JPH0738828Y2 - Vibration meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a vibrometer used for detecting the vibration associated with the operation of a valve such as a steam trap or the vibration of a rotary shaft to confirm the quality of the operation.

2. Description of the Related Art A conventional vibrometer will be described with reference to Japanese Utility Model Publication 1-222107.

A detection needle whose one end is brought into contact with an object to be detected is attached to a casing of the probe, and an ultrasonic microphone using a piezoelectric element is attached to the other end of the detection needle. When the tip of the detection needle is pressed against the object to be detected, mechanical vibration of the object to be detected acts on the piezoelectric element of the ultrasonic microphone through the detection needle.
In response to this, a voltage change occurs in the piezoelectric element. This voltage fluctuation is amplified by an amplifier and the needle of the meter is shaken or the speaker is made to ring. The detection needle is generally made of metal such as stainless steel so that vibration can be easily transmitted. Problem to be Solved by the Invention The above-mentioned problem has a problem in that vibration detection accuracy is poor. That is, since the detection needle made of metal such as stainless steel easily transmits heat, the heat of the object to be detected is transmitted to the ultrasonic microphone through the detection needle, and the vibration level of the microphone changes due to the influence of heat. In particular, a valve used in a steam system, such as a steam trap, has a high temperature, so that the vibration detection accuracy deteriorates.

Therefore, the technical problem of the present invention is to make it difficult for the heat of the detected object to be transmitted to the microphone.

MEANS FOR SOLVING THE PROBLEM The technical means of the present invention taken to solve the above-mentioned technical problem is that a ceramic detection needle, one end of which is brought into contact with an object to be detected, is slid axially in the casing of the probe. Freely attach the ultrasonic microphone using a piezoelectric element to the other end of the detection needle, and bias the ultrasonic microphone with a spring placed in the casing to cause one end of the detection needle to protrude from the casing and resist the spring. By pressing one end of the detection needle against the object to be detected and pushing in the detection needle, a vibrometer characterized by converting mechanical vibration of the object to be detected transmitted through the detection needle into electrical vibration with an ultrasonic microphone. is there.

Action The action of the above technical means is as follows.

When one end of a detection needle made of ceramic is pressed against an object to be detected such as a steam trap, mechanical vibration of the object is transmitted to the detection needle. The vibration of the detection needle acts on the piezoelectric element of the ultrasonic microphone, and the piezoelectric element causes a voltage fluctuation according to the mechanical pressure fluctuation caused by the vibration. Since ceramics can transmit vibrations to the same extent as metals, it is possible to accurately detect mechanical vibrations of an object to be detected. Since the ceramic has a heat insulating property, it is difficult for the heat of the object to be detected to be transmitted to the microphone, and the vibration level of the microphone does not change due to the influence of heat.

Effect of the Invention The present invention has the following unique effects.

Since the detection needle made of ceramic is excellent in heat insulation and it is difficult to transfer the heat of the detected object to the microphone, it is possible to continuously measure a large number of detected objects at high temperature.

Further, since ceramic has excellent surface smoothness and does not rust, the sliding resistance between the detection needle and the casing does not change. Therefore, the pressing force of the detection needle against the object to be detected does not change, and the initial good vibration detection performance can be maintained for a long period of time.

Further, since ceramic has excellent wear resistance, even if the detection needle slides repeatedly in the casing, it does not wear, and this also makes it possible to maintain a good initial vibration detection performance for a long period of time.

EXAMPLE An example showing a specific example of the present invention will be described (see FIG. 1).

The casing is formed of a front end member 2 and a rear end member 3 attached to both ends of a cylinder 1. The tip member 2 is made of a heat insulating material and is formed in a cylindrical shape having a small diameter in the upper part. The detection needle 4 is slidably guided at a portion of the reference numeral 6 provided in the middle of the small diameter portion of the tip member 2.

A cross-shaped notch is provided at the upper end of the tip member 2. A chromel-alumel thermocouple 7 for temperature measurement is arranged outside the tip member 2. The thermocouple 7 is formed by bending an elongated thin plate and is located on the upper side of the projection between the notches of the tip member 2, and the side surface extending downward from both sides of the top surface and located on the side surface of the tip member 2. It consists of departments. A hole is made in the center of the upper surface, and the tip of the detection needle 4 is projected from there. The lower end of the side surface portion is connected to the following printed circuit board 8 mounted inside the cylinder 1. A contraction tube 9 is fitted around the tip member 2 and the thermocouple 7.

The ultrasonic microphone 5 has a cylindrical base 1 in the center of the end plate 10.
1. Plate-shaped piezoelectric elements 12 are bonded and fixed to each other, and both surfaces of the piezoelectric element 12 are connected to terminals 13 and 14 by conducting wires.
The end plate 10 and the terminals 13 and 14 are fitted into a support member 15 made of fluororesin. The outer diameter of the support member 15 is made slightly smaller than the inner diameter of the tip member 2 so that it can move freely in the axial direction.

A cylindrical portion 16 is formed on the upper part of the cylinder 1, and the cylindrical portion 16 and the supporting member 15 are formed.
A spring (17) for urging the support member (15) upward is arranged between them.
An elongated hole 18 is formed in the center of the cylindrical portion 16, and the lead wires from the terminals 13 and 14 of the ultrasonic microphone 5 are connected to the printed circuit board 8 through the hole 18.

The printed circuit board 8 is attached to a holder 19 held by the rear end member 3. The lead wire from the printed circuit board 8 is connected to the connector 20. Reference numerals 21 and 22 are screws for fixing the tip member 2 and the contraction tube 9 to the outer periphery of the cylindrical portion 16 of the cylinder 1.

The vibrometer operates as follows. The portion of the probe cylinder 1 is grasped by hand, the tip of the detection needle 4 is pressed against the object to be detected, and the tip is pushed to the position of the thermocouple 7. The mechanical vibration of the object to be detected passes through the detection needle 4 to cause a pressure fluctuation, and the piezoelectric element 12
Act on. In response to this, a voltage change occurs in the piezoelectric element 12. The electrical signal and the temperature signal from the thermocouple 7 are sent to the printed circuit board 8 for processing, and a display (not shown) displays the judgment of pass / fail.

[Brief description of drawings]

FIG. 1 is a sectional view of a vibrometer probe according to an embodiment of the present invention. 1: Cylinder 2: Tip member 4: Detection needle 5: Ultrasonic microphone 7: Thermocouple 8: Printed circuit board 12: Piezoelectric element 15: Support member 17: Spring

Claims (1)

[Scope of utility model registration request] 1. A ceramic detection needle, one end of which is applied to an object to be detected, is slidably mounted in the casing of a probe in the axial direction, and an ultrasonic microphone using a piezoelectric element is attached to the other end of the probe, the casing. By urging the ultrasonic microphone with a spring placed inside to project one end of the detection needle from the casing and pressing one end of the detection needle against the object against the spring and pushing the detection needle, A vibrometer, which converts mechanical vibrations of an object to be detected transmitted into electric vibrations with an ultrasonic microphone.