A steel shot flow detection sensor for high-pressure water jet sand supply pipe

Abstract

The present invention discloses a steel shot flow detection sensor for a high-pressure water jet sand supply pipe. The sensor comprises: a coil induction component, a signal generating circuit, and a signal conditioning circuit, wherein the signal generating circuit is connected to the induction coil and the signal conditioning circuit, respectively. The coil induction component is mounted on the sand supply pipe and is used to sense changes in the steel shot flow rate within the sand supply pipe and convert the changes in the steel shot flow rate into changes in the magnetic medium, thereby causing changes in the inductive reactance of the coil within the coil induction component. The signal generating circuit is used to capture the changes in the inductive reactance of the coil induction component and convert the changes in the inductive reactance into a detection signal whose frequency varies with the inductive reactance. The signal conditioning circuit is used to convert the detection signal into an output voltage whose magnitude varies with the concentration of the steel shot. Compared with the prior art, the present invention can achieve non-destructive detection of the steel shot flow rate within the sand supply pipe by sensing changes in the steel shot flow rate within the sand supply pipe through the coil induction component mounted on the sand supply pipe.

Description

Technical Field

[0001] The invention relates to the field of metal surface cleaning, in particular to a steel shot flow detection sensor for a high-pressure water jet sand supply pipe. Background Art

[0002] Abrasive high-pressure water jetting uses a mixture of high-pressure water and steel shot to clean and remove impurities from metal surfaces. It is a new, purely physical, environmentally friendly metal surface cleaning technology. The steel shot is supplied through a sand supply hose, which is made of a non-metallic material. The high-pressure water jet system has strict requirements on the steel shot content in the mixture. When the steel shot concentration is reduced, the surface cleaning quality will be reduced. In addition, the sand supply pipe may be blocked by steel shot, which will cause the cleaning quality to be seriously unqualified. Therefore, the steel shot flow rate of the sand supply pipe must be monitored in real time (see Figure 1 Due to the process requirements of the high-pressure water jet system, the detection of the metal flow in the sand supply hose must meet many conditions, such as being able to adapt to different types of metal steel shots, adapting to different hose diameters, not opening holes in the hose, not damaging the hose structure, and not adding new joints. Commonly used flow detection methods and devices are unable to detect the flow of steel shots in the sand supply hose, and it is necessary to develop a detection device to address these issues. Summary of the Invention

[0003] The present invention provides a steel shot flow detection sensor for a high-pressure water jet sand supply pipe, which is used to solve the technical problem that the existing flow detection method cannot perform flow detection on the steel shots of the sand supply hose.

[0004] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0005] A steel shot flow detection sensor for a high-pressure water jet sand supply pipe comprises: a coil induction component, a signal generating circuit and a signal conditioning circuit, wherein the signal generating circuit is connected to the induction coil and the signal conditioning circuit respectively;

[0006] The coil induction component is sleeved on the sand supply pipe, and is used to sense the flow change of the steel shot in the sand supply pipe and convert the flow change of the steel shot in the sand supply pipe into its own inductive reactance change;

[0007] The signal generating circuit is used to capture the inductive reactance change of the coil inductive component and convert the inductive reactance change into a detection signal whose frequency changes with the inductive reactance;

[0008] The signal conditioning circuit is used to convert the detection signal into an output voltage whose magnitude varies with the concentration of the steel shot;

[0009] Preferably, the coil induction assembly includes a coil skeleton and a coil; the coil skeleton is a hollow tube for being sleeved on the sand supply pipe; the coil is wound around the outer surface of the coil skeleton and connected to a signal generating circuit.

[0010] Preferably, the signal generating circuit includes: an operational amplifier U1, a capacitor C1, a capacitor C2, a resistor R3, a resistor R4, and a resistor R5; the non-inverting input terminal of the operational amplifier is connected to the first end of the resistor R3, the second end of the resistor R3 is grounded, and the second end of the resistor R3 is also connected to the first end of the capacitor C1, the second end of the capacitor C1 is connected to the output end of the operational amplifier U1, the inverting input terminal of the operational amplifier U1 is connected to its output end through the resistor R5, the inverting input terminal of the operational amplifier U1 is also connected to the first end of the resistor R4, the second end of the resistor R4 is respectively connected to the first end of the coil and the first end of the capacitor C2, and the second end of the coil is connected to the output end of the operational amplifier U1; the second end of the capacitor C2 is also connected to the first end of the capacitor C1.

[0011] Preferably, the signal conditioning circuit includes: a waveform conversion circuit, a voltage conversion circuit, a frequency conversion circuit, and a voltage-frequency conversion circuit; the signal generating circuit, the waveform conversion circuit, the voltage conversion circuit, the frequency conversion circuit, and the voltage-frequency conversion circuit are connected in sequence;

[0012] The waveform conversion circuit is used to perform high-frequency filtering on the detection signal and convert the filtered detection signal into a pulse signal;

[0013] The voltage conversion circuit is used to convert the pulse signal into a standard level pulse signal;

[0014] The frequency conversion circuit is used to perform frequency reduction processing on the standard level pulse signal;

[0015] The voltage-frequency conversion circuit is used to convert the standard level pulse signal after the frequency reduction process into an output voltage whose magnitude varies with the concentration of the steel shot.

[0016] Preferably, the waveform conversion circuit includes: an operational amplifier U8, a resistor R7, a capacitor C10 and a capacitor C11; the non-inverting input terminal of the operational amplifier U8 is connected to the output terminal of the operational amplifier U1, the inverting input terminal of the operational amplifier U8 is grounded together with the EMIT / OUT terminal, the inverting input terminal of the operational amplifier U8 is also connected to its VCC- terminal through the capacitor C10, and the VCC- terminal of the operational amplifier U8 is also connected to the negative power supply voltage terminal; the output terminal of the operational amplifier U8 is connected to the first terminal of the resistor R7, the second terminal of the resistor R7 and the VCC+ terminal of the operational amplifier U8 are connected to the positive power supply voltage terminal, and the positive power supply voltage terminal is also grounded through the capacitor C11.

[0017] Preferably, the voltage conversion circuit includes an operational amplifier U5, an operational amplifier U6, a resistor R1, a resistor R2, a resistor R6, a resistor R14, a resistor R15 and a resistor R16; the inverting input terminal of the operational amplifier U5 is connected to the output terminal of the operational amplifier U8 through the resistor R16, the inverting input terminal of the operational amplifier U5 is also connected to its input terminal through the resistor R6, the non-inverting input terminal of the operational amplifier U5 is grounded through the resistor R2, the output terminal of the operational amplifier U5 is connected to the inverting input terminal of the operational amplifier U6 through the resistor R14, the inverting input terminal of the operational amplifier U6 is also connected to its output terminal through the resistor R15, the non-inverting input terminal of the operational amplifier U6 is grounded through the resistor R1, and the output terminal of the operational amplifier U6 is also connected to the input terminal of the frequency conversion circuit.

[0018] Preferably, the frequency conversion circuit is an integrated D flip-flop, the PRSET terminal and the CLR terminal of the integrated D flip-flop are short-circuited to a high level, and the Q# terminal and the D terminal of the integrated D flip-flop are short-circuited; the CK terminal of the integrated D flip-flop is connected to the output terminal of the operational amplifier U6, and the Q terminal of the integrated D flip-flop is connected to the input terminal of the voltage-frequency conversion circuit.

[0019] Preferably, the voltage-frequency conversion circuit includes: an integrated voltage-frequency chip U7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor RT, a resistor RL, a sliding rheostat R13, a capacitor C9, a capacitor C12 and a capacitor CT;

[0020] The THR terminal of the integrated voltage-frequency chip U7 is connected to the Q terminal of the integrated D flip-flop through the capacitor C12, and the THR terminal of the integrated voltage-frequency chip U7 is also connected to the positive power supply voltage terminal through the resistor R8. The R / C terminal of the integrated voltage-frequency chip U7 is connected to the first terminal of the capacitor CT, and the second terminal of the capacitor CT is grounded together with the GND terminal and the FREQ OUT terminal of the integrated voltage-frequency chip U7. The R / C terminal of the integrated voltage-frequency chip U7 is also connected to the positive power supply voltage terminal through the resistor RT, and the COMP IN terminal of the integrated voltage-frequency chip U7 is also connected to the positive power supply voltage terminal through the resistor R9. The COMP IN terminal of the integrated voltage-frequency chip U7 is also grounded through the resistor R10. The VS terminal of the integrated voltage-frequency chip U7 is connected to the positive power supply voltage terminal, and the REF The I terminal is connected to the first end of the sliding rheostat R13 through the resistor R11, the second end of the sliding rheostat R13 is grounded, and the second end of the sliding rheostat R13 is also connected to the first end of the capacitor C9 and the first end of the resistor RL respectively. The second end of the capacitor C9 and the second end of the resistor RL are both connected to the I OUT terminal of the integrated voltage-frequency chip U7, and the second end of the resistor RL serves as the output end of the voltage-frequency conversion circuit.

[0021] Preferably, the models of the operational amplifier U1, operational amplifier U5, and operational amplifier U6 are all UA741CP, the model of the operational amplifier U8 is LM311DR, and the model of the integrated D flip-flop is XD74LS74; the model of the integrated voltage-frequency chip U7 is LM331N; the coil skeleton is a PVC tube with an adjustable inner hole diameter, and the coil is a single-layer coil wound with enameled wire.

[0022] Preferably, the parameters of the coil are determined according to the following formula:

[0023]

[0024]

[0025]

[0026] Among them, N is the number of turns required; LEN is the winding length of the coil; L is the inductance of the coil; A is the outer cross-sectional area of ​​the frame, is the capacitance value of capacitor C1, is the capacitance value of capacitor C2.

[0027] The present invention has the following beneficial effects:

[0028] 1. The steel shot flow detection sensor for a high-pressure water jet sand supply pipe of the present invention comprises: a coil induction component, a signal generating circuit, and a signal conditioning circuit, the signal generating circuit being connected to the induction coil and the signal conditioning circuit, respectively. The coil induction component is mounted on the sand supply pipe and is used to sense changes in the steel shot flow rate within the sand supply pipe and convert the changes in the steel shot flow rate into changes in the magnetic medium, thereby causing changes in the inductive reactance of the coil within the coil induction component. The signal generating circuit is used to capture changes in the inductive reactance of the coil induction component and convert the changes in the inductive reactance into a detection signal whose frequency varies with the inductive reactance. The signal conditioning circuit is used to convert the detection signal into an output voltage whose magnitude varies with the steel shot concentration. Compared to the prior art, the present invention can achieve non-destructive detection of the steel shot flow rate within the sand supply pipe by sensing changes in the steel shot flow rate within the sand supply pipe through the coil induction component mounted on the sand supply pipe.

[0029] 2. In the preferred embodiment, a frequency conversion circuit is added to the present invention to prevent the sensor from saturation.

[0030] 3. In the preferred embodiment, the coil skeleton of the present invention has a variable diameter and can adapt to sand supply hoses of different diameters; it is suitable for testing different types of steel shots and metal abrasives; there are no requirements for the pressure level of the pipeline; there are no requirements for the shape and direction of the pipeline; there is no need to destroy the original pipeline structure; no need to add new pipeline joints; it is very easy to install and can be directly put on the tested pipe body without the need for fixed installation.

[0031] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 It is a structural diagram of a high-pressure water jet sand supply pipe in the prior art;

[0034] Figure 2 This is a circuit diagram of a steel shot flow detection sensor for a high-pressure water jet sand supply pipe in a preferred embodiment of the present invention;

[0035] Figure 3 is the output characteristic curve of the steel shot flow detection sensor in the preferred embodiment of the present invention;

[0036] Note in the figure:

[0037] 1. Coil induction component; 2. Signal generation circuit; 3. Voltage conversion circuit; 4. Frequency conversion circuit; 5. Waveform conversion circuit; 6. Voltage-frequency conversion circuit. DETAILED DESCRIPTION

[0038] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered by the claims.

[0039] Example 1:

[0040] This embodiment discloses a steel shot flow detection sensor for a high-pressure water jet sand supply pipe, comprising: a coil induction component 1, a signal generating circuit 2, and a signal conditioning circuit, wherein the signal generating circuit 2 is connected to the induction coil and the signal conditioning circuit respectively;

[0041] The coil induction component 1 is sleeved on the sand supply pipe and is used to sense the flow change of the steel shot in the sand supply pipe and convert the flow change of the steel shot in the sand supply pipe into its own inductive reactance change;

[0042] The signal generating circuit 2 is used to capture the inductive reactance change of the coil induction component 1 and convert the inductive reactance change into a detection signal whose frequency changes with the inductive reactance;

[0043] The signal conditioning circuit is used to convert the detection signal into an output voltage whose magnitude varies with the concentration of the steel shot.

[0044] The present invention discloses a steel shot flow detection sensor for a high-pressure water jet sand supply pipe, comprising: a coil induction component 1, a signal generating circuit 2, and a signal conditioning circuit, wherein the signal generating circuit 2 is connected to the induction coil and the signal conditioning circuit, respectively. The coil induction component 1 is mounted on the sand supply pipe, sensing changes in the steel shot flow rate within the pipe and converting these changes into changes in inductive reactance. The signal generating circuit 2 is configured to capture changes in the inductive reactance of the coil induction component 1 and convert these changes into a detection signal whose frequency varies with the inductive reactance. The signal conditioning circuit is configured to convert the detection signal into an output voltage whose magnitude varies with the steel shot concentration. Compared to existing technologies, the present invention utilizes the coil induction component 1 mounted on the sand supply pipe to sense changes in the steel shot flow rate within the pipe, thereby enabling non-destructive detection of the steel shot flow rate within the pipe.

[0045] Example 2:

[0046] The second embodiment is a preferred embodiment of the first embodiment. The difference between the second embodiment and the first embodiment is that the specific structure of the steel shot flow detection sensor used for the high-pressure water jet sand supply pipe is introduced, which specifically includes the following contents:

[0047] This invention designs a sensor specifically for detecting the metal flow rate of mixed liquid in a hose. Its output voltage ranges from 0 to 10V; higher voltages indicate lower steel shot concentrations in the liquid. This sensor can clearly distinguish between "no steel shot," "normal steel shot flow," and "steel shot blockage" in the sand supply pipe, providing real-time detection for ensuring water jet cleaning quality. This sensor offers numerous advantages, including adaptability to different steel shot types and hose diameters, the need for wall perforation, no disruption to the pipe structure, and no additional joints.

[0048] like Figure 2 As shown, the steel shot flow detection sensor for the high-pressure water jet sand supply pipe disclosed in this embodiment includes: a coil induction component 1, a signal generating circuit 2 and a signal conditioning circuit; wherein the signal conditioning circuit includes a waveform conversion circuit 5, a voltage conversion circuit 3, a frequency conversion circuit 4 and a voltage-frequency conversion circuit 6; the signal generating circuit 2, the waveform conversion circuit 5, the voltage conversion circuit 3, the frequency conversion circuit 4 and the voltage-frequency conversion circuit 6 are connected in sequence; the coil is wound on the outer surface of the coil skeleton and is connected to the signal generating circuit 2.

[0049] The coil sensing assembly 1 consists of a coil bobbin and enameled wire. The coil bobbin is made of PVC tubing and is directly threaded onto the sand supply hose. Enameled wire is then wound around the bobbin to create a single-layer coil of suitable length. The windings are tightly arranged to minimize air gaps. Both ends of the coil are de-varnished and connected to the sensor circuit. The coil winding process is performed solely on the PVC bobbin, eliminating direct contact with the measured pipeline, greatly simplifying the manufacturing process.

[0050] Signal generation circuit 2 consists of a general-purpose operational amplifier U1, a signal capacitor, and a coupling capacitor. When steel shot or other metal abrasives pass through the sand supply tube, the magnetic medium of the coil bobbin changes, causing the coil inductance to change. This change can be captured by this circuit, generating a detection signal whose frequency varies with the metal concentration.

[0051] Specifically, the signal generating circuit 2 includes an operational amplifier U1, a capacitor C1, a capacitor C2, a resistor R3, a resistor R4, and a resistor R5; the non-inverting input terminal of the operational amplifier is connected to the first end of the resistor R3, the second end of the resistor R3 is grounded, and the second end of the resistor R3 is also connected to the first end of the capacitor C1, the second end of the capacitor C1 is connected to the output end of the operational amplifier U1, the inverting input terminal of the operational amplifier U1 is connected to its output end through the resistor R5, the inverting input terminal of the operational amplifier U1 is also connected to the first end of the resistor R4, the second end of the resistor R4 is respectively connected to the first end of the coil and the first end of the capacitor C2, and the second end of the coil is connected to the output end of the operational amplifier; the second end of the capacitor C2 is also connected to the first end of the capacitor C1; in this embodiment, the operational amplifier U1 selects the general-purpose operational amplifier UA741.

[0052] The waveform conversion circuit 5 is composed of a filtering circuit and a waveform conversion circuit. The filtering circuit removes high-frequency interference, and the comparator converts the detection waveform generated by the metal flow sensing circuit into a pulse signal with an amplitude equal to the power supply voltage (VCC). The pulse frequency is equal to the detection frequency.

[0053] Specifically, the waveform conversion circuit 5 includes an operational amplifier U8, a resistor R7, a capacitor C10, and a capacitor C11; the non-inverting input terminal of the operational amplifier U8 is connected to the output terminal of the operational amplifier U1, the inverting input terminal of the operational amplifier U8 and the EMIT / OUT terminal are grounded together, the inverting input terminal of the operational amplifier U8 is also connected to its VCC- terminal through the capacitor C10, and the VCC- terminal of the operational amplifier U8 is also connected to the negative power supply voltage terminal; the output terminal of the operational amplifier U8 is connected to the first terminal of the resistor R7, the second terminal of the resistor R7 and the VCC+ terminal of the operational amplifier U8 are connected to the positive power supply voltage terminal, and the positive power supply voltage terminal is also grounded through the capacitor C11.

[0054] The voltage conversion circuit 3 is used to convert the pulse signal into a TTL-level pulse signal. It consists of two general-purpose operational amplifiers (U5 and U6) and resistors (R1, R2, R6, R14, R15, and R16). The first operational amplifier (U5) performs a reverse proportional amplification operation with an amplification factor of -1 / 3, outputting a negative pulse signal. The second operational amplifier (U6) performs a reverse follower operation with an amplification factor of -1, outputting a TTL positive pulse signal that serves as the input to the frequency conversion circuit.

[0055] Specifically, the voltage conversion circuit 3 includes an operational amplifier U5, an operational amplifier U6, a resistor R1, a resistor R2, a resistor R6, a resistor R14, a resistor R15, and a resistor R16; the inverting input terminal of the operational amplifier U5 is connected to the output terminal of the operational amplifier U8 through the resistor R16, the inverting input terminal of the operational amplifier U5 is also connected to its input terminal through the resistor R6, the non-inverting input terminal of the operational amplifier U5 is grounded through the resistor R2, the output terminal of the operational amplifier U5 is connected to the inverting input terminal of the operational amplifier U6 through the resistor R14, the inverting input terminal of the operational amplifier U6 is also connected to its output terminal through the resistor R15, the non-inverting input terminal of the operational amplifier U6 is grounded through the resistor R1, and the output terminal of the operational amplifier U6 is also connected to the input terminal of the frequency conversion circuit 4;

[0056] In this embodiment, the operational amplifiers U5 and U6 are general-purpose operational amplifiers UA741.

[0057] Among them, the frequency conversion circuit 4 uses an integrated gate circuit to down-convert the received signal. The output of this part of the circuit is a TTL pulse signal of about 5V, and the output frequency is half of the output frequency of part 4 to avoid sensor saturation;

[0058] Specifically, the frequency conversion circuit 4 is an integrated D flip-flop. The PRSET and CLR terminals of the integrated D flip-flop are shorted to a high level, and the Q# terminal of the integrated D flip-flop is shorted to the D terminal. The CK terminal of the integrated D flip-flop is connected to the output terminal of the operational amplifier U6, and the Q terminal of the integrated D flip-flop is connected to the input terminal of the voltage-to-frequency conversion circuit 6. In this embodiment, the integrated D flip-flop is an XD74LS74.

[0059] The main components of voltage-to-frequency conversion circuit 6 are the integrated voltage-to-frequency chip U7, resistors, potentiometers, and capacitors. This unit outputs a voltage, Vout, equal to fin × 2.09 × RL / RS × (RTCT). By properly selecting the values ​​of the resistors and capacitors, the output voltage can be linearly aligned with the input frequency signal. This voltage is also the sensor's final output signal.

[0060] Among them, the THR end of the integrated voltage-frequency chip U7 is connected to the Q end of the integrated D trigger through the capacitor C12, and the THR end of the integrated voltage-frequency chip U7 is also connected to the positive power supply voltage end through the resistor R8. The R / C end of the integrated voltage-frequency chip U7 is connected to the first end of the capacitor CT, and the second end of the capacitor CT is grounded together with the GND end and the FREQ OUT end of the integrated voltage-frequency chip U7. The R / C end of the integrated voltage-frequency chip U7 is also connected to the positive power supply voltage end through the resistor RT, and the COMP IN end of the integrated voltage-frequency chip U7 is also connected to the positive power supply voltage end through the resistor R9. The COMP IN end of the integrated voltage-frequency chip U7 is also grounded through the resistor R10. The VS end of the integrated voltage-frequency chip U7 is connected to the positive power supply voltage end, and the REF end of the integrated voltage-frequency chip U7 The I end is connected to the first end of the sliding rheostat R13 through the resistor R11, the second end of the sliding rheostat R13 is grounded, and the second end of the sliding rheostat R13 is also connected to the first end of the capacitor C9 and the first end of the resistor RL respectively. The second end of the capacitor C9 and the second end of the resistor RL are both connected to the I OUT end of the integrated voltage-frequency chip U7, and the second end of the resistor RL serves as the output end of the voltage-frequency conversion circuit 6; in this embodiment, the model of the integrated voltage-frequency chip U7 is LM331N.

[0061] The working principle of the steel shot flow detection sensor in the present invention is as follows:

[0062] If there are no steel shots in the sand supply tank, or only clean water passes through the sand supply tank without steel shots, the inductive reactance in the sensor remains unchanged, and the sensor output voltage is about 9.23V, indicating a "no steel shot state"; then the steel shots gradually enter the sand supply pipe, causing the magnetic resistance of the sensor coil to decrease. From fin = 1 / (2×Π× (L×C)-1 / 2), it can be seen that the increase in the inductive reactance of the sensor causes fin to decrease, thereby causing the output voltage to gradually decrease from 9.23V. The output voltage is about 8.02V when the flow is stable, indicating a "normal steel shot flow"; if steel shot blockage occurs, the sensor will output a minimum voltage of about 7.38V. Therefore, the sensor can reflect the size of the steel shot flow through voltage, and can also clearly distinguish the three states of the sand supply pipe: "no steel shot", "normal steel shot flow", and "steel shot blockage", providing reliable protection for the normal operation of the water jet cleaning device. The sensor output characteristic curve is as shown in the figure below. Figure 3 shown.

[0063] Unlike existing electromagnetic induction detection principles, the present invention does not require an excitation coil and does not establish an excitation magnetic field. It only uses a single passive induction coil as the oscillating component of the positive feedback branch of the waveform generation circuit. This reduces the conversion error of the primary magnetic field signal to the electrical signal, improves the overall accuracy, and simplifies the sensing structure.

[0064] Compared with the prior art, the processing circuit of the present invention can use coils with different parameters. It is very flexible when measuring different pipe diameters or when the steel shot flow rate does not reach or exceeds the designed measurement range. It only needs to disassemble and replace the induction coil. The parameters of the new coil can be determined according to the following formula:

[0065] (1)

[0066] (2)

[0067] (3)

[0068] N: the number of turns required to be wound;

[0069] LEN: coil winding length;

[0070] L: inductive reactance of the coil;

[0071] A: external cross-sectional area of ​​the skeleton;

[0072] is the capacitance value of capacitor C1;

[0073] is the capacitance value of capacitor C2.

[0074] Since the output of the sensor linearly follows the frequency of the waveform generating circuit, an expected frequency range can be pre-set according to formula (3) to obtain the expected coil inductance, and then combined with (1) and (2) to obtain the number of coil turns required;

[0075] Alternatively, without replacing the coil, it is also possible to change the waveform frequency by disassembling and replacing C1 and C2 of the circuit and changing the size of the capacitor according to formula (3), ensuring that the output voltage can still be within 0~10V when measuring extremely small metal flow or ultra-large flow pipelines.

[0076] Specifically, the working process of the steel shot flow detection sensor in the present invention is as follows:

[0077] Step 1: The coil skeleton is made of PVC tube, and 0.8mm enameled wire is used to wind it on the skeleton to make a single-layer coil with a length of 2.8cm. The windings are arranged closely to reduce the air gap. The two ends of the coil are de-varnished and connected Figure 2Positions C and D in the middle. The PVC frame of the coil can be put on any position of the sand supply pipe to start measurement. Taking a sensor as an example, the initial inductance value of the coil is 28.73uH and the quality factor Q of the coil is 13.42.

[0078] Step 2: At this time, a detection signal is generated at point C of the circuit. When no steel shot passes through the sand supply pipe, the detection signal frequency is 18.46KHz. When steel shot or other metal abrasives pass through the sand supply pipe, the magnetic medium of the coil skeleton changes. Generally, the magnetic resistance of metal is smaller than that of water or air, so the inductive reactance of the coil will increase and the signal frequency will gradually decrease. When the steel shot flow rate stabilizes, the signal frequency at point C of the circuit is 16.0KHz.

[0079] Step 3: The filter circuit removes high-frequency interference, preventing clutter from being misinterpreted as a valid signal. At this point, the operational amplifier comparator implements a comparison output with a low level. This device converts the detection waveform generated by the metal signal detection circuit into a positive pulse signal with an amplitude equal to the power supply voltage (VCC). This signal is output at point P in the circuit diagram. The pulse signal frequency is equal to the detection frequency generated by the metal signal detection circuit, which is 18.46 kHz when there is no steel shot in the sand supply pipe and 16.0 kHz when the steel shot flow rate is normal.

[0080] Step 4: The operational amplifier UA741 converts the pulse signal generated by the waveform shaping and conversion circuit into a TTL-level pulse signal for subsequent TTL circuit processing. The first UA741 implements a reverse proportional amplification operation, with a negative feedback resistor of 10 kΩ and a reverse input resistor of 30 kΩ. The amplification factor is -1 / 3, resulting in a negative-going pulse signal output. The second UA741 implements a reverse follower operation, with a feedback resistor equal to the input resistor and an amplification factor of -1. It outputs a TTL positive pulse signal with a frequency equal to the pulse signal output by the waveform shaping and conversion circuit. In the circuit diagram, the output is P_5V, which serves as the input of the frequency conversion circuit.

[0081] Step 5: By integrating the XD74LS74 D-type flip-flop, shorting the "PRSET" and "CLR" pins to a high level, and shorting the "Q#" and "D" pins, the "CLK" pin receives the P_5V output in the circuit diagram. This outputs a TTL pulse signal on the "Q" pin. At this point, the pulse frequency is reduced to half the frequency of "CLK," preventing sensor output saturation. When the sand supply pipe is empty and the shot flow rate is normal, the pulse frequencies are 9.23 kHz and 8.0 kHz, respectively.

[0082] Step 6: The main components of this part are the integrated voltage-frequency chip LM331 and resistors, potentiometers, and capacitors. The output voltage V out = f in ×2.09×R L / (R11 + R 13 )×(R T C T ), where R L Take 100 kΩ, R T Take 6.81 kilo-ohms, C t Take 0.01uF, then V out = f in ×14.23 / (R 11 + R 13 ), if R 13 Adjust to 2.23 kilo-ohms, then V out = f in ×10 -3 (V), thus achieving the output voltage following the input frequency signal. This voltage is also the final output signal of the sensor. When only clean water and steel shot flow through the sand supply pipe are normal, the voltages are 9.23V and 8.0V respectively. When the steel shot is blocked, the output is 7.38V. Therefore, the higher the steel shot flow, the lower the output voltage, and the value range is [7.38V, 9.23V]. At this point, the size of the steel shot flow in the sand supply pipe can be accurately judged by the voltage.

[0083] In summary, the steel shot flow detection sensor for a high-pressure water jet sand supply pipe according to the present invention comprises: a coil sensing assembly 1, a signal generating circuit 2, and a signal conditioning circuit, the signal generating circuit 2 being connected to the induction coil and the signal conditioning circuit, respectively. The coil sensing assembly 1 is mounted on the sand supply pipe and is used to sense changes in the steel shot flow rate within the pipe and convert these changes into changes in inductive reactance. The signal generating circuit 2 is used to capture changes in the inductive reactance of the coil sensing assembly 1 and convert these changes into a detection signal whose frequency varies with the inductive reactance. The signal conditioning circuit is used to convert this detection signal into an output voltage whose magnitude varies with the steel shot concentration. Compared to existing technologies, the present invention utilizes the coil sensing assembly 1 mounted on the sand supply pipe to sense changes in the steel shot flow rate within the pipe, enabling nondestructive detection of the steel shot flow rate within the pipe. Furthermore, the present invention includes a frequency conversion circuit 4 to prevent sensor saturation. In addition, the coil skeleton of the present invention has a variable diameter and can adapt to sand supply hoses of different diameters; it is suitable for detecting different types of steel shots and metal abrasives; there are no requirements for the pressure level of the pipeline; there are no requirements for the shape and direction of the pipeline; there is no need to destroy the original pipeline structure; there is no need to add new pipeline joints; it is very convenient to install and can be directly put on the pipe body to be tested without the need for fixed installation.

[0084] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A steel shot flow detection sensor for a high-pressure water jet sand supply pipe, characterized in that: include: A coil induction component, a signal generating circuit and a signal conditioning circuit, wherein the signal generating circuit is connected to the coil induction component and the signal conditioning circuit respectively; The coil induction component is sleeved on the sand supply pipe, and is used to sense the flow change of the steel shot in the sand supply pipe and convert the flow change of the steel shot in the sand supply pipe into its own inductive reactance change; The signal generating circuit is used to capture the inductive reactance change of the coil inductive component and convert the inductive reactance change into a detection signal whose frequency changes with the inductive reactance; The signal conditioning circuit is used to convert the detection signal into an output voltage whose magnitude varies with the concentration of the steel shot; The coil induction assembly includes a coil frame and a coil; the coil frame is a hollow tube for being sleeved on the sand supply pipe; the coil is wound around the outer surface of the coil frame and connected to the signal generating circuit; The signal generating circuit includes: an operational amplifier U1, a capacitor C1, a capacitor C2, a resistor R3, a resistor R4, and a resistor R5; a non-inverting input terminal of the operational amplifier is connected to a first end of the resistor R3, a second end of the resistor R3 is grounded, and the second end of the resistor R3 is also connected to a first end of the capacitor C1, a second end of the capacitor C1 is connected to an output terminal of the operational amplifier U1, an inverting input terminal of the operational amplifier U1 is connected to its output terminal via a resistor R5, and an inverting input terminal of the operational amplifier U1 is also connected to a first end of the resistor R4, a second end of the resistor R4 is respectively connected to a first end of the coil and a first end of the capacitor C2, and a second end of the coil is connected to the output terminal of the operational amplifier U1; a second end of the capacitor C2 is also connected to a first end of the capacitor C1; The parameters of the coil are determined according to the following formula: Among them, N is the number of turns required; LEN is the winding length of the coil; L is the inductance of the coil; A is the outer cross-sectional area of ​​the coil frame, is the capacitance value of capacitor C1, is the capacitance value of capacitor C2.

2. The steel shot flow detection sensor for a high-pressure water jet sand supply pipe according to claim 1, characterized in that: The signal conditioning circuit includes: a waveform conversion circuit, a voltage conversion circuit, a frequency conversion circuit, and a voltage-frequency conversion circuit; the signal generating circuit, the waveform conversion circuit, the voltage conversion circuit, the frequency conversion circuit, and the voltage-frequency conversion circuit are connected in sequence; The waveform conversion circuit is used to perform high-frequency filtering on the detection signal and convert the filtered detection signal into a pulse signal; The voltage conversion circuit is used to convert the pulse signal into a standard level pulse signal; The frequency conversion circuit is used to perform frequency reduction processing on the standard level pulse signal; The voltage-frequency conversion circuit is used to convert the standard level pulse signal after frequency reduction processing into an output voltage whose magnitude varies with the concentration of steel shots.

3. The steel shot flow detection sensor for a high-pressure water jet sand supply pipe according to claim 2, characterized in that: The waveform conversion circuit includes: an operational amplifier U8, a resistor R7, a capacitor C10 and a capacitor C11; the non-inverting input terminal of the operational amplifier U8 is connected to the output terminal of the operational amplifier U1, the inverting input terminal of the operational amplifier U8 and the EMIT / OUT terminal are grounded together, the inverting input terminal of the operational amplifier U8 is also connected to its VCC- terminal through the capacitor C10, and the VCC- terminal of the operational amplifier U8 is also connected to the negative power supply voltage terminal; the output terminal of the operational amplifier U8 is connected to the first terminal of the resistor R7, the second terminal of the resistor R7 and the VCC+ terminal of the operational amplifier U8 are connected to the positive power supply voltage terminal, and the positive power supply voltage terminal is also grounded through the capacitor C11.

4. The steel shot flow detection sensor for a high-pressure water jet sand supply pipe according to claim 3, characterized in that: The voltage conversion circuit includes an operational amplifier U5, an operational amplifier U6, a resistor R1, a resistor R2, a resistor R6, a resistor R14, a resistor R15 and a resistor R16; the inverting input terminal of the operational amplifier U5 is connected to the output terminal of the operational amplifier U8 through the resistor R16, the inverting input terminal of the operational amplifier U5 is also connected to its output terminal through the resistor R6, the non-inverting input terminal of the operational amplifier U5 is grounded through the resistor R2, the output terminal of the operational amplifier U5 is connected to the inverting input terminal of the operational amplifier U6 through the resistor R14, the inverting input terminal of the operational amplifier U6 is also connected to its output terminal through the resistor R15, the non-inverting input terminal of the operational amplifier U6 is grounded through the resistor R1, and the output terminal of the operational amplifier U6 is also connected to the input terminal of the frequency conversion circuit.

5. The steel shot flow detection sensor for a high-pressure water jet sand supply pipe according to claim 4, characterized in that: The frequency conversion circuit is an integrated D flip-flop, the PRSET terminal and CLR terminal of the integrated D flip-flop are short-circuited to a high level, and the Q terminal and D terminal of the integrated D flip-flop are short-circuited; the CK terminal of the integrated D flip-flop is connected to the output terminal of the operational amplifier U6, and the Q terminal of the integrated D flip-flop is connected to the input terminal of the voltage-frequency conversion circuit.

6. The steel shot flow detection sensor for a high-pressure water jet sand supply pipe according to claim 5, characterized in that: The voltage-frequency conversion circuit includes: an integrated voltage-frequency chip U7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor RT, a resistor RL, a sliding rheostat R13, a capacitor C9, a capacitor C12 and a capacitor CT; The THR terminal of the integrated voltage-frequency chip U7 is connected to the Q terminal of the integrated D flip-flop through the capacitor C12, and the THR terminal of the integrated voltage-frequency chip U7 is also connected to the positive power supply voltage terminal through the resistor R8. The R / C terminal of the integrated voltage-frequency chip U7 is connected to the first terminal of the capacitor CT, and the second terminal of the capacitor CT is grounded together with the GND terminal and the FREQ OUT terminal of the integrated voltage-frequency chip U7. The R / C terminal of the integrated voltage-frequency chip U7 is also connected to the positive power supply voltage terminal through the resistor RT, and the COMP IN terminal of the integrated voltage-frequency chip U7 is also connected to the positive power supply voltage terminal through the resistor R9. The COMP IN terminal of the integrated voltage-frequency chip U7 is also grounded through the resistor R10. The VS terminal of the integrated voltage-frequency chip U7 is connected to the positive power supply voltage terminal, and the REF The I terminal is connected to the first end of the sliding rheostat R13 through the resistor R11, the second end of the sliding rheostat R13 is grounded, and the second end of the sliding rheostat R13 is also connected to the first end of the capacitor C9 and the first end of the resistor RL respectively. The second end of the capacitor C9 and the second end of the resistor RL are both connected to the I OUT terminal of the integrated voltage-frequency chip U7, and the second end of the resistor RL serves as the output end of the voltage-frequency conversion circuit.

7. The steel shot flow detection sensor for a high-pressure water jet sand supply pipe according to claim 6, characterized in that: The operational amplifier U1, operational amplifier U5, and operational amplifier U6 are all of model UA741CP, the operational amplifier U8 is of model LM311DR, and the integrated D flip-flop is of model XD74LS74; the integrated voltage-frequency chip U7 is of model LM331N; the coil skeleton is a PVC tube with an adjustable inner hole diameter, and the coil is a single-layer coil wound with enameled wire.

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