A four-electrode conductivity sensor for liquid cooling and its measurement method

Abstract

This invention discloses a liquid-cooled four-electrode conductivity sensor and its measurement method, relating to the field of sensor technology. The sensor includes an insulating body and four probes fixedly disposed within the insulating body. The measuring end of the insulating body has a side plane parallel to its axial direction, and the sides of the four probes are exposed on the side plane to form measuring electrodes, which contact the liquid being measured. This invention sets the measuring end of the insulating body to a side plane parallel to the axial direction, exposing the probe sides to form a "side-type measurement" structure. Combined with the flow channel formed by the protective sleeve, when the liquid flows through, the fluid generates a parallel scouring effect along the side plane, completely eliminating the dead angles that traditional end-face electrodes obstruct for fluid and air bubbles.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a liquid-cooled four-electrode conductivity sensor and its measurement method. Background Technology

[0002] With the rapid development of industrial liquid cooling technology, monitoring the conductivity of coolant has become a key indicator for ensuring the safe and stable operation of the system. Current conductivity measurement devices typically consist of two parts: an instrument and analog conductivity electrodes. The instrument is further divided into three main modules: a display LCD screen, data acquisition, and data transmission. The analog conductivity electrodes at the front end are connected to the instrument via data leads and pin connectors or other connectors.

[0003] However, existing technologies have the following obvious drawbacks in practical applications: 1. Low accuracy due to air bubble adhesion: Existing conductivity sensors typically place multiple electrodes on the same end face (i.e., end face measurement). During detection, air bubbles in the fluid are easily blocked and become stuck on the end face where the electrodes are located, unable to escape. The accumulation of air bubbles can significantly change the dielectric constant and contact area between the plates, causing fluctuations in the measurement data and severely affecting the detection accuracy.

[0004] 2. Poor polarization and anti-contamination capabilities: In traditional two-electrode designs, polarization (i.e., polarization voltage drop) easily occurs on the electrode surface during measurement, and the electrodes are easily contaminated in complex liquid-cooled environments, resulting in low long-term measurement accuracy.

[0005] 3. Large size and inconvenient installation: Traditional analog conductivity sensors must be connected to external instruments or transmitters to transmit data to a computer or control system. This combination increases hardware costs, and the instruments and transmitters occupy a large space, making them extremely inconvenient to install in compact liquid-cooled equipment. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a liquid-cooled four-electrode conductivity sensor and its measurement method.

[0007] To solve the above technical problems, the technical solution of the present invention is as follows: On one hand, the present invention provides a liquid-cooled four-electrode conductivity sensor, including an insulating body and four probes fixedly disposed within the insulating body; the measuring end of the insulating body is provided with a side plane parallel to its axial direction, and the sides of the four probes are exposed on the side plane to form measuring electrodes, and the sides of the measuring electrodes are in contact with the liquid to be measured.

[0008] The above technical solution adopts a side-type measurement structure, with the measuring electrode located on the side of the sensor rather than the end face. When the sensor is installed vertically, the bubble will naturally float upwards and will not stay on the surface of the measuring electrode, effectively solving the problem of the bubble sticking to the electrode end face and being unable to be discharged, thus significantly improving the measurement accuracy.

[0009] On the other hand, the present invention also provides a measurement method for a liquid-cooled four-electrode conductivity sensor, comprising the following steps: The liquid-cooled four-electrode conductivity sensor is placed in the liquid to be measured with its axis in a vertical position, so that the measuring end of the insulating body is completely immersed in the liquid to be measured. Keep the sensor in a vertical position and collect the conductivity signal of the liquid to be tested through the measuring electrodes.

[0010] The beneficial effects of this invention are: (1) In this invention, the measuring end of the insulating body is set as a side plane parallel to the axial direction, so that the side of the probe is exposed to form a "side measurement" structure. With the flow channel formed by the protective sleeve, when the liquid flows through, the fluid will generate a parallel flushing effect along the side plane, which completely eliminates the dead angle of obstruction of fluid and air bubbles by the traditional end face electrode. Especially in the vertically placed measurement method, the air bubbles rise naturally along the side plane and are discharged under the action of buoyancy, which greatly improves the measurement accuracy and data stability of conductivity.

[0011] (2) The guide slope provided at the end of the side plane in this invention plays a seamless guiding role. When the upward-climbing bubble reaches the top, it will be smoothly guided to the outside of the insulating body along the slope, completely eliminating the dead angle of stagnation that is easily formed by right-angle steps. This dual exhaust mechanism minimizes the interference of bubbles on the measurement, greatly improving the measurement accuracy and data stability of conductivity.

[0012] (3) The present invention adopts a four-probe design to separate the "driving electrode" that provides constant alternating current from the "measuring electrode" that measures the voltage difference in the physical circuit. Almost no current flows through the inner measuring electrode, thereby fundamentally eliminating the polarization voltage drop on the electrode surface, possessing extremely strong anti-contamination ability, and ensuring stable long-term measurement output.

[0013] (4) This invention is designed for special working conditions in the liquid cooling industry. The insulating body is made of PEEK material and the probe is made of 316L stainless steel. The above materials give the sensor excellent high temperature resistance and corrosion resistance, and it can work stably in complex coolant for a long time without material degradation.

[0014] (5) The present invention integrates the data processing module directly into the hollow metal shell of the sensor. The sensor can complete the accurate conversion of analog signals to digital signals on-site, without the need for a bulky external display instrument or transmitter. This integrated design greatly reduces the size and installation space requirements, and the digital signal output has strong anti-interference ability, making it directly compatible with modern liquid-cooled centralized control systems. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic diagram of the structure of the liquid-cooled four-electrode conductivity sensor provided by the present invention; Figure 2 A bottom view of the liquid-cooled four-electrode conductivity sensor provided by the present invention; Figure 3 A cross-sectional schematic diagram of the liquid-cooled four-electrode conductivity sensor provided by the present invention; Figure 4 A schematic diagram of the insulating body in the liquid-cooled four-electrode conductivity sensor provided by the present invention; The components include: 1. Insulating body; 2. Probe; 3. Side plane; 4. Protective sleeve; 5. Liquid passage hole; 6. Through hole; 7. Flow guide slope; 8. Metal shell. Detailed Implementation

[0017] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0018] Example 1: As Figure 1 As shown, this embodiment provides a liquid-cooled four-electrode conductivity sensor, which mainly consists of an insulating body 1, four probes 2, a protective sleeve 4, a hollow metal shell 8, and a built-in data processing module.

[0019] Specifically, the interior of the insulating body 1 has four cylindrical through holes 6 pre-machined at equal intervals parallel to each other along its axial direction (i.e., the longitudinal direction of the sensor). Four cylindrical probes 2 are tightly and fixedly inserted into these four through holes 6, ensuring a complete seal of the internal structure. The measuring end of the insulating body 1 is not a conventional complete cylinder, but rather a side plane 3 parallel to its axial direction is formed by a vertical cutting process. The cutting depth of this side plane 3 precisely cuts into the four through holes 6. This intersecting structure allows one side wall of each of the four through holes 6 to be partially open.

[0020] Correspondingly, the side arcs of the four cylindrical probes 2 inserted into the hole are also simultaneously opened, thus exposing them on the side plane 3, forming measuring electrodes for detecting fluid conductivity. Since the cut or shaped surfaces are absolutely parallel, the surfaces of the probes 2 exposed on the side plane 3 are standard rectangular planes, and these rectangular surfaces are on the same absolute horizontal plane as the side plane 3 of the measuring end of the insulating body 1, achieving a perfectly "flush" state. This "side-type measuring structure," devoid of any microscopic protrusions or recesses, provides the fluid with an extremely smooth scouring surface, completely destroying the physical basis for bubble adhesion and retention.

[0021] Meanwhile, in terms of electrical principle, the four probes 2 constitute a standard four-electrode anti-polarization architecture: the two outer probes 2 act as "driving electrodes," responsible for injecting a constant alternating current into the fluid; the two inner probes 2 act as "measuring electrodes," specifically used to measure the voltage drop between two points in the fluid. Due to the extremely high input impedance of the measurement circuit, almost no current flows through the inner measuring electrodes, thus fundamentally eliminating the polarization voltage drop at the inner electrode interface and ensuring high accuracy and long-term stability of the full-range measurement data.

[0022] In this embodiment, the insulating body 1 is made of PEEK (polyetheretherketone) material, which is resistant to high temperatures and chemical corrosion, to withstand long-term immersion in complex liquid cooling media. All four probes 2 are made of 316L stainless steel to ensure high conductivity and excellent corrosion resistance.

[0023] like Figure 2 and Figure 3 As shown, a hollow cylindrical protective sleeve 4 is coaxially fitted outside the measuring end of the insulating body 1. The inner wall of the protective sleeve 4 and the outer wall of the measuring end of the insulating body 1 naturally enclose a relatively independent internal measuring cavity. The aforementioned side plane 3 with four probes 2 is located within this measuring cavity.

[0024] Multiple through-holes 5 are evenly distributed on the cylindrical sidewall of the protective sleeve 4, connecting the internal measuring chamber to the liquid to be measured in the external pipeline. In actual operation, the external liquid to be measured flows naturally through the through-holes 5 and fills the entire measuring chamber, completely enveloping the internal side plane 3 and the electrodes. The protective sleeve 4 not only protects against external impacts, but more importantly, it successfully isolates a relatively stable local measuring environment with better laminar flow in the main flow channel of the pipeline, where flow velocity varies and turbulence is complex. This avoids direct impact and signal interference from severe fluid disturbances on the side electrodes.

[0025] In addition, this embodiment also provides a flow guiding slope 7 at the end of the measuring end side plane 3 of the insulating body 1 (i.e., at the boundary of the measurement). One end of the flow guiding slope 7 is seamlessly and smoothly connected to the flat side plane 3, while the other end extends radially towards the cylindrical outer wall of the insulating body 1, forming a gradually changing "ramp". In terms of fluid dynamics, this slope constitutes a bubble guiding surface. When the fluid flows along the side plane 3, the accompanying microbubbles are no longer blocked by the right-angle step after reaching the end, but are gently guided to the outer arc space of the insulating body 1 along the inclination angle of the slope, and then quickly discharged from the measuring chamber through the liquid passage 5 above.

[0026] Combination Figure 3 As can be seen from the cross-sectional view, the components of this sensor are connected by a threaded sealing method. The non-measuring end of the insulating body 1 is machined with external threads, which are screwed into the internal threads at the end of the hollow metal shell 8 in a fixed and sealing manner. At the same time, a sealing ring (O-ring) is pressed between the mating surfaces of the two ends to achieve a high level of waterproofing for the internal circuit chamber. The top of the protective sleeve 4 has internal threads, which are screwed directly onto the external threads at the end of the metal shell 8. The outer wall surface of the middle part of the metal shell 8 is also provided with a large-sized mounting external thread to facilitate the screwing of the entire sensor onto the liquid cooling pipe or equipment interface.

[0027] A data processing module is installed inside the cavity of the metal casing 8. The tail ends of the four probes 2 extend towards the non-measuring end and are electrically connected to the data processing module. This built-in data processing module can convert the weak analog signals collected by the probes 2 into highly interference-resistant digital signals (such as RS485) on-site, and output them directly to external control equipment through a cable interface, completely eliminating the need for bulky external transmitter instruments and greatly saving installation space.

[0028] Example 2: This example provides a measurement method for a liquid-cooled four-electrode conductivity sensor, the operation steps of which are as follows: Step S1: Place the liquid-cooled four-electrode conductivity sensor into the liquid to be tested with its axis in a vertical position, so that the measuring end of the insulating body is completely immersed in the liquid to be tested; Step S2: Keep the sensor in a vertical position and collect the conductivity signal of the liquid to be tested through the measuring electrode.

[0029] Under this operating condition, the side plane is parallel to the direction of gravity, and the fluid channel within the measuring chamber is also vertical. When air bubbles are mixed in the fluid, the bubbles, under the combined effect of their own buoyancy and the liquid flow, will only smoothly move upwards along the vertical side plane. When the bubbles climb to the top of the side plane, they will seamlessly connect to the guide slope, and be smoothly guided to the outside of the insulating body along the slope angle, and finally escape from the flow hole above the protective sleeve. The above-mentioned dual venting mechanism of "side plane flushing + sloped exit" combined with the vertical installation method achieves zero dead angle self-expulsion of bubbles, ensuring the ultimate stability of the measurement.

[0030] In addition to the above embodiments, the present invention may have other implementation methods; all technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A liquid-cooled four-electrode conductivity sensor, characterized in that, It includes an insulating body (1) and four probes (2) fixedly disposed within the insulating body (1); The measuring end of the insulating body (1) is provided with a side plane (3) parallel to its axis. The sides of the four probes (2) are exposed on the side plane (3) to form measuring electrodes. The sides of the measuring electrodes are in contact with the liquid to be measured.

2. The liquid-cooled four-electrode conductivity sensor according to claim 1, characterized in that, The measuring end of the insulating body (1) is covered with a protective sleeve (4). The inner wall of the protective sleeve (4) and the outer wall of the measuring end of the insulating body (1) form a measuring cavity. The side plane (3) is located inside the measuring cavity. The protective sleeve (4) is provided with a liquid passage hole (5) that communicates with the measuring cavity.

3. The liquid-cooled four-electrode conductivity sensor according to claim 1, characterized in that, The insulating body (1) has four through holes (6) arranged in parallel along the axial direction, and the four probes (2) are respectively fixedly inserted into the four through holes (6); The probe (2) has a cylindrical structure. The side plane (3) intersects with the four through holes (6), so that the surfaces of the four probes (2) exposed on the side plane (3) are all rectangular planes, and the rectangular planes are flush with the side plane (3).

4. The liquid-cooled four-electrode conductivity sensor according to claim 1, characterized in that, The measuring end of the insulating body (1) is also provided with a flow guiding slope (7), which is connected to the end of the side plane (3) and extends obliquely from the side plane (3) toward the outer wall of the insulating body (1) to form a bubble guiding surface.

5. The liquid-cooled four-electrode conductivity sensor according to claim 2, characterized in that, It also includes a hollow metal shell (8), the non-measuring end of the insulating body (1) is fixed and sealed inside the metal shell (8), and the outer wall surface of the metal shell (8) is provided with external threads for installation.

6. The liquid-cooled four-electrode conductivity sensor according to claim 5, characterized in that, The non-measuring end of the insulating body (1) is threadedly connected to the end of the metal shell (8), and a sealing ring is provided between the non-measuring end of the insulating body (1) and the end of the metal shell (8), and the protective sleeve (4) is threadedly connected to the metal shell (8).

7. The liquid-cooled four-electrode conductivity sensor according to claim 5, characterized in that, The metal casing (8) contains a data processing module, which is electrically connected to the probe (2) and is used to convert the analog signals collected by the probe (2) into digital signals and output them through the data transmission interface.

8. The liquid-cooled four-electrode conductivity sensor according to claim 1, characterized in that, The probe (2) is made of 316L stainless steel.

9. The liquid-cooled four-electrode conductivity sensor according to claim 1, characterized in that, The insulating body (1) is made of PEEK.

10. A method for measuring the conductivity of a liquid-cooled four-electrode sensor as described in any one of claims 1 to 9, characterized in that, Includes the following steps: The liquid-cooled four-electrode conductivity sensor is placed in the liquid to be tested with its axis in a vertical position, so that the measuring end of the insulating body is completely immersed in the liquid to be tested; The sensor is kept in the vertical position, and the conductivity signal of the liquid to be tested is acquired through the measuring electrode.

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