JPS6246815B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for measuring the amount of gas leaking from an object to be measured, such as a pressure tank, conduit, or connecting member that stores or conveys a gas such as compressed air.

A method for measuring the amount of gas leaking from an object to be measured, such as a pressure tank, in which it is difficult or impossible to measure changes in its own weight and the weight of the gas stored therein. One method that has been known is the leaving method. In this method, a gas such as compressed air that is equal to the pressure of the gas when the object is in use is sealed inside the object to be measured, and the pressure of the gas inside the object decreases due to leakage. The rate of pressure drop at that time is determined, and the amount of gas leaked per unit time is calculated as the leakage weight when the gas pressure is P ₀ according to the following formula.

(dG/dt) _P0 = V/RT・dP ₀ /dt ...(A) Here, V = Volume of the object to be measured R = Gas constant T = Absolute temperature of gas dP ₀ /dt = Pressure at P ₀ However, in general, the volume V of an object to be measured such as a pressure tank is often unknown, and it is difficult to measure or calculate the volume. It is not possible to determine the amount of gas leaking from within the object to be measured using the leaving method.

The present invention provides a method and an apparatus that can accurately measure the amount of gas leaking from the inside of an object to be measured, even when the volume of the object to be measured is unknown. is intended to provide.

According to the present invention, the present invention provides _a method for measuring the amount of gas leaking from an object to be measured whose volume is _Vx . a second container, a first conduit having a volume of V ₃ and communicatively connecting the object to be measured and the first container to form a first _volume system; a second conduit that communicates and connects the object to be measured and the second container to constitute a second volume system; and pressurization for supplying pressurized gas to the first and second volume systems. a gas source, a first valve device for blocking communication between the first volumetric system and the pressurized gas source, and a second valve device for blocking communication between the second volumetric system and the pressurized gas source. Using a gas leakage measuring device having a valve device and a measuring device that continuously measures the pressure of the gas in the first and second volumetric systems, the first volumetric system is formed by communicating with the first container, the pressurized gas from the pressurized gas source is introduced into the first volumetric system, and the first volumetric system is When the pressure of the gas in the first volume system reaches a predetermined pressure _P1 , the first valve device is closed, the pressure change of the gas in the first volume system is measured by the measuring device, and the first valve device is closed. Determine the pressure drop rate dP ₀ /dt at the time when the pressure of the gas in the volumetric system reaches a predetermined pressure P ₀ , and connect the object to be measured and the second container through the second conduit. are connected in communication to form the second volumetric system, pressurized gas from the pressurized gas source is introduced into the second volumetric system, and the pressure of the gas in the second volumetric system is increased. When a predetermined pressure _P2 is reached, the second valve device is closed, the pressure change of the gas in the second volume system is measured by the measurement device, and the gas in the second volume system is The pressure drop rate dP ₀ '/dt at the point when the pressure reaches the predetermined pressure P ₀ is determined, and from this, the following equations (1), (2), and (3) are combined to form the above equation. A method of calculating the amount of gas leaked per unit time when the pressure of the gas inside the object to be measured is P ₀ using the following formula (4), where the leakage weight (dG/dt) _P0 is calculated as (dG/dt). ) _P0 = (V ₁ +V ₃ +Vx)/RT・d
P ₀ /dt...(1) (dG/dt) _P0 = (V ₂ +V ₄ +Vx)/RT・d
P ₀ '/dt...(2) V ₄ =V ₃ +k (k: constant)...(3) Here, R=gas constant T=absolute temperature of gas and an apparatus for measuring the amount of gas leaking from inside an object to be measured, comprising first and second containers having mutually different known volumes, and the object to be measured. A first conduit that connects the object to be measured and the first container to form a first volume system; and a first conduit that connects the object to be measured and the second container to form a second volume system. A second conduit constituting the system, a pressurized gas source supplying pressurized gas to the first and second volumetric systems, and communication between the first volumetric system and the pressurized gas source. a first valve device for blocking communication between the second volumetric system and the pressurized gas source; and a second valve device for continuously measuring the pressure of the gas in the object to be measured. This is accomplished by a device having a measuring device.

According to the method for measuring the amount of gas leakage according to the present invention, two volume systems including the object to be measured whose amount of gas leakage is to be measured and having different volumes are configured, and the leaving method is applied to each of them, and the above-mentioned method is applied to each volume system. The relationship in Equation (A) is determined, and the solution is the gas leakage amount per unit time, which is a simultaneous equation. Therefore, even if the volume of the object to be measured is unknown, The amount of gas leaking from inside the object can be easily and accurately measured. Furthermore, according to the method according to the present invention, the volume of the object to be measured can also be easily and accurately determined as another solution to the above-mentioned simultaneous equations.

Further, according to the gas leakage measuring device according to the present invention, the method for measuring the amount of gas leakage as described above can be carried out efficiently.

In the method and apparatus of the present invention, it is preferable that k=0, that is, the volume V ₃ of the first conduit and the volume V ₄ of the second conduit are equal, and in this case, the simultaneous equations are When unraveling, there is no need to correct the difference in volume between the first conduit and the second conduit. Further, in the method and apparatus according to the present invention,
It is preferable to measure the amount of leakage by sharing one conduit as the first conduit and the second conduit and connecting the first and second containers to that conduit in sequence; Even if the volume of the conduit is unknown, the amount of gas leaking from within the object to be measured can be measured.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be explained in detail below by way of example embodiments with reference to the accompanying figures.

FIG. 1 is a schematic diagram showing one embodiment of a gas leakage measuring device according to the present invention. In the figure,
The gas leakage measuring device according to the present invention includes first and second containers 1 and 2 having known volumes V ₁ and V ₂ that are different from each other, and an object 3 whose gas leakage is to be measured. It includes a first conduit system 4 that communicates and connects the object to be measured 3 and the first container 1, and a second conduit system 5 that communicates and connects the object to be measured 3 and the second container 2. There is. The first conduit system 4 has a conduit 6 connected to the object to be measured 3 at one end.
and a conduit 8 which is connected to the first container 1 at one end, connected to the other end of the conduit 6 at the other end, and has an on-off valve 7 in the middle. The second conduit system 5 is composed of a conduit 6 and a conduit 10 that is connected to the second container 2 at one end, connected to the other end of the conduit 6 at the other end, and has an on-off valve 9 in the middle. There is.

The conduit 6 is connected to a compressed air supply source 12 by a conduit 11.
are connected to each other, and an on-off valve 13 is provided in the middle of the conduit 11. In addition, conduit 1 is connected to conduit 6.
A pressure measuring device 15 is connected by 4, and the pressure measuring device 15 can continuously measure the pressure of the gas in the conduit 6, and the measured data can be continuously recorded by a recording device 16. It is becoming more and more common.

In the gas leakage measuring device configured as described above, the first conduit system 4, the conduit 14, and the branch point 1
Conduit 11 from 7 to on-off valve 13 and branch point 18
The volume of the first container system 19 consisting of the conduit 10 from the branch point 17 to the on-off valve 9 is V ₃ , and the volume of the first container system 19 consisting of the conduit 10 from the branch point 17 to the on-off valve 13 is V 3 . , the volume of the second volume system 20 consisting of the conduit 8 from the branch point 18 to the on-off valve 7 is V ₄
It is understood that V ₄ =V ₃ +k (k: constant).

The method for measuring the amount of gas leakage according to the present invention is carried out as follows using the gas leakage amount measuring device configured as described above. First, the on-off valves 7 and 13 are opened, the on-off valve 9 is closed, and compressed air is introduced from the compressed air supply source 12 into the first container 1 and the object to be measured 3, etc., and the compressed air in the conduit 6 is When the air pressure reaches a predetermined pressure _P1 , the on-off valve 13 is closed, and the pressure measurement device 15 measures the pressure change of the compressed air in the first volume system 19. The pressure drop rate dP ₀ /dt at the time when the pressure of the compressed air in the chamber reached a predetermined pressure P ₀ (P ₀ <P ₁ ) was recorded on the recording device 16 as shown in FIG. Obtain it as the slope of the curve at pressure P ₀ from the pressure change graph. Through the above procedure, the relationship expressed by equation (1) below is determined.

(dG/dt) _P0 = (V ₁ +V ₃ +Vx)/RT・d
P ₀ /dt...(1) Similarly, the on-off valves 9 and 13 are opened and the on-off valve 7 is closed to supply air from the compressed air supply source 12 to the inside of the second container 2, the object to be measured 3, etc. Compressed air is introduced, and when the pressure of the compressed air in the conduit 6 reaches a predetermined pressure _P2 , the on-off valve 13 is closed, and the pressure of the compressed air in the second volume system 20 is measured by the pressure measuring device 15. The change is measured, and the pressure drop rate dP ₀ '/dt at the time when the pressure of the compressed air in the second volumetric system 20 reaches a predetermined pressure P ₀ is recorded using a recording device as shown in FIG. It is determined as the slope of the curve at pressure P ₀ from the graph of pressure changes recorded by No. 16. Through the above procedure, the relationship expressed by equation (2) below is determined.

(dG/dt) _P0 = (V ₂ +V ₄ +Vx)/RT・d
P ₀ /dt...(2) As mentioned above, the relationship between the volume V ₃ of the first volume system 19 and the volume V ₄ of the second volume system 20 is V ₄ =V ₃ +k (k: constant)... ...(3) exists, and even if the volumes are different, if the pressures of the gases are the same, the leakage weights (dG/dt) _P0 are the same, so these equations (1), (2), and equations ( By combining 3), the leakage amount of compressed air per unit time at the time when the pressure of compressed air inside the object to be measured 3 is _P0 is the leakage weight (dG/dt) _P0 , and the following formula ( 4) Ask for more.

According to the method and apparatus according to the present invention, the volume Vx inside the object to be measured 3 can also be determined by the following equation (5) by combining the above three equations.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited to such embodiments, and it is understood that various embodiments are possible within the scope of the present invention. It will be clear to those skilled in the art. For example, the on-off valves 7 and 9 may be replaced with switching valves provided at the branch point 18. Further, the pressures P ₁ and P ₂ of the compressed air and P ₀ may be the same value.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing one embodiment of the gas leakage measuring device according to the present invention, and Fig. 2 is a pressure P and time recorded by the recording device of the gas leakage measuring device shown in Fig. 1. It is a graph showing the relationship with t. 1... First container, 2... Second container, 3... Measured object, 4... First conduit system, 5... Second conduit system,
7... Opening/closing valve, 8... Conduit, 9... Opening/closing valve, 10, 11
... conduit, 12 ... compressed air supply source, 13 ... on-off valve,
14... Conduit, 15... Pressure measuring device, 16... Recording device, 17, 18... Branch point, 19... First volumetric system,
20...Second volumetric system.

Claims (1)

[Claims] 1. A method for measuring the amount of gas leaking from an object to be measured whose volume is Vx, which includes first and second volumes having different known volumes _V1 and _V2, respectively. a container, a first conduit having a volume of V ₃ and communicatively connecting the object to be measured and the first container to constitute a first volume system, and a volume of V ₄ to the object to be measured. a second conduit that communicates and connects the object and the second container to form a second volumetric system; and a pressurized gas source that supplies pressurized gas to the first and second volumetric systems. , a first valve device that cuts off communication between the first volumetric system and the pressurized gas source, and a second valve device that cuts off communication between the second volumetric system and the pressurized gas source. , using a gas leakage measuring device having a measuring device that continuously measures the pressure of gas in the first and second volumetric systems; the first volumetric system is formed by communicating with the container, and pressurized gas from the pressurized gas source is introduced into the first volumetric system, and the gas in the first volumetric system is When the pressure of the gas reaches a predetermined pressure _P1 , the first valve device is closed, the measuring device measures the pressure change of the gas in the first volume system, and the pressure of the gas in the first volume system is measured. The pressure drop rate dP ₀ /dt at the time when the pressure of the gas inside reaches a predetermined pressure P ₀ is determined, and the object to be measured and the second container are connected in communication through the second conduit. to form the second volumetric system, pressurized gas from the pressurized gas source is introduced into the second volumetric system, and the pressure of the gas in the second volumetric system is at a predetermined pressure. When P ₂ is reached, the second valve device is closed, and the measuring device measures the change in the pressure of the gas in the second volumetric system, and the pressure of the gas in the second volumetric system is measured. The rate of pressure decrease dP ₀ '/dt at the point when the predetermined pressure P ₀ is reached is determined, and from this, the following equations (1), (2), and (3) are simultaneously applied to the object to be measured. A method of calculating the amount of gas leaking per unit time when the pressure of the gas inside the object is P ₀ using the following formula (4) as the leakage weight (dG/dt) _P0 . (dG/dt) _P0 = (V ₁ +V ₃ +Vx)/RT・d
P ₀ /dt...(1) (dG/dt) _P0 = (V ₂ +V ₄ +Vx)/RT・d
P ₀ '/dt...(2) V ₄ =V ₃ +k (k: constant)...(3) Here, R = Gas constant T = Absolute temperature of gas 2 A device for measuring the amount of gas leaking from inside an object to be measured, comprising first and second containers having different known volumes, and the object to be measured. A first conduit that connects the object to be measured and the first container to form a first volume system; and a first conduit that connects the object to be measured and the second container to form a second volume system. A second conduit constituting the system, a pressurized gas source supplying pressurized gas to the first and second volumetric systems, and communication between the first volumetric system and the pressurized gas source. a first valve device for blocking communication between the second volumetric system and the pressurized gas source; and a second valve device for continuously measuring the pressure of the gas in the object to be measured. A device having a measuring device.