JPH02204689A - Discharge air quantity measuring method and device for air compressor - Google Patents

Abstract

PURPOSE:To simplify a measuring job by setting up a discharge air quantity measuring device in an atmosphere inlet port of an air compressor, measuring air speed at this inlet port, and calculating an intake air quantity from this measured value for finding a discharge air quantity. CONSTITUTION:A sensing probe B consisting of a bridge circuit part A assembled with resistors 1, 2, a temperature sensor 3 and an sir speed sensor 4 in bridge is set up in an inlet port 5 of an air compressor in applying a flat surface 8a to an inlet edge so as to make a long hole aperture 11 accord with the center. When the atmosphere is inhaled out of the inlet port 5, voltage balance comes down between the air speed sensor 4, where temperature goes down and resistor value varied as heat is absorbed by an air flow, and the temperature sensor 3 kept in the specified temperature, and this voltage difference gets into an air speed/air quantity converting part 7 via a heating control part 6, converted into a discharge air quantity, and then it is displayed on an indicator 9 via a selector range 10. Thus, measurement of the discharge air quantity can be done simply.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for measuring the amount of air discharged from an air compressor, which can measure the amount of air discharged from the wind speed at the air suction port of the air compressor. Regarding.

(Prior art and its problems) In the most basic case, the discharge air volume of an air compressor that is connected to factory power equipment or instrumentation equipment, etc. is checked by five senses once the connection is completed. Based on qualitative observations, the construction was deemed complete. In addition, a simple method for measuring the amount of discharged air is the air tank filling method (operating the air compressor to increase the pressure in the air tank from atmospheric pressure to the specified pressure, measuring the time required for this and the temperature of each part, and then compressing the air. A method of calculating the amount of air discharged by the machine was used, but the accuracy varied and was a problem in practice.

Therefore, if more precise operation is required, ■ Install an air tank at the discharge port of the air compressor, maintain the tank internal pressure at the specified pressure, and operate continuously, and when the operating condition becomes stable, wet gas flow The discharge flow rate was measured using a meter or float-type area flow meter, and the wind tube measurement method was used. However, according to JIS regulations, the amount of discharged air must be expressed by converting it into the volume of the suction state under atmospheric pressure, and if it can be measured directly at the suction port, it will be much more effective than the above-mentioned method. It's advantageous.

Now, to briefly describe the history of air compressors, the drive unit of early air compressors was a reciprocating type, so
There were pulsations in the compressed air discharge, so that measurements at the atmospheric inlet were not possible. Therefore, in order to precisely measure the amount of air discharged from factory equipment, first remove the factory piping from the air compressor's discharge port, install a large-capacity air tank in its place to alleviate the pulsation on the discharge side, and then attach the air volume to the air tank. The amount of air discharged was measured by installing various instruments such as meters and installing wind pipes. In this case, correct the temperature and pressure to correct the inhalation condition. It is necessary to convert the air of E1 (under atmospheric pressure) into 1 cm of air, which requires a skilled measuring technique, and it is not easy to measure the amount of discharged air. In addition, measuring the amount of discharged air not only requires a large measurement space as mentioned above, but also involves problems such as the labor involved in disassembling and reassembling factory piping, and drain treatment associated with pressurized air. In this respect, measurement on the discharge side could not be easily performed.

However, recently, screw type air compressors have become mainstream, and the historical background has finally been established that pulsation is reduced and there is no problem with accuracy even if measurements are taken at the inlet.

(Purpose) The present invention has been made in view of the drawbacks of the conventional examples, and its purpose is to provide an air system that can accurately and easily measure the amount of discharged air by simply setting a device for measuring the amount of discharged air in the suction port. The present invention provides a method for measuring the amount of air discharged from a compressor and a device therefor.

(Means for Solving the Problems) In the method of the present invention in 11, ■ a discharge air amount measuring device tf (X) is installed at the air intake port (5) of the air compressor, and The wind speed is measured, the amount of intake air is calculated using a conversion formula for calculating the amount of discharged air from the wind speed, and the calculated value is displayed as the amount of discharged air.

In 1λ1, two resistors (1) (2), a temperature sensor (3) and a wind speed sensor (4) placed at the air compressor inlet (5) are adopted. are assembled into a bridge to form a bridge circuit section (^), ■ a heating control section (6) that detects the voltage balance of the bridge circuit section (^) during air intake, and ■ a heating control section (6). A wind speed/air amount converter ()) that converts the detected wind speed of intake air into an air amount constitutes an air compressor discharge air amount measuring device.

In the 111, the wind speed sensor (4) and temperature sensor (3) are housed in a semicylindrical case (8), and the tip of the spoon is equipped with a wind speed sensor (4) and a temperature sensor (4). A technical measure is adopted in which the time constants of the temperature sensors (3) are made the same.

(Function) ■First, install the sensing probe (B) at the air compressor's intake port (5).

■ At this time, select the same marks (12) written on both sides of the slotted window (11) so that the slotted window (11) is aligned with the center of the intake slot (5), and At the same time, place the flat surface (8a) of the sensing probe (B) on the rim of the suction port (5).

■Atmospheric air is inhaled through the inlet (5), but some of the inhaled air flows through the long hole window (11) of the sensing probe (B).
flows through the temperature sensor (3) as well as the wind speed sensor (4).
) removes heat from the body.

■Then, a voltage imbalance occurs between the temperature sensor (3), which is maintained at a predetermined temperature, and the wind speed sensor (4), whose temperature decreases due to heat being taken away and whose resistance changes. The difference is input to the heating control section (6).

(2) The output of the heating control section (6) is then input to the wind speed/air amount converting section (7), and is converted into a discharge air amount using a conversion formula described later.

■The discharge air volume converted by the wind speed/air volume converter (7) is transferred to the discharge air volume indicator (
9), and the amount of discharged air is displayed.

(Example) Hereinafter, the present invention will be explained according to illustrated embodiments.

Examples of the discharge air amount measuring device (X) used in the present invention include a hot wire type that uses an electronic circuit, a vane type that measures wind speed by rotating an impeller, and other types. There are several types, but here we will use a hot wire type as an example. This circuit is roughly divided into: ■Bridge circuit section (^), ■Heating control section (6), ■Wind speed/air amount change fi M (7), ■Switching range (10), ■Discharge air amount indicator (9) It is classified as The bridge PF circuit section (^) consists of two resistors (1) (2) and a temperature sensor (
3) and the wind speed sensor (4) are housed in a sensor case (8) with a semicylindrical cross section to form the sensing probe (B).There is a net in the center of the sensor case (8). An oblong window (11) with a
) and the wind speed sensor (4) are looking into it.
Marks (12) are engraved symmetrically on both sides of the oblong window (11) on the dome-side surface of the sensor case (8), and align the sensing probe (B) with the inlet port (5) to match the marks (12). ). The two resistors (1) and (2) are selected to have approximately the same resistance value, and the temperature sensor (3) and wind speed sensor (
4) is one in which the time constants are almost the same, and the rise reaction rate is thereby significantly improved.

This is shown in Table 1, where two resistors (
1) (2) and temperature sensor (3) and wind speed sensor (4)
The connection point of the heating control section (6) is connected to the input of the heating control section (6), so that a minute voltage imbalance in the bridge circuit section (^) can be immediately detected. Heating control section (6)
The output of is connected to the input of the wind speed/air amount converter (A), which converts the amount of air on the intake side into the amount of discharged air using the following conversion formula.

The conversion formula is shown below.

Qv-60・Vs・π・D2÷4・・・Conversion formula %
(Formula %) The amount of air calculated using the above conversion formula is displayed on the needle hole or digital indicator (9) that displays the amount of discharged air.

The indicator (9) is provided with a switching range (10) so that the range (10) can be switched according to the amount of air.

Next, a case will be described in which the amount of air is measured using the discharge air amount measuring device of the present invention. First, the suction filter of the air compressor is removed to open the suction port (5), and the sensing probe (B) is installed in the suction port (5). At this time, select the same marks (12) written on both sides of the long hole window (11) so that the long hole window (11) coincides with the center of the suction port (5), and Add it to the edges. At this time, the semicylindrical sensing probe (B) is placed so that the flat surface (8a) is in contact with the rim of the mouth. This ensures that the elongated window (11) is located precisely in the center of the suction port (5). Atmospheric air is sucked into the suction port (5), but a portion of the sucked air passes through the long hole window (11) of the sensing probe (B) and comes into contact with the temperature sensor (3) and the wind speed sensor (4). This will take heat away from these. The temperature sensor (3) is maintained at a predetermined temperature, while the temperature of the wind speed sensor (4) changes depending on the wind speed, so that the resistance value changes. As a result, the voltage imbalance in the bridge circuit section (^) increases in proportion to the wind speed, and this voltage difference is input to the heating control section (6).The output of the heating control section (6) is then /Air amount converter (7)
is input and converted into air amount using the above conversion formula. wind speed/
The amount of air converted by the air volume converter (7) is output to the discharge air amount indicator (9) via the switching range (10), and the air amount is displayed in the needle hole. Although it is a display meter, it is of course not limited to this, and may display digitally, or may be connected to a recorder to record the momentary air film on recording paper. It is sufficient to measure the amount of air at the air compressor inlet (5) once as long as the air entering the inlet (5) is completely turbid, but to ensure accuracy
It is desirable to measure by rotating the open position 4 to 8 times so that they intersect. This cancels out the inflow vector of the intake air and improves measurement accuracy.

Incidentally, the accuracy when measuring four times at different orthogonal positions is within a range of about ±5% compared to conventional measurement results, which is sufficient for practical use.

In addition, since the aperture of the inlet (5) appears as a variable in the first equation, the aperture should be changed when the sensor case (8) is aligned with the inlet (5). At (10a), it is input to the wind speed/air amount converter ()).

Moreover, the wind speed sensor (4) and the temperature sensor (3) in the present invention
) It was found during the tests that the closer the time constants of the temperature sensor, the better the start-up response.The relationship is shown in the table below. (Results of 95% rise response characteristics) Table 1 Sample...A response test was conducted with a sensor resistance of 20Ω to 200Ω.

(Effects) As shown in LL''L, the method of the present invention installs a discharge air amount measuring device at the atmospheric suction port of an air compressor, measures the wind speed at the suction port, and measures the air flow rate based on the above conversion formula. Since the amount of discharged air is displayed by calculating the amount of air discharged, it is not necessary to remove the factory piping and connect a large capacity air tank and various instruments to store the actually discharged air up to a predetermined pressure, and to use expensive instruments. It is possible to directly measure the air inhaled from the suction port by removing the suction filter and exposing the suction port, without requiring complicated operations such as measuring the amount of discharged air using a The first advantage is that the measurement process is simple, the second advantage is that the measurement process does not take up much space, and the third advantage is that it eliminates the drain that comes with measurement on the discharge side. Fourthly, since the measurement is performed on the suction side, there is no need for pressure correction or temperature correction, and the measurement work is very simple and does not require a skilled technician. There is.

In addition, a bridge circuit section is constructed by assembling two resistors, a temperature sensor and a wind speed sensor arranged at the intake port of the air compressor into a bridge, and the voltage balance of the bridge circuit section during ventilation is detected. A heating control section and a wind speed/air amount conversion section that converts the wind speed of the intake air detected by the heating control section into a discharge air amount using the above calculation formula constitute a discharge air amount measuring device of an air compressor. Therefore, it is possible to easily measure the amount of discharged air by simply placing the wind speed sensor and temperature sensor of the bridge circuit in the intake air. By placing the flat surface of the sensor case against the intake port, the sensor can be installed accurately at the intake port, and measurement errors can be reduced in this respect. Since the time constants of the wind speed sensor and temperature sensor are the same in 1 and 1, the start-up response is improved and is less susceptible to the effects of thermal turbulence inside the air compressor, making it possible to measure almost instantly at room temperature. It has the advantage of being

[Brief explanation of the drawing]

Figure 1: Block circuit diagram of one embodiment of the present invention Figure 2: Front view of the sensor case used in the present invention Figure 3:
...Side view of Fig. 2 Fig. 4...Front view of the inside of the sensor case used in the present invention Fig. 5...Front view showing the measurement state according to the present invention Fig. 6...Fig. 5 Side view (^)...Bridge circuit section (B)...Sensing probe (X)...Discharge air amount measuring device (1) (2)...Resistance (3)...Temperature sensor (4) )...Wind speed senna (5)...Intake port (6
)...Heating control section (7)...Wind speed/air amount converter (8)...Sensor case (8a)...Flat surface (9)...Discharge air amount indicator (10) ...Switchable range (10g)...Digital switch (11)
...Long hole window (12)...Mark

Claims (4)

[Claims] (1) An air compressor characterized in that a discharge air volume measurement device is installed at the air suction port of an air compressor and the wind speed at the suction port is measured, thereby calculating the intake air volume and determining the discharge air volume. How to measure the amount of air discharged from the machine. (2) Construct a bridge circuit section for wind speed sensing by assembling two resistors, a temperature sensor and a wind speed sensor placed at the air compressor intake port into a bridge, and detect the voltage balance of the bridge circuit section. A discharge air amount measuring device for an air compressor, comprising a heating control section and a wind speed/air amount converting section that converts the wind speed detected by the heating control section into a discharge air amount. (3) The device for measuring the amount of air discharged from an air compressor according to claim (2), wherein the wind speed sensor and the temperature sensor are housed in a semicylindrical case with a flat contact surface. (4) The air compressor discharge air amount measuring device according to claim (2), wherein the time constants of the wind speed sensor and the temperature sensor are made the same.