System for process-reliable production of pipe connections

Abstract

System (1) for the production of pipe joints, comprising: - a power-operated tool (2) designed to slide a press ring onto a joint between two pipe ends, thereby creating a permanently hermetically sealed connection between the pipe ends by cold pressing, - a drive unit (3) designed to supply the power-operated tool (2) with drive energy, - a sealant applicator (4) designed to apply a sealant to the surface of at least one of the pipe ends before the pipe ends are joined, - a sealant reservoir (6) and - a sealant metering control device (7) designed to dispense a predetermined quantity of sealant from the sealant reservoir (6) to the sealant applicator (4) for application to the surface of the pipe end.

Description

[0001] The invention relates to a system for producing pipe connections using a press ring which is pushed onto a connection point of two pipe ends, thereby producing a permanent and hermetically sealed connection of the pipe ends by cold pressing.

[0002] The production of pipe connections using Lokring technology is based on a cold pressing process, which is particularly common in the industrial production of refrigerators and air conditioners. Specially shaped press rings (Lokrings) are used, whose specific internal contour causes a controlled cold forming of the pipe ends to be joined. This results in a high-strength and leak-proof connection that requires no welding or brazing and is therefore particularly suitable for use in hermetic refrigeration circuits.

[0003] Depending on the application, there are two main variations of this process. In the first variation, which uses a single press ring per pipe connection, two pipe ends to be joined are pushed together, one of which has been mechanically expanded beforehand to allow for a defined overlap. The press ring is then moved axially over the joint using a hydraulic tool. Due to the ring's internal contour, the pipe ends are selectively cold-formed, creating a form-fit and force-fit connection. The resulting plastic deformation of the pipe ends ensures a permanently tight and mechanically robust connection.

[0004] The second variant includes two compression rings and a connecting piece for each pipe connection, which serves as an intermediate piece. In this case, the two pipe ends to be joined are inserted into the connecting piece. The compression rings are then pushed onto both sides of the connection points and moved over the pipe ends and the intermediate piece by the hydraulic tool. Due to the geometry of the compression rings, the pipe ends are also cold-formed and pressed against the fitting. This method also ensures that the connection is not only mechanically stable but also permanently gas- and liquid-tight.

[0005] A crucial aspect for the tightness of the connection is the application of a sealant, which is applied to the (inner and / or outer) surface of at least one of the pipe ends before crimping. This sealant ensures that any microscopic irregularities between the contact surfaces of the pipes and, if applicable, the fitting, are reliably filled. Since this is a permanent connection, the sealant must exhibit high long-term resistance to mechanical and thermal stresses. In practice, special refrigerant- and oil-resistant sealants are used for this purpose, ensuring that the connection remains hermetically sealed throughout the entire service life of the device.

[0006] The tool used for the crimping process, i.e., for pushing on the crimp ring(s) in industrial manufacturing processes, is typically a hydraulically operated pliers supplied with hydraulic fluid (pressurized oil) by a hydraulic power unit. This unit generates the required pressure, which is transmitted via one or more lines to the manually or robotically operated tool. The tool has an axially movable mechanism that pushes the crimp ring(s) over the joint of the pipe ends with a defined force. The hydraulic control ensures that the crimping process is carried out with high precision and repeatability, which is particularly important for industrial mass production.

[0007] Starting from this, the object of the invention is to provide a system for the production of pipe connections, which is improved in particular with regard to industrial application in the mass production of refrigerators or air conditioners.

[0008] The invention proposes a system for manufacturing pipe connections, comprising the following: - a power-operated tool designed to slide a press ring onto a joint between two pipe ends, thereby creating a permanently hermetically sealed connection between the pipe ends by cold pressing, - a drive unit designed to supply the power-operated tool with drive energy, - a sealant applicator designed to apply a sealant to the surface of at least one of the pipe ends before the pipe ends are joined, - a sealant reservoir and - a sealant dosing control device designed to dispense a predetermined quantity of sealant from the sealant reservoir to the sealant applicator for application to the surface of the pipe end.

[0009] The proposed system represents a precise and automatable solution for manufacturing pipe connections, particularly suitable for industrial production of cooling systems and air conditioning units. It combines several functional units specifically designed to ensure a permanently hermetically sealed connection of (primarily metallic) pipe ends.

[0010] The core component of the system is the power-operated tool, which is designed to push a press ring over the joint between two pipe ends. As previously described, this press ring has a defined internal contour that, when pushed onto the joint, causes a controlled plastic deformation of the pipe ends. The pressing process itself is controlled by the drive unit, which supplies the tool with drive energy.

[0011] The power-operated tool can preferably be hydraulically actuated, with the drive unit being a hydraulic power unit designed to supply the hydraulically actuated tool with hydraulic fluid. The hydraulic power unit provides the required pressure and ensures controlled movement of the hydraulic tool so that the press ring is pushed on with the required force and speed.

[0012] A key feature of the proposed system is the integrated sealant application. This involves using a sealant applicator (either handheld or robotic) that applies the sealant to the surface of at least one of the pipe ends before the connection is made. The sealant is drawn from a reservoir, ensuring a constant supply to the applicator. To guarantee precise and reproducible dosing, the sealant dosing control unit is integrated into the system. This unit ensures that a predetermined, adjustable quantity of sealant is dispensed to the applicator, enabling both uniform coating of the pipe ends and efficient use of the sealant. This control allows the sealant to be precisely tailored to the specific requirements of the pipe material, the refrigerant system, and the operating conditions.

[0013] The integrated sealant application offers the advantage of controlling and monitoring the sealant application process. This represents a significant improvement over the state of the art, increasing both process reliability and the reproducibility of the connections. Monitoring of the dispensed sealant quantity is achieved, for example, through volumetric flow measurement. This ensures adherence to the process parameters relevant to the pipe connection. Each connection is supplied with the required amount of sealant. Errors or irregularities in the sealant application can thus be avoided. The system can automatically issue a warning or interrupt the production process if, for example, the dispensed sealant quantity does not correspond to the specified value or the sealant reservoir is exhausted.This prevents the formation of connections without or with insufficient sealant coating, which could potentially exhibit leaks or mechanical weaknesses. Since sealant application plays a crucial role in compensating for surface roughness and microscopic leakage paths, its thorough inspection is of particular importance for quality assurance.

[0014] One possible configuration of the system involves the sealant dosing control device being connected to the drive unit and / or the power-operated tool via a signal transmission system. In this configuration, the control is set up so that the tool for creating the pipe connection is only activated once the sealant application has been successfully completed. This means that the tool is only released after confirmation of the sealant dispensing, thus ensuring that each connection is supplied with the correct amount of sealant before the grouting process begins.

[0015] The function of this process-safety-oriented release mechanism is based on a signal flow between the sealant dosing control unit and the tool or hydraulic system. As soon as the sealant has been drawn from the reservoir and dispensed through the sealant applicator, the control unit enables the drive unit or directly the tool to perform the cold crimping. If the sealant has not been applied or has been applied in insufficient quantity, the crimping process is blocked, and the system can issue a warning message so that corrective action can be taken before a faulty connection occurs.

[0016] The advantage of this control system lies in increased process reliability and quality assurance. Since the application of the sealant plays a crucial role in the long-term tightness of the connection, this design prevents connections from being made without or with insufficient sealant. The mandatory sequence of process steps – first sealant application, then compression – ensures consistently high quality for every single connection.

[0017] One possible configuration of the system involves the sealant dosing control device being set up to only allow the tool for creating the pipe connection to be operated within an adjustable time window after the sealant has been dispensed. This means that after the sealant has been applied, there is a defined period within which the crimping process must be completed. If this time window is exceeded, the tool is locked, and a new application of sealant is required before the connection can be made.

[0018] The function of this time limit is based on the physical and chemical properties of the sealant. Many sealants have a limited working time during which they maintain their optimal flow and adhesion properties. After this period, evaporation, curing, or a change in viscosity can occur, which can impair the sealant's ability to compensate for microscopic irregularities and ensure a reliable seal. The control system thus ensures that the grouting process only takes place under ideal conditions.

[0019] A key advantage of the time-limited release is therefore the assurance of consistently high connection quality. Since the sealant is applied and compressed within the optimal processing window, its function as a sealant is fully maintained.

[0020] If the time window is exceeded, the system can issue a warning or automatically interrupt the process to prevent a faulty connection. In such a case, a new application of sealant would be required before the connection could be made.

[0021] Furthermore, this design contributes to the complete traceability and documentation of the manufacturing process. Since each sealant application and its compression within a defined time window is recorded, it can be verified at any time whether the process was followed correctly. This is particularly important in regulated industries where seamless quality control is required. The ability to individually adjust the time window depending on the sealant type and environmental conditions ensures the system remains flexible for various applications and can be optimally adapted to different production requirements.

[0022] Another possible configuration of the system involves the sealant dosing control device having a communication interface for connection to a Manufacturing Execution System (MES). An MES is a software-based production management system that connects a company's manufacturing level with the higher-level planning and control level (e.g., ERP systems). It records, monitors, and controls all relevant production processes in real time to ensure efficiency, quality, and traceability. Integrating the sealant dosing control device into an MES enables comprehensive control, documentation, and optimization of the pipe fitting manufacturing process, including sealant application, throughout the entire production process.

[0023] The function of the communication interface is to transmit the sealant application and associated process parameters directly to the MES (Manufacturing Execution System) for processing. This includes, for example, the exact amount of sealant applied, the application time, the ambient conditions, and adherence to the specified process time windows between application and compression. The MES can analyze this data and link it with other manufacturing parameters to ensure seamless quality control. If deviations are detected, the MES can automatically initiate countermeasures, such as issuing a warning, marking defective components, or suggesting adjustments to the sealant parameters.

[0024] A key advantage of MES integration is the complete traceability of all manufactured pipe connections. Because each manufactured product is uniquely identifiable and all relevant process data is stored, it is possible to verify at any time whether a connection was made correctly. This is particularly important in industries with high quality requirements, such as refrigeration and air conditioning. Should a leak or defect be detected later, the data history enables precise root cause analysis, allowing for targeted improvement measures to be derived.

[0025] Another advantage lies in predictive maintenance and process optimization. Through continuous monitoring of the sealant application, the MES can detect deviations early on that indicate wear or malfunctions, such as a gradual change in sealant viscosity or a decrease in dispensing efficiency. In such cases, the system can suggest maintenance measures or automatically adjust the sealant dispensing to ensure consistent quality. This reduces unplanned downtime and maximizes production efficiency.

[0026] In addition, MES integration offers the possibility of flexibly adapting sealant application to different production requirements. Since modern production lines often manufacture a wide variety of products, the MES can automatically specify the optimal parameters for sealant application depending on the product type. For example, different pipe diameters, materials, or environmental conditions can be taken into account to ensure a consistently optimal amount of sealant.

[0027] Another possible configuration of the system involves the sealant dosing control device executing a sequence of sealant dispensing with individually adjustable quantities. The sequence and quantities are programmable via the communication interface and can be automatically adapted to different product variants.

[0028] The key advantage of this design lies in the precise control of sealant application for each individual connection. Particularly with assemblies containing different pipe diameters or materials, each connection can be precisely calibrated. This prevents errors, reduces scrap, and minimizes rework, as it ensures that every connection is treated correctly. Furthermore, the automated sequence control increases process reliability by preventing errors caused by incorrect sealant quantities or connection sequences.

[0029] Integration into the MES allows parameters to be flexibly adapted to different products, increasing manufacturing efficiency and flexibility. Automating this process optimizes material usage, ensures consistent quality, and guarantees reliable, cost-effective production of hermetic pipe connections, particularly in the mass production of cooling systems and air conditioning units.

[0030] The sealant dosing control device can be configured to detect, store, and output the sealant reservoir level via the communication interface. This enables continuous monitoring of the sealant supply and early warnings when the level is low, thus preventing unplanned production interruptions.

[0031] Storing the data allows for the analysis of consumption patterns and the optimization of maintenance intervals. Outputting the data to the MES enables automated inventory management and timely reordering. This increases process efficiency, reduces downtime, and ensures consistent quality of pipe connections.

[0032] In another possible configuration, the sealant dosing control device can record, store, and output data on sealant dispensing processes, dispensed quantities, and tool actuations via the communication interface. The signal connection to the drive unit can also be used to record, for example, the time profile of the hydraulic pressure during each crimping operation performed with the tool, enabling detailed process monitoring.

[0033] This data ensures complete documentation and quality control by making every connection with its associated parameters traceable. For example, recording the hydraulic pressure profile allows for the detection of irregularities in the crimping process, such as insufficient or excessive pressure, which can indicate material deviations, tool wear, damage to the pipe ends or the crimping ring used, as well as malfunctions in the hydraulic system.

[0034] The data can be used to optimize sealant quantity and crimping force, to detect deviations early, and to prevent faulty connections. Output to the MES enables centralized monitoring and analysis, allowing process fluctuations to be identified and corrective actions to be initiated. Furthermore, the continuous recording of these parameters supports predictive maintenance by detecting wear or functional deviations in a timely manner, before production downtime occurs.

[0035] Enhanced monitoring according to this design increases process reliability, minimizes rejects, and ensures consistently high joint quality. At the same time, traceability is improved, which is particularly important for regulated industries where complete documentation of joining processes is required.

[0036] An embodiment of the invention is described in more detail below with reference to the drawing. It shows: Fig. 1 Schematic representation of a system according to the invention.

[0037] The in Fig.System 1, designated as a whole by 1, for producing pipe connections comprises several coordinated components that enable the precise and automated execution of the cold pressing process described above for producing pipe connections. The central element of system 1 is the hydraulically actuated tool 2, which is designed to push a press ring (not shown) over a joint between two pipe ends (also not shown). The press ring causes a controlled plastic deformation of the pipe ends, thereby creating a permanently hermetically sealed connection. The hydraulic tool 2 is supplied with hydraulic fluid by a hydraulic power unit 3, which is connected to the tool 2 via one or more flexible hydraulic lines.Hydraulic pressure is supplied via an integrated hydraulic pump (not shown) and switchable hydraulic valves 12, which enable precise control of the tool 2.

[0038] Furthermore, System 1 features a sealant applicator 4, which serves to apply a defined quantity of sealant to the surface of at least one of the pipe ends before crimping. This ensures a seal at the joint by compensating for microscopic irregularities between the pipe ends. To facilitate handling of the sealant applicator 4, it is suspended from a pulley 5, which counterbalances the applicator's weight and allows for ergonomic use by the operator. The sealant required for application is stored in a sealant reservoir 6, from which the applicator 4 is continuously supplied.

[0039] The sealant dispensing is controlled by a sealant metering control device 7, which is connected to the sealant reservoir 6 and the applicator 4 via hoses 8 and 9. The main function of the sealant metering control device 7 is to extract a precisely defined quantity of sealant from the reservoir 6 and deliver it to the applicator 4, thus ensuring precise and reproducible application. The sealant metering control device 7 is connected to the hydraulic power unit 3 via a control signal line 10. A control box 11, which is associated with the hydraulic power unit, receives control commands from the sealant metering control device 7 via the control signal line 10 and converts these into control signals for the hydraulic pump and the switchable hydraulic valves 12. This ensures that the hydraulic tool 2 is only actuated once the sealant application has been successfully completed.This prevents errors caused by insufficient sealant application and ensures a consistently high connection quality.

[0040] Another key feature of System 1 is the integration of the sealant dosing control device 7 into a higher-level Manufacturing Execution System (MES) 13. The sealant dosing control device 7 is connected to the MES 13 via a data line 14, enabling centralized programming, process monitoring, and documentation. The sealant dosing control device 7 can be programmed via this interface from the MES 13 to execute a sequence of sealant dispensing with individually adjustable quantities.

[0041] In addition to controlling the sealant dispensing, the sealant dosing control device 7 detects the fill level of the sealant reservoir 6, stores the corresponding data, and transmits it to the MES 13. This allows for early refilling of the sealant to prevent interruptions in the production process. Besides the fill level, data on the sealant dispensing events, the quantities dispensed, and the actuation of the hydraulic tool 2 are also recorded and stored. This information is transmitted to the MES 13 via data line 14, where it is used for process documentation.

[0042] The hydraulic pressure over time can also be recorded via control signal line 10 during each pressing operation. This data provides valuable information for process monitoring and quality assurance, as it allows conclusions to be drawn about possible deviations in the pressing process.

[0043] The combination of sealant monitoring, crimping control and MES integration ensures precise, reproducible and traceable production of pipe connections with high tightness and mechanical stability in an industrial manufacturing process, e.g. of refrigerators or air conditioners.

Claims

[1] System (1) for making pipe joints, comprising: - a power-operated tool (2) designed to slide a press ring onto a joint between two pipe ends, thereby creating a permanently hermetically sealed connection between the pipe ends by cold pressing, - a drive unit (3) designed to supply the power-operated tool (2) with drive energy, - a sealant applicator (4) designed to apply a sealant to the surface of at least one of the pipe ends before the pipe ends are joined, - a sealant reservoir (6) and - a sealant metering control device (7) designed to dispense a predetermined quantity of sealant from the sealant reservoir (6) to the sealant applicator (4) for application to the surface of the pipe end. [2] System according to claim 1, wherein the power-operated tool (2) is hydraulically actuated and the drive unit (3) is a hydraulic unit, configured to supply the hydraulically actuated tool (2) with hydraulic fluid. [3] System according to claim 1 or 2, wherein the sealant metering control device (7) is connected to the drive unit (3) and / or the power-operated tool (2) via signal transmission and is configured to release the tool (2) for the connection of the pipe ends only after the sealant has been dispensed. [4] System according to claim 3, wherein the sealant metering control device (7) is configured to allow actuation of the tool (2) for making the connection of the pipe ends only within an adjustable time window after the sealant has been dispensed. [5] System according to one of claims 1 to 4, wherein the sealant dosing control device (7) further comprises a communication interface for connection with a Manufacturing Execution System (13). [6] System according to claim 5, wherein the sealant dosing control device (7) is configured to perform a sequence of sealant dispensing with individually adjustable sealant quantities, wherein the number of sealant dispensings and the sealant quantities of the individual sealant dispensings of the sequence are programmable via the communication interface. [7] System according to claim 5 or 6, wherein the sealant dosing control device (7) is further configured to acquire and / or store data regarding the fill level of the sealant reservoir (6) and to output it via the communication interface. [8] System according to one of claims 5 to 7, wherein the sealant metering control device (7) is further configured to record and / or store data relating to the sealant dispensing processes, the quantities of sealant dispensed and the actuation processes of the tool (2) and to output them via the communication interface.

Images