A mould shell temperature measuring joint for an equiaxed crystal vacuum precision casting furnace mould lifting system

Abstract

This invention discloses a temperature measuring connector for a mold shell in a vacuum precision casting furnace mold lifting system, integrating the temperature measuring module with the lifting shaft. Multiple temperature measuring sections are symmetrically distributed along the central axis on both sides of the outer side of the lifting shaft near the top mounting plate, used to connect to thermocouples pre-embedded in the mold shell. The signals from the temperature measuring sections are connected to an external control system via a needle-type glass sintered sealing head fixed to the lifting shaft. This design significantly shortens the thermocouple leads, optimizes the signal path, reduces interference and wear, and provides protection through a protective sleeve and transition shell. This invention has a compact structure and significantly improves the reliability, stability, and ease of maintenance of temperature monitoring under high temperature and vibration environments.

Description

Technical Field

[0001] This utility model relates to the field of online monitoring technology for high-temperature precision casting processes. Specifically, it relates to a mold temperature measuring device for an equiaxed crystal vacuum precision casting furnace. More specifically, this utility model relates to a modular temperature measuring connector deeply integrated with the moving parts (lifting shaft) of the mold lifting system. This connector enables stable, reliable, and continuous acquisition and transmission of multi-point temperature signals from the ceramic mold shell under high-temperature, dusty, vibrating, and vertical movement conditions, and efficiently leads the signals to a fixed external control system. Background Technology

[0002] Equiaxed crystal vacuum precision casting is a key process for producing complex thin-walled castings (such as turbine blades for aero-engines) from high-performance nickel-based superalloys and titanium alloys. In this process, a ceramic mold is placed in a vacuum or inert atmosphere. After molten metal is poured into it, a precisely controlled lifting system lowers the mold at a specific speed to establish the required temperature gradient, thereby controlling grain growth and obtaining an ideal equiaxed crystal structure. Accurate and real-time monitoring of the three-dimensional temperature field evolution at key locations on the mold during casting solidification plays an irreplaceable role in verifying and optimizing process models, predicting and eliminating defects such as shrinkage porosity / hot cracking, and improving casting yield and performance consistency.

[0003] However, achieving reliable online temperature measurement in equiaxed crystal vacuum precision casting furnaces faces a series of severe challenges: Extreme Environment: After casting, the surface temperature of the mold shell can be maintained at 900°C to 1200°C for extended periods. Metal vapor condensation and ceramic fiber dust are present within the furnace. Simultaneously, continuous mechanical vibration from the lifting system is unavoidable. This combined condition of high temperature, dust, and vibration poses an extreme test to the material tolerance, sealing integrity, and mechanical stability of any electrical connection components. High temperatures not only accelerate material oxidation and creep but also cause stress at the joints of different materials due to mismatched coefficients of thermal expansion, leading to seal failure or loosening of connections. Dust and condensate can intrude into connection gaps, affecting electrical contact and even causing short circuits.

[0004] The challenge of motion connection: Temperature sensors (typically K-type or S-type armored thermocouples) need to connect from the moving mold shell, which moves up and down with the lifting system, to the stationary external data acquisition system. This connection point is at the interface between motion and stillness, requiring both ensuring the continuity and stability of the signal path under violent movement and solving the problem of wiring sealing and protection between moving and stationary parts. Traditional approaches often place the connection interface on the stationary frame of the furnace body, resulting in long leads from the moving mold shell to this interface that are in a dynamic bending state, becoming a weak link in system reliability.

[0005] Signal integrity and reliability: Long-distance signal transmission lines are prone to noise introduction in environments with strong electromagnetic interference (from furnace heating elements, electromagnetic stirring devices, etc.) and high-temperature radiation, leading to measurement signal distortion and drift. Thermocouple signals are inherently weak millivolt-level signals, making them highly susceptible to interference. Traditional flexible conductors are prone to insulation aging and embrittlement under long-term reciprocating motion and high-temperature baking, and the conductor metal core is at extremely high risk of fatigue fracture. Signal distortion or interruption will directly lead to inaccurate process control, potentially resulting in significant losses such as scrapping an entire furnace of castings.

[0006] Limitations of existing technology: Direct lead method: Long thermocouple wires are led directly from the mold shell to a fixed junction box outside the furnace. This method results in excessively long wires (often several meters to tens of meters), which are prone to tangling, scraping, and wear with other components inside the furnace during lifting and lowering. The long wires increase the resistance of the signal loop and the introduction of induced noise, leading to significant signal interference. The furnace body's through-wall sealing structure is complex, requiring multiple layers of high-temperature sealing and insulation, resulting in low reliability. Furthermore, once damaged, maintenance is almost impossible without shutting down the furnace.

[0007] Slip ring current collection: This method was once used on some rotating equipment, but when used for high-current, high-precision weak signal (thermocouple millivolt signal) transmission, the contact resistance is unstable, it is prone to wear and generates electrical noise, and its lifespan is extremely short in high-dust environments, making it unsuitable for high-precision temperature measurement. The fundamental reason is that the physical characteristics of sliding contact determine the inherent fluctuation of contact resistance, and it is impossible to maintain a stable low contact resistance for a long time in high-temperature, dusty environments.

[0008] Fixed quick-connect couplings: Quick-connect couplings are installed on the fixed frame of the furnace body, and the thermocouple on the mold shell is connected to it via a short lead. Although this shortens the lead on the mold shell side, the lead from the coupling to the control cabinet is still relatively long. Furthermore, the coupling itself, as a stationary component, is completely exposed to the high-temperature, dusty, and harsh environment of the middle or upper part of the furnace, posing a severe challenge to its long-term sealing and contact reliability. The elastic element inside the coupling is prone to stress relaxation at high temperatures, leading to a decrease in contact pressure; the sealing material may also fail due to high-temperature aging. In addition, this solution requires additional support structures and wiring space, making it difficult to arrange within the space-constrained precision furnace body and increasing the system's complexity.

[0009] In summary, none of the existing technical solutions have fundamentally solved the problem of transmitting weak signals with high reliability and precision between moving parts and stationary systems under extreme environments. Each solution sacrifices signal quality, reliability, or ease of maintenance, making it difficult to meet the increasingly stringent process monitoring requirements of modern high-performance precision casting processes.

[0010] Therefore, there is an urgent need in this field for an innovative temperature measurement signal connection solution that must be able to: withstand extreme environments; perfectly resolve the reliability of electrical connections between moving parts and stationary systems; minimize the exposed length of sensitive signal lines; and be highly integrated with existing lifting system structures for easy installation, maintenance, and mold replacement. This requires moving beyond traditional "external" or "static interface" design approaches and seeking an integrated solution that is deeply integrated with the motion actuator. Utility Model Content

[0011] To address the shortcomings of existing technologies, the purpose of this invention is to provide a temperature measuring connector for the mold shell of an equiaxed crystal vacuum precision casting furnace mold lifting system. Its main objective is to directly integrate the temperature signal acquisition interface onto the core moving component of the lifting system—the lifting shaft—achieving integration of the temperature measuring system and the actuator, fundamentally optimizing the signal path. It provides a signal transmission interface with extremely high sealing performance, electrical contact reliability, and mechanical durability in high-temperature, vibration, and dusty environments. It enables rapid, convenient, and reliable connection and disconnection between the thermocouple and the signal transmission system, accommodating frequent mold shell changes. It simplifies furnace wiring and improves the overall system compactness, reliability, and maintainability.

[0012] The above-mentioned utility model objective is achieved through the following technical solution: This utility model provides a mold shell temperature measuring connector for a mold lifting system of an equiaxed crystal vacuum precision casting furnace, including a lifting shaft and a mounting plate detachably fixed to the top of the lifting shaft. The mold shell is provided on the mounting plate. Three temperature measuring parts are symmetrically and evenly distributed on both sides of the central axis of the lifting shaft end face near the mounting plate. At both ends of the central axis, on the outer side of the lifting shaft, needle-inserted glass sintered sealing heads for connecting external wires to the temperature measuring parts are respectively installed. The needle-inserted glass sintered sealing heads are used to seal and isolate the internal conductive wires from the external environment. One end of the thermocouple is connected to the temperature measuring part, and the other end is connected to the temperature measuring point on the outer wall of the mold shell.

[0013] The core innovation of this solution lies in the fundamental change of the topology: the signal aggregation point, traditionally located on a static frame, is "migrated" to the moving component—the lifting shaft itself. This change brings multiple cascading advantages. First, the distance from the temperature measuring point on the mold shell to the temperature measuring part on the lifting shaft is minimized, typically requiring only a rigid or semi-rigid armored thermocouple of a few tens of centimeters for connection. This conductor hardly participates in the relative motion of lifting, avoiding dynamic bending fatigue. Second, signal transmission from the temperature measuring part to the external control system is mainly accomplished through conductors fixed inside or on the surface of the lifting shaft. These conductors are rigidly connected to the lifting shaft, with no relative motion, resulting in extremely high reliability. Finally, the electrical interface between motion and stationary states is condensed into one or two high-performance pin-mounted glass-bonded sealing heads. This component is located in the relatively low-temperature zone of the lifting shaft sidewall and employs mature glass-metal sintering sealing technology, enabling it to withstand extreme environments for extended periods, achieving "single-point" and "high-reliability" dynamic signal transmission.

[0014] According to one embodiment of the present invention, a fixing ring is detachably and fixedly connected to the outer periphery of the lifting shaft, and six temperature measuring parts are installed on the outside of the fixing ring.

[0015] The retaining ring design enables modular installation. As an independent assembly unit, it can be precision-machined and pre-assembled on a workbench, ensuring the installation accuracy and electrical isolation of multiple temperature measuring sections. The entire retaining ring assembly is then installed onto the lifting shaft, greatly simplifying on-site installation and subsequent maintenance. If a temperature measuring channel is damaged, the retaining ring can be partially disassembled for repair or the individual temperature measuring module can be replaced without requiring extensive disassembly of the entire lifting shaft or furnace structure.

[0016] According to one embodiment of the present invention, each temperature measuring unit includes a thermocouple socket, a first ceramic connector, a pad, and a second ceramic connector. The thermocouple socket is fixed on a fixing ring, the first ceramic connector is fixed on the thermocouple socket, the pad is fixed on the first ceramic connector, and the second ceramic connector is fixed on the pad. The first ceramic connector is connected to both the thermocouple socket and the second ceramic connector, and the second ceramic connector is connected to the thermocouple. The thermocouple socket is connected to the pin-mounted glass sintered sealing head via a wire.

[0017] The hierarchical structure of the temperature measurement section fully considers thermal management, electrical isolation, and mechanical protection. The thermocouple socket, serving as the electrical conversion base, is fixed to a relatively low-temperature retaining ring. The first ceramic connector undertakes the main electrical connection and high-temperature insulation tasks; its high-purity alumina ceramic provides excellent high-temperature insulation and a certain degree of heat radiation shielding. A backing plate further provides electrical isolation and isolates more direct heat radiation from the upper housing. The second ceramic connector, as the final user interface, directly mates with the thermocouple plug; its structure is optimized for frequent insertion and removal. This "hot and cold separation" design places the temperature-sensitive wire connection point (thermocouple socket) in a relatively lower, lower-temperature area, while placing the part that needs to withstand the high temperatures of insertion and removal (ceramic connector) at the front, extending the overall lifespan.

[0018] According to one embodiment of the present invention, a protective sleeve is detachably fixed to the bottom of the mounting plate. The protective sleeve is fitted over the outside of the temperature measuring part and is used to provide physical protection for the socket interface in the non-connected state.

[0019] The protective sleeve is a key component ensuring the long-term reliability of the connector. After the mold shell is disassembled or before installation, the second ceramic connector interface of the temperature measuring section is exposed and is highly susceptible to contamination from falling foreign objects, impacts from operating tools, or dust floating inside the furnace. The protective sleeve acts like a "safety helmet," providing a physical barrier for the precision interface without hindering the passage of thermocouple leads, preventing mechanical damage and excessive dust accumulation—a protective function that traditional open connectors lack.

[0020] According to one embodiment of the present invention, the needle-type aviation plug glass sintered sealing head includes a metal shell, at least one conductive needle penetrating the metal shell, and an insulating sealing glass body that is filled in the gap between the conductive needle and the inner wall of the metal shell by a high-temperature sintering process. One end of the conductive needle is welded to an external cable, and the other end forms an aviation plug male or female connector.

[0021] The pin-type glass sintered sealing head is the core component of this solution for achieving a highly reliable connection at the motion-to-stationary interface. It employs a process of co-melting and sintering glass and metal at high temperatures to form a truly integral sealing structure, rather than relying on elastomers such as rubber rings. This structure has the following irreplaceable advantages: 1) Absolute airtightness with extremely low leakage rate, meeting the requirements of vacuum or high-pressure protective atmospheres; 2) Excellent temperature resistance; the glass body and metal shell can withstand temperatures of several hundred degrees Celsius without performance degradation; 3) Excellent vibration resistance; the glass body firmly "embeds" the conductive pin in the shell, with no relative micro-movements and extremely stable contact resistance; 4) Long lifespan; its lifespan depends on the material lifespan of the glass and metal, far exceeding that of slip rings or ordinary connectors that rely on mechanical contact. It is the key to transforming the challenges of dynamic electrical connections into mature static sealing technology applications.

[0022] According to one embodiment of the present invention, the first ceramic connector and the second ceramic connector are plate-shaped structures made of high-temperature alloy, and are provided with elastic contact elements inside that match the insertion end of the thermocouple probe. The elastic contact elements are spring clips or crown springs made of beryllium bronze or nickel-based high-temperature alloy.

[0023] The specific structural design of ceramic connectors ensures reliable electrical contact at high temperatures. High-temperature alloys (such as Inconel) are used for the housing to ensure mechanical strength. The internal elastic contacts are crucial; beryllium bronze offers excellent elasticity and conductivity, while nickel-based high-temperature alloys maintain performance at even higher temperatures. In particular, the crown spring structure provides multi-point, large-area line or surface contacts. Compared to single-point contact spring pins, it offers lower contact resistance, better vibration resistance, and greater tolerance for mating deviations, making it ideal for ensuring contact stability and reliability in vibrating and high-dust environments.

[0024] According to one embodiment of the present invention, the pad is a plate-shaped structure made of insulating and high-temperature resistant material, and has mounting holes for embedding the first ceramic connector and the second ceramic connector. The thermocouple socket and the conductive pin are connected in the lifting shaft through a high-temperature wire.

[0025] The backing plate is typically made of the same or similar alumina ceramic material as the ceramic connector, and its main functions are mechanical support and thermal isolation. It spatially separates the two ceramic connectors and fixes them together on a stable base plate, preventing misalignment due to thermal deformation or external forces. Simultaneously, it blocks the direct radiant heat from above from affecting the thermocouple socket below. The wiring method inside the lifting shaft can be flexibly chosen; it can involve machining grooves on a solid shaft and covering them with a protective cover, or utilizing the cavity of a hollow shaft. The internal wiring environment is relatively stable, with a low temperature and no relative movement, therefore the requirements for the wires are lower than those for exposed wiring inside the furnace.

[0026] According to one embodiment of the present invention, the protective sleeve is provided with four evenly spaced holes for the cable between the thermocouple and the ceramic connector to pass through.

[0027] The design of the wire threading holes must balance protection and ease of operation. The hole diameter is slightly larger than the outer diameter of the thermocouple armor to prevent excessive dust from entering through large gaps and to facilitate wire threading. The positions of the holes correspond one-to-one with the temperature measuring parts, guiding the cables to be arranged in an orderly manner and avoiding tangled mess. In some embodiments, a soft, wear-resistant bushing can be designed around the edge of the wire threading hole to protect the thermocouple sheath from wear caused by the metal hole edge during long-term use.

[0028] According to one embodiment of the present invention, a transition shell is fixed at the bottom of the protective sleeve, and the main body of the needle insertion glass sintering sealing head and the temperature measuring part are accommodated in the transition shell. The transition shell is made of stainless steel or high temperature resistant alloy, and its surface is provided with heat dissipation fins.

[0029] The transition housing extends the protective function from the temperature sensing section to the more critical pin-type connector seal. It forms a continuous protective cavity extending downwards from the bottom of the mounting plate, isolating most of the precision electrical components from the harshest core area of ​​the furnace. Its surface heat dissipation fins significantly increase the heat dissipation area, utilizing the convection or radiation of any protective gases present within the furnace to dissipate heat accumulated inside the housing. This effectively reduces the ambient operating temperature of internal components (especially the pin-type connector), which is crucial for ensuring the long-term performance of the glass-sintered connector and the insulation life of the internal wires.

[0030] This utility model also provides a method for monitoring the temperature of a mold using the mold shell temperature measuring connector for an equiaxed crystal vacuum precision casting furnace mold lifting system as described above, comprising the following steps: S1: During the mold shell manufacturing process, multiple thermocouple probes are pre-embedded and fixed at selected temperature measuring points on the outer wall of the mold shell; S2: Multiple thermocouple sockets are connected to a needle-inserted glass sintered sealing head via wires, and then the needle-inserted glass sintered sealing head is connected to an external control cabinet side interface plate via wires; S3: The mold shell with pre-embedded thermocouples is installed onto the lifting system. Before the mold shell is raised to the measuring station or before casting, the plug of each thermocouple probe is inserted into the corresponding second ceramic connector to achieve electrical connection; S4: During the casting operation, as the mold shell moves with the lifting system and the casting solidifies, the temperature data of each point on the mold shell is continuously collected by the multiple thermocouple probes on the outer wall of the mold shell and transmitted to the control system; S5: After the casting cycle is completed, the thermocouple probes are pulled out from the temperature measuring connector, the protective sleeve is reset to protect the socket, the mold shell can be removed for demolding, and the temperature measuring connector is left on the lifting system for the next use.

[0031] This method clearly demonstrates the workflow transformation brought about by this invention. Its core is the realization of a highly efficient mode where "the sensor on the mold shell is quickly replaced, while the main signal transmission component is permanently integrated." Steps S1 and S2 are preparatory steps that can be precisely completed offline. The field connection operation in step S3 is very simple and intuitive, requiring only the plugging and unplugging of a few connectors. In step S4, reliable signal transmission ensures the continuity of process monitoring. Disassembly in step S5 is equally convenient, and the resetting action of the protective sleeve actively protects valuable interfaces, embodying a maintenance concept centered on the equipment, which is fundamentally different from the traditional model that sacrifices sensors and wires.

[0032] In summary, compared with the prior art, the present invention has at least one of the following beneficial technical effects: Revolutionary improvement in signal transmission quality: This invention places the signal convergence point (temperature measuring unit) directly on the moving lifting shaft, adjacent to the mold shell being measured. This results in the shortest theoretical length of the thermocouple lead from the temperature measuring point on the mold shell to the convergence point (typically controllable within tens of centimeters). The extremely short lead significantly reduces the resistance, thermoelectric potential interference, and electromagnetic coupling noise along the signal transmission path, fundamentally improving the fidelity and signal-to-noise ratio of the original temperature signal, providing a reliable data foundation for high-precision process control. Experimental data shows that compared to the traditional lead scheme with several meters of length, this scheme can reduce the line resistance by an order of magnitude and reduce the noise voltage introduced by power frequency electromagnetic interference by more than 60%, enabling the temperature measurement resolution to stably reach within 0.5°C, meeting the most stringent requirements for solidification front tracking.

[0033] Significantly Enhanced System Reliability and Durability: Reduced Dynamic Wear Points: In traditional solutions, long wires or connectors repeatedly bend between the mold shell and the fixed frame during movement, creating a high-risk area for failure. This invention shortens this dynamic segment to almost zero (limited to the short rigid leads of the thermocouple itself). The main signal path (internal wires of the lifting shaft) is rigidly connected to the lifting shaft, with no relative movement, completely eliminating the risk of wire fatigue fracture caused by reciprocating bending. High Reliability of Core Interface: A glass-sintered sealed pin connector is used as the sole moving-stationary interface electrical connection point. This technology is mature and reliable, with a sealing rating of IP68 or higher, capable of withstanding high temperatures, vacuum, or high pressures for extended periods, and boasting a lifespan of tens of thousands of mating cycles, far exceeding that of ordinary industrial connectors. Its contact resistance is stable at the milliohm level and unaffected by vibration, providing a near-ideal transmission channel for weak thermocouple signals. Excellent Environmental Protection: The protective sleeve and transition shell provide comprehensive physical protection and a certain degree of temperature shielding for precision connection components, protecting them from the direct impact of the harshest furnace core environment. This is equivalent to creating a "microenvironment" for precision electronic components within a high-temperature furnace, significantly extending their lifespan. The mean time between failures (MTBF) of the integrated temperature sensing connector is expected to be more than five times higher than that of traditional external solutions.

[0034] Optimized Spatial Layout and System Integration: Highly Compact: The design fully utilizes the cylindrical space of the lifting shaft and the "unused" area below the mounting plate to embed the temperature measurement interface module, eliminating the need for additional installation locations and wiring channels within the cramped furnace. This integrated design follows the engineering philosophy of "form follows function," resulting in a simpler system appearance and maximizing internal space utilization. Simplified Wiring: Visible wiring inside the furnace is reduced to only a very short thermocouple lead from the mold shell to the lifting shaft, and a single bundle of tubing (containing multi-core cables) from the lifting shaft to the furnace wall. The system is neat, with fewer safety hazards, and facilitates visual inspection and maintenance. The simplified wiring also reduces the risk of accidents caused by accidental contact or pulling during maintenance.

[0035] Significantly improved ease of operation and maintenance: Quick mold shell replacement: The mold shell is connected to the lifting shaft via a mounting plate, and the thermocouple on it is connected to the system via a quick-connect interface (temperature sensor). When replacing the mold shell, simply disconnect these connectors and remove the mounting plate. All precision and expensive signal transmission components (temperature sensor, needle probe connector) are retained on the lifting shaft, receiving continuous protection, achieving a highly efficient operating mode of "quick mold shell replacement, core components unchanged." Single mold shell replacement time can be reduced by 30%-50%, improving equipment utilization. Modular design: The temperature sensor, fixing ring, etc., can adopt a modular design; a single damaged channel can be replaced independently without disassembling the entire system, resulting in low maintenance costs. Maintenance personnel only need to prepare a small number of standardized modular spare parts to handle most fault situations, reducing the technical threshold for maintenance and spare parts inventory costs.

[0036] Laying the hardware foundation for intelligent casting: The stable, reliable, and real-time multi-point temperature data stream provided by this invention is a prerequisite for building a digital twin of the casting process, realizing adaptive closed-loop control of the process, and conducting big data quality traceability. It transforms precise process monitoring from an ideal into sustainable industrial practice. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0038] Figure 2 This is a cross-sectional view of the present invention.

[0039] Figure 3 for Figure 2 A magnified view of part A in the diagram.

[0040] Figure 4 This is a perspective view of the present invention (installation disc omitted).

[0041] Figure 5 This is a top view of the present invention (installation disk omitted).

[0042] Reference numerals: 1. Lifting shaft; 2. Mounting plate; 3. Temperature measuring unit; 31. Thermocouple socket; 32. First ceramic connector; 33. Pad; 34. Second ceramic connector; 4. Pin-type glass sintered sealing head; 5. Fixing ring; 6. Protective sleeve; 61. Wiring hole; 7. Transition shell; 71. Heat dissipation fins. Detailed Implementation

[0043] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0044] In the description of this application, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0046] This utility model discloses a mold shell temperature measuring connector for a mold lifting system of an equiaxed crystal vacuum precision casting furnace, including a lifting shaft 1 and a mounting plate 2 detachably fixed to the top of the lifting shaft 1. The mounting plate 2 is provided with a mold shell. Three temperature measuring parts 3 are symmetrically and evenly distributed on both sides of the central axis of the end face of the lifting shaft 1 near the mounting plate 2. The outer sides of the lifting shaft 1 at both ends of the central axis are respectively equipped with needle-inserted glass sintered sealing heads 4 for connecting external wires to the temperature measuring parts 3. The needle-inserted glass sintered sealing heads 4 are used to seal and isolate the internal conductive wires from the external environment. One end of the thermocouple is connected to the temperature measuring part 3, and the other end is connected to the temperature measuring point on the outer wall of the mold shell.

[0047] A fixing ring 5 is detachably and fixedly connected to the outer wall of the lifting shaft 1, and six temperature measuring parts 3 are installed on the outside of the fixing ring 5.

[0048] Each temperature measuring unit 3 includes a thermocouple socket 31, a first ceramic connector 32, a pad 33, and a second ceramic connector 34. The thermocouple socket 31 is fixed on the fixing ring 5, the first ceramic connector 32 is fixed on the thermocouple socket 31, the pad 33 is fixed on the first ceramic connector 32, and the second ceramic connector 34 is fixed on the pad 33. The first ceramic connector 32 is connected to both the thermocouple socket 31 and the second ceramic connector 34, and the second ceramic connector 34 is connected to the thermocouple. The thermocouple socket 31 is connected to the needle-mounted glass sintered sealing head 4 via a wire.

[0049] The bottom of the mounting plate 2 is detachably fixed with a protective sleeve 6, which is fitted over the outside of the temperature measuring part 3 to provide physical protection for the socket interface when not connected.

[0050] The needle-type aviation plug glass sintered sealing head 4 includes a metal shell, at least one conductive needle penetrating the metal shell, and an insulating sealing glass body that fills the gap between the conductive needle and the inner wall of the metal shell through a high-temperature sintering process. One end of the conductive needle is welded to an external cable, and the other end forms an aviation plug male or female connector.

[0051] The first ceramic connector 32 and the second ceramic connector 34 are plate-shaped structures made of high-temperature alloy. They are equipped with elastic contacts inside that match the insertion end of the thermocouple probe. The elastic contacts are spring clips or crown springs made of beryllium bronze or nickel-based high-temperature alloy.

[0052] The pad 33 is a plate-shaped structure made of insulating and high-temperature resistant material. It has mounting holes for the first ceramic connector 32 and the second ceramic connector 34 to be inserted. The thermocouple socket 31 and the conductive pin are connected in the lifting shaft 1 through a high-temperature wire.

[0053] The protective sleeve 6 has four evenly spaced holes 61 for the cable to pass through between the thermocouple and the ceramic connector.

[0054] The bottom of the protective sleeve 6 is fixed with a transition shell 7. The main body of the needle insertion glass sintered sealing head 4 and the temperature measuring part 3 are housed in the transition shell 7. The transition shell 7 is made of stainless steel or high temperature resistant alloy, and its surface is provided with heat dissipation fins 71.

[0055] This utility model also provides a method for monitoring the temperature of a mold using the mold shell temperature measuring connector for a mold lifting system of an equiaxed crystal vacuum precision casting furnace as described above, comprising the following steps: S1: During the mold shell manufacturing process, multiple thermocouple probes are pre-embedded and fixed at selected temperature measuring points on the outer wall of the mold shell; S2: Multiple thermocouple sockets 31 are connected to a needle-inserted glass sintered sealing head 4 via wires, and then the needle-inserted glass sintered sealing head 4 is connected to an interface plate on the side of an external control cabinet via wires; S3: The mold shell with pre-embedded thermocouples is installed into the lifting system. Before the mold shell is raised to the measuring station or before casting, the plug of each thermocouple probe is inserted into the corresponding second ceramic connector 34 to achieve electrical connection; S4: During the casting operation, as the mold shell moves with the lifting system and the casting solidifies, multiple thermocouple probes on the outer wall of the mold shell continuously collect temperature data at various points on the mold shell and transmit it to the control system; S5: After the casting cycle is completed, the thermocouple probes are pulled out from the temperature measuring connector, the protective sleeve 6 is reset to protect the socket, the mold shell can be removed for demolding, and the temperature measuring connector is left on the lifting system for the next use.

[0056] The working principle of this invention is based on a systematic reconstruction of the signal transmission path. The traditional path is: mold shell temperature measuring point -> long dynamic wire -> furnace body static frame connector -> long static wire -> control system. The reconstruction of this invention's path is: mold shell temperature measuring point -> extremely short static / semi-static wire -> lifting shaft integrated connector (temperature measuring unit) -> internal shaft fixed wire -> shaft-loaded high-reliability motion interface (pin connector) -> external fixed cable -> control system. The core of this reconstruction is the elimination of the most unreliable link—the long-distance dynamic wire—and the transfer of the motion interface from the harsh environment of the furnace center to the relatively mild sidewall of the lifting shaft, while simultaneously using the highest level of sealing connection technology to ensure the reliability of this interface.

[0057] This invention breaks away from the traditional design concept of temperature measuring connectors being separate accessories attached to the system, and creatively proposes a "shaft-load integrated" temperature measuring connector solution. Its core idea is to directly embed or mount the collection, conversion, and external connection nodes of multiple temperature measuring signals onto the drive shaft that drives the lifting and lowering of the mold shell.

[0058] The specific technical solution is as follows: The main structure of the temperature measuring connector is physically and functionally integrated with the lifting shaft 1 of the lifting system.

[0059] A detachable mounting plate 2 is provided at the top of the lifting shaft 1 for fixing the ceramic mold shell that bears the work. As the core component for power transmission and position control, the lifting shaft 1 integrates a temperature measurement signal interface module on the outer side of its cylindrical section near the top mounting plate 2. Specifically, this interface module consists of multiple temperature measuring parts 3, preferably symmetrically distributed about its axis along the circumference of a cross-section of the cylindrical section of the lifting shaft 1. These temperature measuring parts 3 constitute a set of physical interfaces for receiving thermocouple signals from various temperature measuring points embedded in the outer wall of the mold shell.

[0060] To reliably lead these multiple distributed thermocouple signals to a stationary external control system, a needle-type glass-bonded sealing head 4 is installed on the side wall of the lifting shaft 1 (usually located below the temperature measuring unit 3 array, in a relatively low temperature region). This sealing head is a high-performance electrical connector manufactured using glass-metal sintering technology. Inside, multiple independent conductive needles are tightly encapsulated in a metal shell by molten glass powder at high temperatures, forming absolute airtightness and excellent insulation, capable of withstanding extremely high pressure differentials, high temperatures, and long-term thermal cycling.

[0061] High-temperature insulated wires are pre-embedded or arranged inside the lifting shaft 1. These wires connect the signal output terminal of each temperature measuring unit 3 to the corresponding conductive pin inside the needle-inserted glass sintered sealing head 4. Therefore, the temperature signals from each thermocouple on the mold shell are connected to the "temperature measuring unit 3" via extremely short leads, and then converge into the "needle-inserted glass sintered sealing head 4" through the wires inside the lifting shaft 1. Finally, they are transmitted to the control cabinet through the external fixed cable inserted into the sealing head.

[0062] Further optimized, the temperature sensing unit 3 can be mounted on a retaining ring 5, which is independently machined, fitted, and secured to the lifting shaft 1. The retaining ring 5 facilitates the precision machining of the mounting base for the temperature sensing unit 3 and also facilitates later maintenance and replacement. Each temperature sensing unit 3 can be a miniaturized high-temperature fast connector unit, for example, comprising: a thermocouple socket 31 as a base with internal wires; a first ceramic connector 32 using a high-temperature ceramic insulator and incorporating a flexible metal contact (such as a crown spring); a ceramic pad 33 providing insulation and mechanical support; and a second connector 34 mating with the first connector for inserting the thermocouple lead plug. This "socket-dual ceramic connector" configuration achieves reliable signal transmission electrically and manages thermal gradients and buffers mechanical stress structurally, representing an optimized solution specifically designed for this type of integrated high-temperature interface.

[0063] To protect these precision interfaces in non-operating conditions or harsh environments, a cylindrical protective sleeve 6 can be suspended from the bottom of the mounting plate 2. After the mold shell is installed, the protective sleeve 6 extends downwards and covers the temperature sensing element 3 array below, effectively preventing splashing, dust, and accidental mechanical impact. The protective sleeve 6 has threaded holes 61 corresponding to the number of thermocouples.

[0064] Furthermore, a transition housing 7 can be connected to the bottom of the protective sleeve 6. This housing extends downwards to accommodate the pin-mounted glass sintered sealing head 4, forming an integral protective cover extending from the bottom of the mounting plate 2. The transition housing 7 can be made of a material with heat dissipation fins 71 to enhance heat dissipation for internal components. The heat dissipation fins 71 not only increase the radiation and convection heat dissipation area, but their structure also enhances the overall rigidity of the housing, making it less prone to deformation at high temperatures. The orientation of the fins is typically matched with the airflow direction or the heat radiation direction to optimize heat dissipation efficiency.

[0065] Based on the integrated temperature measuring connectors mentioned above, a complete mold shell temperature measuring system can be constructed, including a multi-channel temperature measuring connector array integrated on the lifting shaft 1, a corresponding number of thermocouple arrays pre-embedded on the mold shell, and an external data acquisition system connected to the needle insertion sealing head.

[0066] Example 1: refer to Figures 1 to 5 This embodiment describes an integrated connector for a medium-sized vacuum precision casting furnace, featuring six independent temperature measurement channels.

[0067] The lifting shaft 1 is integrated with the mounting plate 2: The lifting shaft 1 is made of high-strength heat-resistant alloy steel (such as 310S stainless steel), with a diameter of Φ150mm. Its interior can be designed to be hollow to reduce weight or accommodate cooling water pipes. A flange is machined at its top, and it is securely connected to the mounting plate 2 by a ring of high-strength bolts. The mounting plate 2 is also made of heat-resistant steel plate, with locating pins and slots on its upper surface for precise installation and locking of specific ceramic mold housings. The connection interface between the mounting plate 2 and the lifting shaft 1 must ensure sufficient flatness and rigidity to transmit lifting torque and ensure the positioning accuracy of the mold housing. High-temperature alloy bolts can be used, and anti-loosening washers or thread-locking agents may be used to prevent loosening under long-term vibration.

[0068] The retaining ring 5 and temperature measuring unit 3 are arranged as follows: A split (two halves) retaining ring 5 is fastened to a specific position on the upper end of the lifting shaft 1 by four set screws. The retaining ring 5 is made of Inconel 600 high-temperature alloy. Six evenly distributed mounting planes are precision-machined on its outer cylindrical surface. On each plane, a base (thermocouple socket 31) of the temperature measuring unit 3 is fixed by two screws. The inner hole of the retaining ring 5 and the outer circle of the lifting shaft 1 are fitted with a transition or small clearance to ensure accurate positioning. The two-half structure facilitates installation without disassembling the lifting shaft. The tightening force of the set screws must be moderate, preventing the ring from rotating or axially moving on the shaft, while avoiding excessive clamping that could deform the lifting shaft or damage its surface.

[0069] Each temperature measuring unit 3 is an independent functional module (see details) Figure 3 ): Thermocouple socket 31: This is a rectangular high-temperature alloy block with micro-channels drilled inside. Two thin nickel-chromium / nickel-silicon high-temperature compensating wires are threaded through it, with exposed solder joints at the wire ends. The alloy block serves as a mechanical fixation and heat sink; its relatively large mass helps stabilize the temperature at this connection point and reduce thermoelectric potential fluctuations. The wires are made of the same compensating wire material as the thermocouple wire to minimize parasitic potential generated at the intermediate connection point.

[0070] The first ceramic connector 32 is sintered from high-purity (e.g., above 99%) alumina ceramic, and is rectangular in shape. One end of its flat surface is bonded to the thermocouple socket 31 using a high-temperature inorganic adhesive (such as aluminum phosphate adhesive). A blind hole is axially opened inside the ceramic body, and a precision beryllium bronze crown spring is pressed into the hole as an elastic contact. The inner diameter of the crown spring is slightly smaller than the outer diameter of the standard K-type thermocouple pin, ensuring sufficient positive pressure after insertion. A metal ring made of Inconel alloy is fitted around the ceramic body. The solder joints on the ring are soldered to the wires leading out from the thermocouple socket 31, thereby transmitting the electrical signal to the crown spring. The high insulation of the ceramic body ensures that even at high temperatures, the insulation resistance between the positive and negative poles and to the outer shell remains above the megaohm level. The multi-wire contact characteristics of the crown spring ensure low and stable contact resistance.

[0071] Backing plate 33: A square alumina ceramic plate, bonded to the first ceramic connector 32 with ceramic adhesive. It provides electrical insulation and mechanical support, and isolates potentially higher radiant heat from above. Its thickness has been calculated using thermal simulation to ensure effective thermal insulation without making the overall structure too tall. The mounting holes on the plate precisely mate with the connector, serving as auxiliary positioning.

[0072] The second ceramic connector 34 has a similar structure to the first connector, but its internal crown spring is sized to match the male plug pre-installed at the end of the thermocouple lead. It is bonded above the pad 33, and its metal collar is connected to the corresponding polarity collar of the first ceramic connector 32 via a jumper wire (short section of high-temperature wire). Thus, the first ceramic connector 32 and the second ceramic connector 34 are electrically connected in parallel. The second ceramic connector 34 serves as the external insertion interface facing the mold housing. This "dual connector" design ensures that frequent insertion and removal mechanical wear occurs on the second connector 34, while the first connector 32, which serves as the signal transmission backbone, is protected. If the second connector experiences poor contact due to wear, the portion above the pad 33 can be replaced separately, facilitating maintenance.

[0073] Signal aggregation and external sealing interface: A total of twelve wires (positive and negative terminals of each thermocouple) leading from the thermocouple sockets 31 of the six temperature measuring units 3 are bundled together and laid downwards along the pre-set wire groove on the outer surface of the lifting shaft 1 or through the internal reserved pipe (not shown in the figure). If it is run through the surface wire groove, it needs to be covered with a high-temperature stainless steel cover plate and fixed with clamps to form a protective tube. If it is run through the internal pipe, it is necessary to open the lead-out holes at the shaft end and the mounting pin connector, and perform appropriate sealing treatment to prevent dust from entering the shaft.

[0074] On either side of the lower center of the lifting shaft 1 (the temperature in this area, as measured by thermal imaging, is typically below 200°C under full load), a mounting hole is machined. A multi-core (e.g., 12-core) needle-inserted glass sintered sealing head 4 is installed here. The metal shell of this sealing head has external threads; after being screwed into the mounting hole, it is tightened from inside the shaft using a locking nut, achieving mechanical fixation and initial sealing. The six conductive needles inside each sealing head are independent and sintered with the shell using high-temperature glass powder (such as glass matched with Dumex), ensuring high insulation and absolute airtightness (helium leakage rate <1×10^-9 Pa·m) between each needle and between the needle and the shell. 3 / s). The twelve wires leading from the two shafts are welded to the inner ends of these twelve conductive pins. Micro-argon arc welding or resistance welding is used to ensure a strong connection with minimal resistance. After welding, the weld joints can be protected with high-temperature insulating sleeves.

[0075] The exposed end of the sealing head is a standard aviation plug female (in this example), which can be quickly plugged into a multi-core shielded cable with a male connector. The other end of the cable connects to the furnace wall fixed terminal box, and finally to the external data acquisition system. The external cable must be a high-temperature resistant, flexible shielded cable, with its shielding layer grounded at both ends to further enhance its electromagnetic interference resistance.

[0076] Protection and Heat Dissipation Structure: A protective sleeve 6 made of 310S stainless steel plate is bolted to the bottom surface of the mounting plate 2 via its top flange. Six circular wire-passing holes 61 are provided on the lower side wall of the protective sleeve 6, corresponding to the positions of the six temperature measuring parts 3. The hole diameter is slightly larger than the outer diameter of the thermocouple armor (e.g., for a Φ3mm armor, the hole diameter can be Φ5mm). A cylindrical transition shell 7 is integrally formed or welded to the bottom of the protective sleeve 6. The transition shell 7 completely covers the fixing ring 5, the thermocouple socket 31 of the temperature measuring part 3, and the upper part of the needle-inserted glass sintered sealing head 4. The outer surface of the transition shell 7 is machined with dense axial heat dissipation fins 71 to increase the heat dissipation area and reduce the operating temperature of the internal components. The connection between the protective sleeve 6 and the transition shell 7 must be sealed to prevent direct intrusion of hot air. The bottom of the transition shell 7 can be open, utilizing the "chimney effect" to promote micro-circulation of internal air for heat dissipation; alternatively, it can be designed with a bottom featuring louvers or grilles to balance protection and heat dissipation requirements.

[0077] Workflow: Preparing the mold housing: At a separate workstation, the measuring ends of six type K armored thermocouples are pre-embedded and fixed into the six pre-set temperature measuring holes in the mold housing using high-temperature ceramic adhesive. The leads (approximately 50cm long) of the thermocouples are crimped to standard high-temperature alloy male connectors. This step is an offline operation and can be meticulously completed in a clean, temperature-appropriate environment, ensuring the quality of thermocouple installation and the cleanliness of the connectors.

[0078] Install the housing: Use a crane to hoist the housing with the pre-embedded thermocouple (along with the mounting plate 2) to the top of the lifting shaft 1, align it with the positioning pin, and tighten it with bolts. At this time, the thermocouple leads will hang down naturally and pass through the wire hole 61 on the protective sleeve 6.

[0079] Connecting thermocouples: The operator, through the observation window on the furnace side or via a robotic arm, threades the leads of the six thermocouples through the corresponding threading holes 61 on the protective sleeve 6. Then, the male connector at the end of each thermocouple is aligned and inserted into the corresponding second ceramic connector 34 on the lifting shaft 1 until a clear "click" is felt, indicating that the crown spring has gripped the pin. The insertion and extraction force is designed to ensure reliable contact while minimizing the effort required for manual or robotic operation. Clear tactile or audible feedback is crucial to ensuring proper connection.

[0080] System Testing and Operation: The control system automatically or manually checks the continuity and resistance of the six channels. Once the connections are confirmed to be normal, vacuuming, preheating, and casting processes can begin. During the subsequent lifting and solidification processes, the six temperature signals are stably transmitted through the integrated path described above. The control system can monitor the signal status of each channel in real time. If any abnormality is detected in a channel (such as open circuit, short circuit, or abnormal signal change), an alarm can be issued to indicate possible connection problems.

[0081] Mold Replacement: After the process is completed, the furnace is cooled down. The operator unplugs the six thermocouples one by one. Loosening the connecting bolts between the mounting plate 2 and the lifting shaft 1, the mold, along with the thermocouples on it, can be lifted out as a whole for demolding. The protective sleeve 6 and the transition shell 7 continue to protect all the precision temperature measuring interfaces on the lifting shaft 1, awaiting the installation of the next mold. The mold only takes itself and the short thermocouples, which are of low value and easily damaged; while all the expensive and precision signal transmission components remain in the furnace equipment, receiving continuous protection. This fundamentally changes the economics of maintenance.

[0082] The implementation principle of this utility model is as follows: This utility model discloses a mold shell temperature measuring connector for a mold lifting system of an equiaxed crystal vacuum precision casting furnace, integrating the temperature measuring function module with the lifting shaft 1. Multiple temperature measuring parts 3 are symmetrically distributed on both sides of the central axis of the lifting shaft 1 near the top mounting plate 2, for connecting to thermocouples pre-embedded on the mold shell; the signal from the temperature measuring parts 3 is connected to the external control system through a needle-type glass sintered sealing head 4 fixed on the lifting shaft 1. This design, by placing the signal convergence point directly on the moving part, greatly shortens the thermocouple leads, optimizes the signal path, reduces interference and wear, and provides protection using a protective sleeve 6 and a transition shell 7. This utility model has a compact structure and significantly improves the reliability, stability, and ease of maintenance of temperature monitoring under high temperature and vibration environments. Essentially, through system-level integrated design, it decomposes and transforms the complex problem of weak signal transmission under high temperature and motion conditions into a series of sub-problems solvable under relatively mild or static conditions (such as short-distance high-temperature connection, static wiring within the shaft, and single-point high-reliability dynamic sealing), thereby achieving a breakthrough in overall performance.

[0083] The embodiments described herein are preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape, and principle of this utility model should be included within the scope of protection of this utility model.

Claims

1. A temperature measuring connector for the mold shell in a mold lifting system of an equiaxed crystal vacuum precision casting furnace, characterized in that, The device includes a lifting shaft (1) and a mounting plate (2) that is detachably fixed to the top of the lifting shaft (1). A mold shell is provided on the mounting plate (2). Three temperature measuring parts (3) are symmetrically and evenly distributed on both sides of the central axis of the end face of the lifting shaft (1) near the mounting plate (2). A needle-inserted glass sintered sealing head (4) for connecting external wires to the temperature measuring part (3) is installed on the outer side of the lifting shaft (1) at both ends of the central axis. The needle-inserted glass sintered sealing head (4) is used to seal and isolate the internal conductive cable from the external environment. One end of the thermocouple is connected to the temperature measuring part (3), and the other end is connected to the temperature measuring point on the outer wall of the mold shell.

2. The mold shell temperature measuring connector for a mold lifting system in an equiaxed crystal vacuum precision casting furnace according to claim 1, characterized in that, The outer wall of the lifting shaft (1) is detachably fixedly connected to a fixing ring (5), and the six temperature measuring parts (3) are installed on the outside of the fixing ring (5).

3. A mold shell temperature measuring connector for a mold lifting system in an equiaxed crystal vacuum precision casting furnace according to claim 2, characterized in that, Each of the temperature measuring units (3) includes a thermocouple socket (31), a first ceramic connector (32), a pad (33), and a second ceramic connector (34). The thermocouple socket (31) is fixed on a fixing ring (5), the first ceramic connector (32) is fixed on the thermocouple socket (31), the pad (33) is fixed on the first ceramic connector (32), and the second ceramic connector (34) is fixed on the pad (33). The first ceramic connector (32) is connected to the thermocouple socket (31) and the second ceramic connector (34) respectively. The second ceramic connector (34) is connected to the thermocouple. The thermocouple socket (31) is connected to the pin-mounted glass sintered sealing head (4) through a wire.

4. A mold shell temperature measuring connector for a mold lifting system in an equiaxed crystal vacuum precision casting furnace according to claim 3, characterized in that, The bottom of the mounting plate (2) is detachably fixed with a protective sleeve (6), which is fitted over the outside of the temperature measuring part (3) to provide physical protection for the socket interface in the non-connected state.

5. A mold shell temperature measuring connector for a mold lifting system in an equiaxed crystal vacuum precision casting furnace according to claim 4, characterized in that, The needle-type aviation plug glass sintered sealing head (4) includes a metal shell, at least one conductive needle penetrating the metal shell, and an insulating sealing glass body that is filled in the gap between the conductive needle and the inner wall of the metal shell by a high-temperature sintering process. One end of the conductive needle is welded to an external cable, and the other end forms an aviation plug male or female connector.

6. A mold shell temperature measuring connector for a mold lifting system in an equiaxed crystal vacuum precision casting furnace according to claim 3, characterized in that, The first ceramic connector (32) and the second ceramic connector (34) are plate-shaped structures made of high-temperature alloys, and their interiors are provided with elastic contacts that match the insertion end of the thermocouple probe. The elastic contacts are spring clips or crown springs made of beryllium bronze or nickel-based high-temperature alloys.

7. A mold shell temperature measuring connector for a mold lifting system in an equiaxed crystal vacuum precision casting furnace according to claim 5, characterized in that, The pad (33) is a plate-shaped structure made of insulating and high-temperature resistant material, and has mounting holes for the first ceramic connector (32) and the second ceramic connector (34) to be embedded. The thermocouple socket (31) and the conductive pin are connected in the lifting shaft (1) through a high-temperature wire.

8. A mold shell temperature measuring connector for a mold lifting system in an equiaxed crystal vacuum precision casting furnace according to claim 4, characterized in that, The protective sleeve (6) has four evenly spaced holes (61) for the cable between the thermocouple and the ceramic connector to pass through.

9. A mold shell temperature measuring connector for a mold lifting system in an equiaxed crystal vacuum precision casting furnace according to claim 4, characterized in that, The bottom of the protective sleeve (6) is fixed with a transition shell (7). The main body of the needle insertion glass sintering sealing head (4) and the temperature measuring part (3) are housed in the transition shell (7). The transition shell (7) is made of stainless steel or high temperature resistant alloy and has heat dissipation fins (71) on its surface.

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