housing 1 and lower housing 2 using a connection mechanism; this step corresponds to the component assembly phase. The upper housing 1 and lower housing 2 produced in step S10 are moved to the assembly position. Using a predetermined connection mechanism, they are joined to form a complete float sphere device. The connection mechanism can be one of the methods commonly used in this field that provides a stable connection between the two parts, for example, a snap-fit ​​locking mechanism, a threaded connection, or welding by heating the joining surfaces with a hot plate. The objective of this step is to physically connect and seal the two housings to form an initial float sphere that incorporates the basic functional structures of a main buoyancy chamber and ballast tank. S30: Placing the assembled floating ball device in a mobile tempering chamber and performing a tempering treatment according to a predefined temperature curve; Mobile tempering chamber: The tempering chamber is not a large tempering oven permanently installed in the workshop, but a self-contained, mobile unit with complete heating, temperature control, and heat storage functions. The housing typically features a double-walled, thermally insulated construction, integrating heating elements such as heating wires and PTC ceramic heaters, as well as high-precision temperature sensors and PID temperature controllers. The housing is equipped with casters on the bottom or can be loaded directly onto a transport vehicle. Temperature Control Procedure: A batch of floating ball devices, assembled according to step S20, is loaded into the cavity of the temperature control box. After closing the box door, the temperature control process is started, and the controller operates automatically according to a predefined temperature curve. A typical temperature control curve for HDPE material serves as an example: Heating Phase: The temperature in the box is increased uniformly from room temperature to the target temperature, for example, 95 ± 2°C, at a maximum rate of 50°C / hour. Holding Phase: The temperature is held at the target temperature for 2.5 to 3 hours. During this process, the molecular chains of the plastic gain sufficient activity, and the internal stresses in the product that arose during blow molding and cooling are completely relieved. Cooling Phase: The active heating is switched off, and the temperature is controlled by adjusting the cooling rate (e.g.,≤ 30°C / hour) or reduced to below 40°C by natural cooling in the box. After the tempering process, the residual stresses inside the float ball device are largely eliminated. This effectively prevents the float ball from suffering stress cracks, deformations, or performance losses during long-term outdoor use due to ambient temperature fluctuations, sunlight, or impact forces, thus significantly improving the dimensional stability and long-term durability of the product. For PP material, the temperature is increased to 100 ± 2°C and held for 1.5 to 2 hours, then it is cooled in the box. In one embodiment, the tempering process is carried out during the step of placing the assembled floating ball device in a movable tempering chamber. This tempering process, performed according to a predefined temperature curve, eliminates internal stresses during transport of the floating ball device to its deployment location at the reservoir. The tempering chamber is mounted on the transport vehicle, thus integrating production, tempering, and logistics. A lithium battery unit combined with a solar charging system can be used as the power supply. In a further aspect, an embodiment of the present invention provides a method for suppressing evaporation in reservoirs, comprising the following steps: deploying the floating ball device on the water surface of the reservoir, ensuring that the lower housing 2 is immersed in the water first so that the ballast tank automatically fills with water via the inlet openings 3; capturing images of the floating ball array on the water surface by means of an image recognition-based monitoring system and automatically identifying and locating defective floating balls that have turned over or tilted, based on the visible ratio between the dark upper housing 1 and the light lower housing 2 in the images. The present embodiment further provides a method for suppressing evaporation in reservoirs using the self-stabilizing floating ball device. The core of this method lies in the fact that not only is physical evaporation suppressed by the floating ball, but also, through an intelligent monitoring system, automated and visual monitoring of the operating status of the large-area floating ball array is enabled. This solves the problems of inefficient and costly manual inspections in traditional maintenance. The method essentially comprises the following two core steps, U10 and U20. U10: Deployment of the floating sphere device onto the surface of the reservoir, ensuring that the lower casing 2 enters the water first; this step corresponds to the initial deployment phase. A large number of self-stabilizing floating sphere devices are deployed onto the surface of the target reservoir in a suitable manner (e.g., manually, with a deployment vessel, or an automatic deployment device). During deployment, the position must be checked to ensure that the lower casing 2 of the floating sphere enters the water first or perpendicularly. Once the lower casing 2 touches the water surface, the surrounding water flows naturally through the inlet openings 3 located thereon into the ballast tank. As the ballast water fills, the center of gravity of the floating sphere shifts downwards, causing it to automatically align itself in a stable, upright floating position.The dark part of the upper shell 1 protrudes mostly from the water, while the light part of the lower shell 2 lies underwater or is only visible near the waterline. A large number of float spheres form a highly effective evaporation-suppressing layer on the water's surface. U20: Automated monitoring and fault detection based on image recognition; Monitoring system setup: The image recognition-based monitoring system consists primarily of an image acquisition unit and an image processing unit. The image acquisition unit can be a fixed camera at an elevated point on the shore, a drone over the reservoir, or a satellite. The image processing unit can be a local server or a cloud computing platform. Image acquisition and feature extraction: The system controls the image acquisition unit periodically or in real time to capture high-resolution images or video streams covering the entire floating sphere array.This is made possible by the design with the strong color contrast between the upper housing 1 (dark) and the lower housing 2 (light) of the float device; Principle of the malfunction detection algorithm: The image processing unit executes a specific image recognition algorithm (e.g., a program based on the OpenCV library). The core logic for detecting and locating defective floats consists of analyzing the statistical characteristics of the color pixels within the image area of ​​a single float: Normal state criterion: For a preset image analysis window containing a single float, the algorithm determines the area fraction of the dark pixels (corresponding to the upper housing 1). If this fraction is above a preset upper threshold (e.g., >85%), the float is classified as upright and in normal condition.Criteria for the defective state: If the float sphere is significantly tilted or completely inverted due to an internal leak, a defective connection, or external influences, a larger portion of the bright lower casing 2 will be above the water's surface. In this case, the area fraction of bright pixels in the same analysis window increases significantly. If the algorithm detects that the proportion of dark pixels in a specific target area falls below a preset lower threshold (e.g., <60%) or that bright pixels form a large continuous area, the float sphere is classified as "defective." Location: Simultaneously, the algorithm captures the pixel coordinates of this anomalous area in the image and converts them into actual geographic coordinates of the reservoir (e.g., GPS coordinates) using georeferencing technology, thus enabling precise location of the defective float sphere. In one embodiment, the method, after identifying a defective floating sphere, further comprises the following: dispatching an unmanned vessel with a visual tracking function to the location of the defective floating sphere in order to automatically recover it. Alternatively, a drone can be used to turn the floating sphere over. In one embodiment, the floating ball devices are deployed by means of a deployment ship or vehicle with an automatic deployment function, wherein the deployment device controls the distance between adjacent floating balls according to a preset deployment density so that they are close together, for example with a distance of 10 cm to 15 cm. Although the embodiments of the present invention are described with reference to the accompanying drawings, those skilled in the art may make various modifications and variants without departing from the spirit and scope of the present invention; such modifications and variants all fall within the scope defined by the accompanying claims. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature CN 105905247A

[0003] CN 222686893U

[0005] CN 223148653U

[0005]

Claims

A self-stabilizing floating sphere device comprising an upper casing (1) and a lower casing (2) connected to each other, characterized in that the interior of the upper casing (1) forms a sealed main buoyancy chamber, the outer surface of which is dark in color; wherein the interior of the lower casing (2) forms an open ballast tank, the side walls and / or bottom of which are provided with several inlet openings (3) through which water can enter, and the outer surface of which is light in color; wherein the upper casing (1) is flat-spherical and hollow, provides the main buoyancy and is separate from the lower casing; wherein the design of the ballast tank enables the floating sphere device to automatically take on ballast water when deployed on the water surface in order to lower the center of gravity, achieve self-stability and at the same time ensure resistance to wind, waves and tipping. Self-stabilizing floating ball device according to claim 1, characterized in that the upper housing (1) and the lower housing (2) are connected by locking lug components distributed uniformly in the circumferential direction, wherein the locking lug component comprises a locking hook arranged at the edge of the upper housing (1) and a locking base arranged at the edge of the lower housing (2), which lock into each other by vertical downward pressure. Self-stabilizing floating ball device according to claim 1, characterized in that the mold closure line between the upper housing (1) and the lower housing (2) has a locally reinforced structure formed by the blow molding tool, the thickness of which is greater than that of the middle part of the housing, wherein the mold closure line of the upper housing (1) is located at the position of the equatorial plane of the floating ball. Self-stabilizing floating ball device according to claim 3, characterized in that the inlet opening (3) is a through-hole which is formed during the blow molding of the lower housing (2) by synchronous piercing by a mandrel sliding axis mechanism integrated into the mold and has a diameter of 3 mm to 5 mm. Self-stabilizing floating ball device according to claim 1, characterized in that the light color is white or light grey and the dark color is black or dark grey, wherein the color contrast between the upper housing (1) and the lower housing (2) makes it possible to monitor the position of the floating ball on the water surface by means of image recognition technology. A blow molding tool used for manufacturing the self-stabilizing floating ball device according to any one of claims 1 to 5, characterized in that the mold closing edge of the blow molding tool has an offset cutting edge with a concave upper and a convex lower side and uses a squeeze cutting technique; wherein the blow molding tool further comprises: a mandrel sliding axis opening mechanism comprising a mandrel-shaped structure with a sliding axis integrated into the mold of the lower housing; a temperature control system for separate temperature control in the area of ​​the mold closing line.

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