Automatic nozzle tester

Abstract

An apparatus and method for measuring a pressure profile of a gas inside a nozzle is provided. An apparatus (101) comprises:-a gas supply (103); -a proportional valve and a flow meter (105), which are connected to the gas supply (103); -a rotatable and movable measurement probe (107), which is connected to the pressure sensor (108); -a nozzle holder (109); -a stepping motor (111) which controls the displacement and rotation of the rotatable and movable measuring probe (107); a digital controller for controlling the stepping motor and the gas flow; data acquisition means; and a computer. The probe is measuring the pressure inside the nozzle, and the apparatus generates a 3D map of the pressure profile of the gas inside the nozzle.

Description

Technical Field

[0001] The present invention relates to a device for measuring the pressure distribution of gas inside a nozzle and a method for measuring the pressure distribution of gas inside a nozzle. Background Art

[0002] A nozzle is a device designed to control the direction or characteristics of a fluid flow, particularly to increase the velocity of the fluid flow as it leaves or enters an enclosed chamber or conduit.

[0003] A nozzle is typically a pipe or tube of varying cross-sectional area that can be used to direct or modify the flow of a fluid (liquid or gas). Nozzles are often used to control the velocity, speed, direction, quality, shape, and / or pressure of the fluid exiting the nozzle. In a nozzle, the velocity of the fluid is increased at the expense of its pressure energy.

[0004] There are different types of nozzles, using gas or liquid or a combination of gas and liquid as fluid.Nozzles can be used as, for example, injectors, sprayers, scrapers in many applications such as, for example, cooling, cleaning, painting or wiping.

[0005] There are several systems for measuring the pressure of the fluid at the nozzle outlet. Such systems are used to optimize the design of the nozzle or to check its efficiency.

[0006] KR20020014572A discloses a method and apparatus for measuring the pressure of an injection nozzle. The apparatus includes a movable stage that measures the pressure of air and liquid ejected from the nozzle and moves vertically and horizontally according to the measurement results.

[0007] When a nozzle is used to wipe a liquid with gas over an elongated element, or when a nozzle is used to spray liquid or gas around an elongated element (e.g., for cooling), the elongated element typically runs inside the nozzle. A uniform pressure distribution around the elongated element is desirable. The shape and cross-sectional area of ​​the elongated element influence the gas pressure distribution and need to be considered. Summary of the Invention

[0008] The present invention is particularly suitable for use with cooling or wiping nozzles placed around elongated elements. Examples of such nozzles include those that blow compressed gas around the elongated element to remove excess liquid. Such nozzles can be used to dry steel wire after exiting a rinse bath containing an aqueous solution, or to cure coatings. Examples of coatings include extruded polymer coatings, paints, or metal coatings obtained by hot-dip processes.

[0009] A first object of the present invention is to provide an apparatus for measuring the pressure distribution of a gas inside a nozzle.

[0010] The device includes:

[0011] One or more gas supplies. The supplied gas may be air, helium, oxygen, carbon dioxide, argon, or nitrogen. Preferably, the gas is compressed air or nitrogen. When more than one gas supply is used, different gases may be supplied to different gas supplies, thereby allowing mixing of the gases within the nozzle.

[0012] -Proportional valves and flow meters are used to control the flow of gas in each supplier. The gas flow rate is 0.01m 3 / h and 15m 3 / h varies.

[0013] A rotatable and movable measurement probe is connected to the pressure sensor. The measurement probe is designed with a specific shape to simulate the elongated element running inside the nozzle. This allows the probe to simulate the elongated element inside the nozzle, providing a more realistic pressure distribution measurement, closer to actual process conditions, than with prior art devices.

[0014] Therefore, the measurement probe can have a circular cross-section to simulate a cylindrical, elongated element to be wiped by the nozzle, such as a wire, rod, bar, pipe, or tube. The measurement probe can have a non-circular cross-section, such as a rectangular, triangular, or elliptical cross-section, to simulate an irregularly shaped elongated element to be wiped by the nozzle, such as an elliptical, flat, or triangular wire, or a shaped wire, such as a U-shaped shaped wire. The measurement probe includes an aperture with a diameter between 0.1 mm and 0.5 mm to collect the gas to be measured. If the probe has an asymmetric, non-circular cross-section, the position of the collection aperture may vary.

[0015] In order to limit the size of the device, the measuring probe preferably has a 1 mm 2 With 200mm 2 For example, a probe with a circular cross-section preferably has an outer diameter between 1.1 mm and 16 mm.

[0016] The nozzle holder is used to hold the nozzle being tested in place.

[0017] A plate or belt or a container containing a liquid such as water may be placed under the nozzles.

[0018] A stepper motor is used in conjunction with a digital controller to position the measurement probe within the nozzle being tested. The digital controller may be a computer. The measurement probe is movable in the direction of a vertical axis and rotatable about the vertical axis.

[0019] The test data includes time, nozzle identification and description, supplied gas type and flow rate, measured gas pressure and nozzle position (angle, height). The test data is collected using any common means for collecting data (such as a data acquisition card) or directly through a cable connected to a network or computer.

[0020] A computer is used to store and analyze the collected data. The computer may be a programmable logic controller (PLC) integrated into the device, or external (eg, a desktop or laptop computer) or remote and connected to the device via a server.

[0021] Using the collected data, the device generates a 3D map of the pressure distribution of the gas inside the nozzle.

[0022] A second object of the present invention is to provide a method for measuring the pressure distribution of gas inside a nozzle using the apparatus described above. The method comprises the following steps:

[0023] Position the nozzle on the nozzle holder;

[0024] Select a probe with an equivalent diameter and shape to the slender element to be simulated;

[0025] Set the starting position by positioning the probe hole at a distance L0 from the bottom of the nozzle;

[0026] 0.01m 3 / h and 15m 3 The compressed gas is supplied to the nozzle at a flow rate of between / h;

[0027] rotating the probe from 0° to 360° in steps selected within the range between 1° and 359° (preferably between 10° and 90°, such as 15° or 30° or 45°);

[0028] moving the probe in a vertical direction with a step size selected in the range between 0.1 mm and 10 mm, for example 0.2 mm or 0.5 mm or 1 mm or 2 mm or 5 mm;

[0029] At each rotation or vertical movement of the probe, the pressure measured by the pressure sensor is recorded;

[0030] Provides data to the data acquisition component: nozzle description, L0, gas flow, time, rotation angle, vertical position, measured gas pressure

[0031] Plot the measured gas pressure as a function of probe position (angle, vertical position) in 3D

[0032] Calculate the total wiping power, absolute factor, and maximum vertical pressure gradient.

[0033] The total wiping power is obtained by selecting the maximum pressure at each angular position of the measuring probe inside the nozzle and calculating the average of these maximum pressures.

[0034] The absolute factor is the ratio between the highest and lowest maximum gas pressures measured at different angular directions. To calculate the absolute factor, the maximum gas pressure measured at each angular position of the measurement probe inside the nozzle is averaged for all vertical positions of the measurement probe inside the nozzle. The highest value of all averages is divided by the lowest value of all averages. This gives the absolute factor. The inverse of the absolute factor gives the ratio of pressure centrality. For example, an absolute factor of 2 indicates a pressure centrality of 50%.

[0035] Calculate the local vertical pressure gradient at each vertical position i of the measurement probe as dP / dz i :

[0036] dP / dz i =(P i+1 -P i ) / (d 高度 )

[0037] where d 高度 is the step length in the vertical direction z between two measurement points i and i+1. The maximum local vertical pressure gradient max(dP / dz i ) is the average value of all angular positions. In a manner similar to the absolute factor, the highest value of all averages divided by the lowest value of all averages is defined as the maximum vertical pressure gradient (dP / dz) max This value gives an indication about the wiping ability of the nozzle. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Detailed view of the device of the present invention

[0039] Figure 2 Schematic diagram of the nozzle and measuring probe

[0040] Figure 3 3D graph of the measured gas pressure as a function of probe position

[0041] Figure 4 is the 2D projection of the measured gas pressure in 2 different nozzles DETAILED DESCRIPTION

[0042] Figure 1 The apparatus of the present invention is shown.

[0043] In this example, the apparatus 101 includes:

[0044] Two gas supplies 103, both connected to a proportional valve and a flow meter 105. The two supplies can be used independently and with different types of gas.

[0045] A rotatable and movable probe 107 is connected to a pressure sensor 108. The probe is moved in the vertical direction and rotated about a vertical axis by a stepper motor 111. A digital controller (not shown) sends information to the stepper motor. The stepper motor can also be controlled by a computer 117.

[0046] The nozzle holder 109 holds the nozzle 119 to be tested securely in place.

[0047] Figure 2 2 is a close-up view of nozzle 219. The holder is not shown. In the illustrative example, compressed air is used and supplied to the nozzle via gas supply 203. A base plate or a container filled with liquid can be placed under the nozzle holder to simulate the distance between the nozzle and, for example, a liquid metal bath. In some examples of this illustrative example, plate 221 is placed under the nozzle to be tested.

[0048] By controlling a stepper motor, the measurement probe 207 is positioned inside the nozzle. In the illustrative example, the measurement probe includes a 0.5 mm diameter hole to collect the compressed air pressure to be measured. The starting "home" position L0 is preferably defined as the position where the small hole in the measurement probe is aligned with the bottom of the nozzle. The reference position can also be the nozzle scraper or any other preferred position. The starting position L0 can be stored in the device to allow for automatic positioning.

[0049] Before starting the measurement, the nozzle description needs to be entered into the device. This can be done using the computer 117 connected to the device. For the two gas supplies 103, the gas flow rate can be set independently at 0.01m 3 / h and 15m 3 / h.

[0050] The stepper motor can be configured according to the desired resolution of the pressure scan. The resolution of the pressure scan is determined by the sampling rate and the rotational and vertical displacement step sizes of the measurement probe.

[0051] The rotation of the measuring probe can be configured in steps between 1° and 359°, preferably between 10° and 90°, for example 15° or 30° or 45°.The motor speed can be adjusted to a percentage of its maximum speed, for example 50%.

[0052] The vertical displacement of the measuring probe may be configured in steps between 0.1 mm and 10 mm, for example 0.2 mm or 1 mm.

[0053] The sampling rate can be 1s-1 with 1000s -1 This is the number of measurements per second at a given position. The duration of the measurement at each position can also be selected between 1s and 100s.

[0054] For example, a nozzle has been selected and placed on a nozzle holder with a 0.5 mm thick plate at a distance of 1 mm from the bottom of the nozzle.

[0055] Use a gas supply with a flow rate of 4m 3 / h. The pressure is measured by a pressure sensor connected to a probe with a sampling rate of 100s -1 The probe was moved in the vertical direction with a step size of 0.2 mm and rotated around the vertical direction with a step size of 10°.

[0056] The pressure measured at each location is recorded and stored in a connected computer, and a 3D graph is created using the collected data.

[0057] Figure 3 is an example of a 3D plot of the pressure distribution inside the tested nozzle. In this particular example, it can be seen that the pressure distribution is asymmetric due to wear inside the nozzle.

[0058] Figure 4 Shown are projections of pressure measurements in the XY and XZ planes for 2 different nozzles, with and without a plate at the bottom.

[0059] From left to right, Figure 4 Shown in the following each inside 4m 3 Pressure measurement results at a flow rate of / h:

[0060] - Old nozzles without a plate at the bottom;

[0061] -Same old nozzle with a 0.5mm plate 1mm from the bottom;

[0062] - New nozzles without a plate at the bottom;

[0063] -Same new nozzle with 0.5mm plate 1mm from the bottom.

[0064] A convenient way to compare the efficiency of different nozzles is to use the absolute factor. The absolute factor is the ratio between the highest maximum gas pressure and the lowest maximum gas pressure measured at different angular directions.

[0065] An absolute factor value of 1 means that the pressure is evenly distributed. Therefore, a "good" nozzle should have the lowest possible absolute factor.

[0066] exist Figure 4 In the example of , the old nozzle has an absolute factor of 36.7 without the plate and an absolute factor of 4.8 with the plate, while the new nozzle has an absolute factor of 1.9 without the plate and an absolute factor of 1.4 with the plate.

[0067] Another way to compare different nozzles is the maximum vertical pressure gradient (dP / dz) max The maximum vertical pressure gradient is the ratio between the highest maximum gas pressure and the lowest maximum gas pressure measured at different altitudes.

[0068] exist Figure 4 In the example of FIG, the maximum vertical pressure gradients are calculated to be (from left to right) 3.68, 5.48, 17.32, and 5.41, respectively. A higher maximum vertical pressure gradient indicates better local wiping ability.

[0069] Reference Signs List

[0070] 101 Installation

[0071] 103, 203 gas supply

[0072] 105 Proportional valve and flow meter

[0073] 107, 207 Rotatable and movable probe

[0074] 108 pressure sensor

[0075] 109 Nozzle Holder

[0076] 111 Stepper Motor

[0077] 117 Computer

[0078] 119, 219 nozzles

[0079] 221 Plate or strip at the bottom of the nozzle

Claims

1. A device (101) for measuring the pressure distribution of gas inside a nozzle, the device comprising: -Gas supply (103) - a proportional valve and flow meter (105) connected to the gas supply (103) - a rotatable and movable measuring probe (107) connected to a pressure sensor (108) -Nozzle holder (109) - a stepper motor (111) which controls the displacement and rotation of the rotatable and movable measuring probe (107) - A digital controller for controlling the stepper motor and gas flow -Data acquisition components -computer It is characterized by The rotatable and movable measurement probe is arranged to be positioned inside the nozzle to measure the pressure at different locations inside the nozzle, such that the apparatus can generate a 3D map of the pressure distribution of the gas inside the nozzle.

2. The apparatus of claim 1, further comprising one or more additional gas suppliers. 3 . The apparatus of claim 2 , wherein the gas supplied to the first gas supply is different from the gas supplied to the one or more additional gas supplies.

4. The device according to any of the preceding claims, wherein the measuring probe rotates from 0° to 360° about a vertical axis in steps of between 1° and 359° and moves along the vertical axis in steps of between 0.1 mm and 10 mm.

5. The device according to any one of the preceding claims, wherein the gas flow rate is 0.01m 3 / h and 15m 3 / h varies.

6. The device of any preceding claim, further comprising a plate or belt at the bottom of the nozzle.

7. A device according to any one of the preceding claims, wherein the measuring probe has a circular cross-section to simulate a cylindrical elongated element to be wiped inside the nozzle.

8. The device according to any one of claims 1 to 6, wherein the measuring probe has a non-circular cross-section, such as a rectangular cross-section or a triangular cross-section or an elliptical cross-section, to simulate a profiled elongated element to be wiped inside the nozzle.

9. The device according to claim 7 or 8, wherein the probe has a diameter of 1 mm. 2 With 200mm 2 The cross-sectional area between.

10. The device according to any one of claims 1 to 6, wherein the supplied gas is air, or nitrogen, or oxygen, or helium, or argon, or carbon dioxide.

11. A method for measuring the pressure distribution of gas inside a nozzle using the device according to claim 1 or 2, the method comprising the following steps: - positioning the nozzle on the nozzle holder; - selecting a probe similar to said elongated element to be simulated, with an equivalent diameter and shape; - Setting the starting position by positioning the probe hole at a distance L0 from the bottom of the nozzle; -0m 3 / h and 15m 3 Supplying compressed gas to the nozzle at a flow rate of between 1 / 2 and 2 / 3 hours; - rotating the probe from 0° to 360° in steps selected within the range between 1° and 359°; - moving the probe in the vertical direction with a step size selected in the range between 0.1 mm and 10 mm; - at each rotation or movement of the vertical probe, recording the pressure measured by the pressure sensor; - Provides data to the data acquisition card: nozzle description, L0, gas flow, time, rotation angle, vertical position, measured gas pressure at each probe position; -Send data to the computer.

12. The method according to claim 11, further comprising the steps of: - Plotting the measured gas pressure as a function of the probe position in 3D.

13. The method according to claim 11 or 12, further comprising the steps of: The total wiping power is calculated by selecting the maximum pressure at each angular position of the measuring probe inside the nozzle and calculating the average of these maximum pressures.

14. The method according to claim 11 or 12, further comprising the steps of: - Calculation of an absolute factor as defined by the ratio between the highest maximum gas pressure and the lowest maximum gas pressure measured in different angular directions.

15. The method according to claim 11 or 12, further comprising the steps of: - Calculation of the maximum vertical pressure gradient as defined by the ratio between the highest and lowest maximum gas pressures measured at different altitudes.

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