Safety valve detection device and safety valve detection method

Abstract

The present invention provides a safety valve detection device for detecting the opening pressure of a safety valve and a safety valve detection method using the device. The safety valve detection device (100) comprises: a gas source (10); a fixed volume chamber (30) with a fixed volume connected to the safety valve to be detected; a flow controller (20) arranged between the gas source (10) and the fixed volume chamber (30) to control the flow of gas supplied from the gas source (10) to the fixed volume chamber (30); a pressure sensor (40) for detecting the pressure in the fixed volume chamber (30) and outputting pressure detection data; and a controller (50) for controlling the flow controller (20) to supply gas to the fixed volume chamber (30) at a specified flow rate, and determining the opening pressure of the safety valve according to the flow rate of gas controlled by the flow controller (20) and the pressure detection data. Thus, the opening pressure of the safety valve can be detected with simple operation and high precision.

Description

Technical Field

[0001] The invention belongs to the field of pressure detection, and in particular relates to a safety valve detection device and a safety valve detection method for detecting the opening pressure of a safety valve. Background Art

[0002] A safety valve is a safety protection valve used to protect equipment so that its internal pressure remains within a safe range. The internal cavity of the safety valve is connected to the interior of the protected equipment via a pressure tapping port. The internal cavity of the safety valve is connected to the pressure relief port of the safety valve through a controlled valve, and the pressure relief port is connected to the outside of the safety valve with a constant pressure.

[0003] The input pressure of the safety valve is the pressure of the medium at the pressure tapping port. When the input pressure is less than the opening pressure, the controlled valve is in a closed state, and the internal cavity of the safety valve is not connected to the outside. As the input pressure increases until the opening pressure is reached, the controlled valve automatically opens, and the internal cavity of the safety valve is connected to the outside through the pressure relief port, and the pressure inside the equipment is prevented from being higher or lower than the specified value by discharging / absorbing the medium to the outside. The opening and closing state of the controlled valve is also called the opening and closing state of the safety valve.

[0004] In order to check whether the safety valve can work accurately within the set pressure tolerance, it is necessary to test multiple parameters of the safety valve. One of them is the opening pressure, which refers to the input pressure when the safety valve starts to open.

[0005] Traditionally, the safety valve opening pressure is detected manually. Specifically, during the detection operation, the operator needs to adjust the input pressure of the safety valve while observing whether the safety valve is open. When the safety valve is found to be open, the pressure gauge reading is immediately recorded as the opening pressure. It is difficult to determine the opening time of the safety valve. Generally, it is done by listening to the exhaust sound of the safety valve, or by counting bubbles by immersing it in water. These methods are difficult and complicated to operate, and require readings from a pressure gauge with constantly changing readings, so the detection accuracy is not high. Summary of the invention

[0006] The present invention is made to solve the above-mentioned problems, and an object of the present invention is to provide a safety valve detection device and a safety valve detection method which are easy to operate and have high detection accuracy.

[0007] A safety valve detection device according to an embodiment of the present invention detects the opening pressure of a safety valve, and comprises: a gas supply source for providing gas; a fixed-volume chamber having a fixed volume connected to the safety valve to be detected; a flow control unit, which is arranged between the gas supply source and the fixed-volume chamber, and controls the flow of gas supplied from the gas supply source to the fixed-volume chamber in real time; a pressure sensor, which detects the pressure in the fixed-volume chamber in real time and outputs pressure detection data; and a controller, which controls the flow control unit so that the flow control unit supplies gas to the fixed-volume chamber at a specified flow rate, and determines the opening pressure of the safety valve according to the flow of gas controlled by the flow control unit and the pressure detection data.

[0008] The fixed volume chamber is a chamber with a fixed volume, which can be a separate chamber, or a pipe connecting a flow control unit and a safety valve to be tested, or the internal space of the safety valve to be tested that is not opened. The "fixed volume" mentioned here means that the volume of the chamber remains unchanged during the detection of the safety valve to be tested. In addition, the volume of the fixed volume chamber can be appropriately set according to the gas pressure of the gas supply source, the flow rate of the supplied gas, etc.

[0009] In the safety valve detection device, the flow control unit preferably supplies gas to the fixed volume chamber at a constant flow rate, and the controller calculates the opening pressure of the safety valve according to a change in pressure in the fixed volume chamber over time.

[0010] In the above-mentioned safety valve detection device, it is preferred that the flow control unit supplies gas to the above-mentioned fixed volume chamber at a variable flow rate, and the above-mentioned controller calculates the opening pressure of the above-mentioned safety valve based on the change of pressure in the above-mentioned fixed volume chamber over time and the change of the above-mentioned flow rate.

[0011] In the safety valve detection device, the controller preferably calculates the opening pressure of the safety valve based on a ratio of a rate of change of the pressure in the fixed volume chamber over time to the flow rate.

[0012] In the above safety valve detection device, it is preferred that the flow control unit is a flow controller, or a combination of a regulating valve and a flow meter.

[0013] In the above-mentioned safety valve detection device, the above-mentioned flow control unit is preferably a regulating valve, and a correspondence table representing the correspondence between the opening of the above-mentioned regulating valve and the flow rate of the gas controlled by the above-mentioned regulating valve is stored in the above-mentioned safety valve detection device. The above-mentioned controller estimates the flow rate of the gas controlled by the above-mentioned regulating valve based on the correspondence table and the opening of the above-mentioned regulating valve.

[0014] In the above safety valve detection device, it is preferred that the fixed volume chamber is a pipeline connecting the flow control unit and the safety valve to be detected.

[0015] A safety valve detection method according to an embodiment of the present invention uses the above-mentioned safety valve detection device to detect the opening pressure of the safety valve, and comprises: a gas supply step, in which the above-mentioned flow control unit supplies gas from the above-mentioned gas supply source to the above-mentioned fixed volume cavity at a prescribed flow rate, and outputs flow data; a cavity pressure detection step, in which the pressure in the above-mentioned fixed volume cavity is detected in real time, and the pressure detection data is output; and an opening pressure determination step, in which the opening pressure of the above-mentioned safety valve is determined according to the above-mentioned flow data and the above-mentioned pressure detection data.

[0016] In the above-mentioned safety valve detection method, preferably, in the above-mentioned gas supply step, gas is supplied to the above-mentioned fixed volume chamber at a constant flow rate, and in the above-mentioned opening pressure determination step, the opening pressure of the above-mentioned safety valve is calculated according to the change of pressure in the above-mentioned fixed volume chamber over time.

[0017] In the above-mentioned safety valve detection method, it is preferred that in the above-mentioned gas supply step, gas is supplied to the above-mentioned fixed volume chamber at a variable flow rate, and in the above-mentioned opening pressure determination step, the opening pressure of the above-mentioned safety valve is calculated based on the change of pressure in the above-mentioned fixed volume chamber over time and the change of the above-mentioned flow rate.

[0018] In the safety valve detection method, preferably, in the opening pressure determination step, the opening pressure of the safety valve is calculated based on the ratio of the pressure change rate in the fixed volume chamber over time to the flow rate.

[0019] In the above safety valve detection method, preferably, the fixed volume chamber is a pipeline connecting the flow control unit and the safety valve to be detected.

[0020] Effects of the Invention

[0021] In the present invention having the above structure, since the opening pressure of the safety valve can be automatically determined by the relationship curve between the pressure in the fixed volume chamber of the safety valve detection device and the flow rate and time output by the flow measurement and control unit, the process does not require manual operation by the operator, nor does it require readings from a pressure gauge with constantly changing readings. Therefore, the operation is simple, the opening pressure of the safety valve detected is highly accurate, and errors caused by human operation are few. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of the safety valve detection device according to the first embodiment of the present invention.

[0023] Figure 2 This is a flowchart of the safety valve detection method according to the first embodiment of the present invention.

[0024] Figure 3 It is a schematic diagram showing the curve of the flow rate of gas delivered to a fixed volume chamber per unit time by a flow controller at a constant flow rate over time.

[0025] Figure 4 Schematic diagram of curve C1 showing the change of pressure in a fixed volume chamber over time at a constant flow rate.

[0026] Figure 5 It is a schematic diagram showing a curve C2 of the ratio of the pressure change rate to the mass flow rate at a constant flow rate over time.

[0027] Figure 6 It is a schematic diagram showing a curve of the flow rate of gas delivered to a fixed volume chamber per unit time by a flow controller when the flow rate is changed.

[0028] Figure 7 Schematic diagram of curve C1 showing the change of pressure in a fixed volume chamber with time when the flow rate is changed.

[0029] Figure 8 Schematic diagram of a curve C2 showing how the ratio of the pressure change rate to the mass flow rate changes with time when the flow rate changes.

[0030] Fig. 9 1 is a schematic diagram showing the structure of a safety valve detection device 200 according to a second embodiment of the present invention.

[0031] Fig.10 1 is a schematic diagram of the structure of a safety valve detection device 300 according to Embodiment 3 of the present invention.

[0032] Fig.11 This is a graph showing a relationship curve between the gas flow rate detected in real time and the detection time at a constant flow rate according to Example 1 of the present invention.

[0033] Fig.12 1 is a graph showing a relationship curve between the pressure in a fixed volume chamber and the detection time at a constant flow rate according to Example 1 of the present invention.

[0034] Fig.13 It is a graph showing the change over time of the ratio of the pressure change rate in a fixed volume chamber to the gas flow rate at a constant flow rate in Example 1 of the present invention.

[0035] Fig.14 It is a graph showing a relationship curve between the gas flow rate detected in real time and the detection time when the flow rate is changed according to the second embodiment of the present invention.

[0036] Fig.15It is a graph showing the relationship between the pressure in a fixed volume chamber and the detection time when the flow rate is changed according to Example 2 of the present invention.

[0037] Fig.16 It is a graph showing the change over time of the ratio of the pressure change rate in a fixed volume chamber to the gas flow rate when the flow rate is changed in Example 2 of the present invention.

[0038] Description of Reference Numerals

[0039] 100, 200, 300 safety valve detection devices, 10 gas source, 20 flow controller, 30 fixed volume chamber, 40 pressure sensor, 50 controller, 60 safety valve, 221 regulating valve, 222 flow meter, 320 regulating valve. DETAILED DESCRIPTION

[0040] The preferred embodiments of the safety valve detection device and the safety valve detection method of the present invention are described in detail below in conjunction with the accompanying drawings and embodiments. In addition, in the description of the accompanying drawings, the same or corresponding parts are given the same symbols, and repeated descriptions are omitted.

[0041] (Implementation Method 1)

[0042] Hereinafter, the structure of the safety valve detection device 100 according to the first embodiment of the present invention will be described.

[0043] Figure 1 FIG. 1 is a schematic diagram of the structure of the safety valve detection device 100 according to Embodiment 1 of the present invention. Figure 1 As shown, the safety valve detection device 100 includes a gas source 10, a flow controller 20, a fixed volume chamber 30, a pressure sensor 40 and a controller 50. The flow controller 20, the fixed volume chamber 30 and the pressure sensor 40 are connected to each other through pipelines. The fixed volume chamber 30 of the safety valve detection device 100 is connected to the gas path of the external safety valve 60 as the detection object. The controller 50 is electrically connected to the pressure sensor 40. The pressure sensor 40 can transmit the pressure value sensed by it to the controller 50 in real time. The controller 50 analyzes the pressure value provided by the pressure sensor 40 and the flow value of the gas controlled by the flow measurement and control unit, and then obtains the opening pressure value of the safety valve 60.

[0044] The gas source 10 may be a gas pump or a nitrogen cylinder, which has a gas output interface, and the gas is supplied to the flow controller 20 via the output interface.

[0045] The flow controller 20 is a flow control unit, which adjusts the flow of gas flowing from the gas source 10 to the fixed volume chamber 30, thereby controlling the flow of gas entering the fixed volume chamber 30. The flow controller 20 has two interfaces, one interface is connected to the output interface of the gas source 10 through a connecting pipeline, and the other interface is connected to the fixed volume chamber 30 through a connecting pipeline. The flow controller 20 is also electrically connected to the controller 50. The flow controller 20 can output gas at a constant flow rate or at a variable flow rate. Since the type of gas used remains unchanged, the flow rate of the gas can be measured by mass flow rate or by volume flow rate. There is no restriction on the specific structure of the flow controller 20, as long as the gas flow control and flow acquisition functions can be achieved.

[0046] In the first embodiment, the flow controller 20 is a flow controller that can be directly purchased on the market, and the flow controller can receive the flow setting signal Q of the controller 50. r Automatically realize the gas flow Q output y control and measurement functions.

[0047] The fixed volume chamber 30 is a chamber with a fixed volume, which can be a separate chamber, or can be composed of a pipe connecting the flow controller 20 and the safety valve 60 to be tested, and can also include the internal space of the safety valve 60 that is not opened. The "fixed volume" mentioned here means that the volume of the chamber remains unchanged during the detection of the safety valve 60. For example, when the fixed volume chamber 30 is composed of a connecting pipe, the connecting pipe does not change in volume due to changes in pressure during the detection of the safety valve 60. In this embodiment 1, the fixed volume chamber 30 has interfaces connected to the flow controller 20 and the safety valve 60 respectively, and also has an interface connected to the pressure sensor 40. The shape of the internal space of the fixed volume chamber 30 is not particularly limited, and can be any shape with a fixed internal volume, such as a cube, a cuboid, a sphere or a cylinder. The fixed volume chamber 30 receives gas from the flow controller 20, and as the gas is continuously input, the pressure in the fixed volume chamber 30 continues to increase.

[0048] The pressure sensor 40 is used to detect the pressure in the fixed volume chamber 30 in real time. The pressure sensor 40 can be arranged in the fixed volume chamber 30 or outside the fixed volume chamber 30 and connected to the fixed volume chamber 30 via a pipeline interface. The pressure sensor 40 is electrically connected to the controller 50 and transmits the measured pressure in the fixed volume chamber 30 to the controller 50 in real time.

[0049] The controller 50 may be, for example, a CPU processor, which receives pressure data from the pressure sensor 40 and flow data from the flow controller 20, performs analysis to determine the state of the detection process, and provides a flow setting value to the flow controller 20 according to the analysis result. The controller 50 may also include an external interface, through which parameters of the safety valve detection device 100 may be set, and various data of the safety valve detection process may be obtained. The external interface may include a human-computer interaction interface of a keyboard and a display screen, and may also include an input and output port.

[0050] In addition, in order to improve system integration and reduce costs, the flow controller 20 and the controller 50 may be integrated into a whole and used as a flow measurement and control unit.

[0051] The safety valve 60 is not a component inside the safety valve detection device, but a detection object of the safety valve detection device 100. As a fixed parameter of the safety valve 60, there is a fixed parameter of opening pressure. When the pressure input to the safety valve 60 is less than the opening pressure of the safety valve 60, the safety valve 60 is in a closed state. When the pressure input to the safety valve 60 is greater than the opening pressure of the safety valve 60, the safety valve 60 is in an open state. When the safety valve 60 is in an open state, the gas in the fixed volume chamber 30 of the safety valve detection device 100 leaks to the outside through the safety valve 60.

[0052] Here, the working principle of the safety valve detection device 100 in the present embodiment 1 is described. The gas source 10 provides gas to the flow controller 20, and the flow controller 20 inflates the fixed volume chamber 30 according to the flow rate set by the controller 50. Among them, the controller 50 controls the flow controller 20 to output the gas flow to the fixed volume chamber 30 at a constant flow rate or a variable flow rate. When the safety valve 60 is in a closed state, as the fixed volume chamber 30 continuously receives the gas flow from the flow controller 20, the pressure increase rate in the fixed volume chamber 30 is proportional to the flow rate of the gas inflow, and the ratio of the two remains unchanged. When the pressure rises to a certain value, the safety valve 60 is opened, and a part of the gas is discharged to the outside of the fixed volume chamber 30 through the safety valve 60. At this time, the ratio of the pressure increase rate to the gas flow rate becomes smaller. The pressure sensor 40 measures the pressure in the fixed volume chamber 30 in real time, and outputs the real-time measured pressure value to the controller 50. The flow controller 20 measures the gas flow rate outputted by it in real time, and outputs the real-time measured gas flow value to the controller 50. The controller 50 calculates the opening pressure of the safety valve 60 according to the gas flow rate and pressure values ​​provided by the flow controller 20 and the pressure sensor 40 .

[0053] Hereinafter, specific steps of a safety valve detection method using the safety valve detection device 100 will be described.

[0054] Figure 2 1 is a flow chart of a safety valve detection method according to Embodiment 1 of the present invention. Figure 2 As shown, the safety valve detection method includes the following steps:

[0055] Step S1, after the fixed volume chamber 30 in the safety valve detection device 100 is connected to the gas path of the safety valve 60 to be detected, the gas source 10 is turned on, and the gas source 10 supplies gas with a certain pressure to the flow controller 20, so that the flow controller 20 supplies gas to the fixed volume chamber 30 at a specified flow rate and outputs flow data about the gas;

[0056] Step S2, enabling the pressure sensor 40 to detect the pressure in the fixed volume chamber 30 in real time and output pressure detection data; and

[0057] Step S3, using the instantaneous flow rate of the gas and the instantaneous pressure inside the fixed volume chamber 30 collected by the flow controller 20 and the pressure sensor 40 respectively, draw a curve C1 of the pressure change over time in the fixed volume chamber 30 and a curve C2 of the ratio of the pressure change rate to the flow rate over time, and determine the opening pressure of the safety valve based on the curves C1 and C2.

[0058] In addition, the safety valve detection method may further include step S4, after recording the opening pressure determined in the above step S3, changing the flow rate of the gas output by the flow controller 20 in step S2, redrawing curves C1 and C2, and determining the opening pressure of the safety valve.

[0059] The following further describes a method for determining the opening pressure of the safety valve by causing the flow controller 20 to output gas at a constant flow rate and a variable flow rate.

[0060] (Method for measuring constant flow rate)

[0061] Figure 3 It is a schematic diagram showing a curve of the flow rate of gas delivered to the fixed volume chamber 30 per unit time by the flow controller 20 at a constant flow rate over time. Figure 3 Q(t) means the amount of gas delivered to the fixed volume chamber 30 by the flow controller 20 per unit time, i.e., the instantaneous flow rate. The flow rate can be measured by volume flow rate or mass flow rate as described above. In the case of a constant flow rate, the volume or mass of gas delivered to the fixed volume chamber 30 by the flow controller 20 per unit time is a constant value, i.e., Q c . Figure 3 It shows that under the condition of constant flow rate, Q(t) changes with time to a constant value.

[0062] Figure 4is a schematic diagram showing a curve C1 of the pressure in the fixed volume chamber 30 changing with time at a constant flow rate. Figure 4 As shown, when the flow controller 20 outputs air flow to the fixed volume chamber 30 at a constant flow rate, the relationship between the pressure in the fixed volume chamber 30 and time is a straight line with a fixed slope, and the slope of the straight line represents the rate of increase of the pressure in the fixed volume chamber 30. As the pressure in the fixed volume chamber 30 gradually increases, when the pressure in the fixed volume chamber 30 reaches the opening pressure of the safety valve 60, the safety valve 60 switches from a closed state to an open state. At this time, the gas in the fixed volume chamber 30 leaks to the outside through the safety valve 60, and then the rate of increase of the pressure in the fixed volume chamber 30 decreases. In the case of a constant flow rate, the opening pressure of the safety valve 60 can be directly judged by the curve of the pressure in the fixed volume chamber 30 changing with time. Specifically, in Figure 4 As time goes by, the pressure curve is initially a straight line with a fixed slope. When the safety valve 60 is opened and the gas is discharged, the slope of the pressure curve decreases, but the pressure continues to increase. Figure 4 An extension line of the initial straight line is drawn in the figure, and its tangent point with the second half of the pressure curve is the point at which the safety valve 60 opens. The time t0 corresponding to this point is the time when the safety valve 60 opens, and the pressure P0 corresponding to this point is the opening pressure of the safety valve 60.

[0063] Figure 5 It is a schematic diagram showing a curve C2 of the ratio of the pressure change rate to the flow rate at a constant flow rate over time. Figure 5 R(t) in the formula represents the ratio of the pressure change rate to the flow rate, which is calculated by the following formula (1).

[0064]

[0065] Wherein, P(t) represents the pressure in the fixed volume chamber 30 at time t.

[0066] In the case of constant flow, R(t) is a constant value, that is, R c When the pressure in the fixed volume chamber 30 reaches the opening pressure of the safety valve 60, the safety valve 60 switches from the closed state to the open state. At this time, the curve of R(t) changing with time will decrease, and an inflection point will be generated. The time t when this inflection point is generated is o This is the moment when the safety valve 60 switches from the closed state to the open state. Figure 3 Determine the time t o The corresponding pressure P0 in the fixed volume chamber 30 is the opening pressure of the safety valve 60 .

[0067] (Method for measuring variable flow rate)

[0068] Figure 6 It is a schematic diagram showing a curve of the flow rate of gas delivered to the fixed volume chamber 30 per unit time by the flow controller 20 when the flow rate is changed. Figure 6 Q(t) means the amount of gas delivered to the fixed volume chamber 30 by the flow controller 20 per unit time, i.e., the instantaneous flow rate, which can be measured by volume flow rate or mass flow rate as described above. When the flow rate is a variable flow rate, the change of the flow rate over time is irregular, and it can be a curve of any shape.

[0069] Figure 7 is a schematic diagram showing the curve C1 of the pressure change over time in the fixed volume chamber 30 when the flow rate changes. Figure 7 As shown, when the flow controller 20 outputs the air flow to the fixed volume chamber 30 at a variable flow rate, the pressure in the fixed volume chamber 30 gradually increases over time, but the rate of increase, i.e., the slope, is not fixed. Therefore, the relationship between the pressure in the fixed volume chamber 30 and time is a curve with a gradually increasing slope and a non-fixed slope. In the case of a variable flow rate, for example, Figure 7 The opening pressure of the safety valve 60 is determined by the tangent point of the second half of the pressure curve in , but in order to further improve the accuracy, it is preferred to use the following curve of the ratio of the pressure change rate to the flow rate over time to determine the opening pressure of the safety valve.

[0070] Figure 8 Schematic diagram of a curve C2 showing how the ratio of the pressure change rate to the flow rate changes over time when the flow rate changes. Figure 8 R(t) in the formula represents the ratio of the pressure change rate to the flow rate, which is calculated by the following formula (2).

[0071]

[0072] Wherein, P(t) represents the pressure in the fixed volume chamber 30 at time t.

[0073] Since the fixed volume chamber 30 with a fixed volume is inflated, R(t) is also a constant value under the condition of variable flow rate, that is, R c When the pressure in the fixed volume chamber 30 reaches the opening pressure of the safety valve 60, the safety valve 60 switches from the closed state to the open state. At this time, the curve of R(t) changing with time will decrease, and an inflection point will be generated. The time t when this inflection point is generated is o This is the moment when the safety valve 60 switches from the closed state to the open state. Figure 6 Determine the time t o The corresponding pressure P0 in the fixed volume chamber 30 is the opening pressure of the safety valve 60 .

[0074] According to one embodiment of the present invention described above, since the opening pressure of the safety valve 60 can be automatically determined by the relationship curve between the pressure in the fixed volume chamber 30 of the safety valve detection device 100 and the flow rate output by the flow controller 20 and time, the process does not require manual operation by the operator, nor does it require readings from a pressure gauge with constantly changing readings. Therefore, the operation is simple, the opening pressure of the detected safety valve is highly accurate, and the errors caused by human operation are small.

[0075] In addition, the safety valve detection device 100 may also include a human-machine interface electrically connected to the controller 50, and the opening pressure value of the safety valve 60 can be displayed on the human-machine interface. Thus, the opening pressure of the safety valve 60 can be directly read on the human-machine interface of the safety valve detection device 100, or can be obtained via a data interface, so that the safety valve detection device 100 can provide the opening pressure of the safety valve 60 more intuitively and conveniently. In addition, the user can also use the human-machine interface to input various parameters for detection, such as the initial pressure of the gas source 10, the initial flow rate of the supplied gas, and whether to use a constant flow rate or a variable flow rate for detection, etc., and the detection of the safety valve detection device 100 can be controlled via the controller 50.

[0076] (Implementation Method 2)

[0077] In the above embodiment 1, the safety valve detection device 100 having the flow controller 20 and the detection method using the same are described. Different from the embodiment 1, in the present embodiment 2, as a flow control unit, a combination of a regulating valve and a flow meter is used instead of the flow controller 20. That is, in the present embodiment 2, as a flow control unit, a regulating valve and a flow meter are used. The remaining structure is the same as that of the embodiment 1, and the description is omitted here.

[0078] Fig. 9 FIG. 2 is a schematic diagram of the structure of a safety valve detection device 200 according to Embodiment 2 of the present invention. Fig. 9 As shown, the safety valve detection device 200 is different from the safety valve detection device 100 of embodiment 1 in that it has a regulating valve 221 and a flow meter 222 as a flow control unit. The regulating valve 221 and the flow meter 222 are electrically connected to the controller 50, respectively, and the regulating valve 221 is also connected to the pipeline of the gas source 10 and the fixed volume chamber 30. The flow meter 222 can measure the flow rate Q of the gas output from the regulating valve 221. y The regulating valve 221 receives the opening signal u transmitted from the controller 50 and changes the opening degree. The regulating valve 221 can be an on-off valve or a proportional valve. The controller 50 automatically adjusts the on-off ratio or opening ratio of the regulating valve 221 according to the feedback of the flow meter 222 to make the gas flow Q yThe requirements of the safety valve detection method in implementation mode 1 are met.

[0079] In the second embodiment, the opening pressure of the safety valve 60 can be determined by the same method as the safety valve detection method described in the first embodiment.

[0080] According to the second embodiment, the same technical effects as those of the first embodiment can be obtained.

[0081] (Implementation 3)

[0082] In the above embodiment 1, the safety valve detection device 100 having the flow controller 20 and the detection method using the same are described. Different from the embodiment 1, in the present embodiment 3, as a flow control unit, a single regulating valve is used instead of the flow controller 20. The remaining structure is the same as that of the embodiment 1, and the description is omitted here.

[0083] Fig.10 FIG. 3 is a schematic diagram of the structure of a safety valve detection device 300 according to Embodiment 3 of the present invention. Fig.10 As shown, the safety valve detection device 300 is different from the safety valve detection device 100 of embodiment 1 in that it has a regulating valve 320 as a flow control unit. The regulating valve 320 can be an on-off valve or a proportional valve. The regulating valve 320 is electrically connected to the controller 50, and is connected to the pipeline of the gas source 10 and the fixed volume chamber 30. The regulating valve 320 is controlled by the controller 50, and the controller 50 can control the opening degree of the regulating valve to adjust the flow of gas passing through the regulating valve 320. In this embodiment 3, it is necessary to model the characteristics of the regulating valve 320 in advance, so that the flow rate actually output by the regulating valve 320 can be obtained by calculation based on the opening degree of the regulating valve 320 and the pressure at both ends of the regulating valve 320. The controller 50 calculates and obtains the flow rate of the gas through the operating state of the regulating valve 320. That is, a correspondence table showing the correspondence between the opening of the regulating valve 320 and the flow rate of the gas controlled by the regulating valve 320 is stored in the safety valve detection device 300, and the controller 50 estimates the flow rate of the gas controlled by the regulating valve 320 based on the correspondence table and the opening of the regulating valve 320.

[0084] In the third embodiment, the opening pressure of the safety valve 60 can be determined by the same method as the safety valve detection method described in the first embodiment.

[0085] According to the third embodiment, the same technical effects as those of the first embodiment can be obtained.

[0086] (Example 1)

[0087] Below, use Figure 11 to Figure 13An embodiment of actually using the safety valve detection device of the present invention to detect the opening pressure of a safety valve is described below.

[0088] In this embodiment 1, the safety valve detection device 100 of embodiment 1 is used to detect the opening pressure of the safety valve by a constant flow measurement method. The fixed volume chamber 30 is composed of a gas volume and a pipeline connecting the flow control unit and the safety valve to be tested, and the total volume is 300mL. As described above, in the safety valve detection device 100, a flow controller 20 is used as a flow control unit, which can automatically realize the control and measurement functions of the gas flow outputted thereto.

[0089] In the present embodiment 1, after the safety valve detection device 100 is connected to the gas path of the safety valve 60 to be detected, the gas source 10 is turned on, and the gas source 10 supplies gas with a certain pressure to the flow controller 20. The flow controller 20 maintains the flow rate of the gas output to the fixed volume chamber 30 at a substantially constant value according to the control signal of the control unit. The initial pressure of the gas supplied by the gas source 10 is approximately 723 KPa, and the detection time is approximately 50 seconds.

[0090] Fig.11 The graph shows the relationship between the gas flow rate supplied to the fixed volume chamber 30 and the detection time detected in real time by the flow controller 20. Fig.11 It can be seen that the flow rate measured by the flow controller 20 remains substantially constant over time, that is, substantially maintained at 6 liters per minute (NLPM).

[0091] Fig.12 The curve represents the relationship between the pressure in the fixed volume chamber 30 detected by the pressure sensor 40 in real time and the detection time. Fig.12 It can be seen that the pressure in the fixed volume chamber 30 gradually increases as the gas is continuously supplied, and the rate of increase, i.e., the slope, is approximately the same, which is caused by the fact that the gas flow rate supplied to the fixed volume chamber 30 is approximately constant. In addition, when the pressure in the fixed volume chamber 30 reaches a certain value, it decreases, and then remains at an approximately fixed value as time changes, which is believed to be caused by the safety valve 60 switching from a closed state to an open state. Therefore, according to Fig.12 The relationship curve in can also roughly determine the opening pressure of the safety valve 60, that is, the pressure value when the pressure in the fixed volume chamber 30 begins to drop, that is, the pressure value at the inflection point can be determined as the opening pressure of the safety valve.

[0092] In addition, in order to further improve the accuracy, the opening pressure of the safety valve can also be determined by the following curve of the ratio of the pressure change rate to the flow rate over time.

[0093] Fig.13The ratio of the pressure change rate in the fixed volume chamber 30 to the flow rate measured by the flow controller 20 changes over time. Fig.11 and Fig.12 The measurement results in are obtained by calculating the above formula (1).

[0094] according to Fig.13 It can be seen that the ratio of the pressure change rate to the flow rate does not change at first, but when it reaches the 19.14th second of the detection time, the ratio of the pressure change rate to the flow rate decreases sharply. The sharp decrease in the ratio of the pressure change rate to the flow rate is considered to be caused by the safety valve 60 switching from the closed state to the open state, so it can be considered that the safety valve 60 is opened at the 19.14th second of the detection time, that is, the opening time t0 is determined to be 19.14 seconds.

[0095] Next, according to Fig.12 From the relationship curve between pressure and detection time shown, it can be determined that the pressure value corresponding to the opening time t0 is 507.7 KPa, and this pressure value is determined as the opening pressure P0 of the safety valve 60 .

[0096] exist Fig.13 In the embodiment, as the safety valve 60 switches from the closed state to the open state, the ratio of the pressure change rate to the flow rate decreases sharply. Fig.12 The curve shown can more easily and accurately identify the time when the safety valve 60 switches from the closed state to the open state, and the opening pressure P0 of the safety valve 60 determined based on this time is also more accurate.

[0097] In addition, since the gas flow supplied to the fixed volume chamber 30 is kept approximately constant in the constant flow measurement method of Example 1, even if the ratio of the pressure change rate to the flow measured by the flow controller 20 is not used, but only the pressure change rate is used, the opening pressure P0 of the safety valve 60 can be detected approximately the same.

[0098] (Example 2)

[0099] Below, use Figure 14 to Figure 16 An embodiment of actually using the safety valve detection device of the present invention to detect the opening pressure of a safety valve is described below.

[0100] In this embodiment 2, the safety valve detection device 200 of embodiment 2 is used to detect the opening pressure of the safety valve by measuring the variable flow rate. The fixed volume chamber 30 is also composed of an air volume and a pipeline connecting the flow control unit and the safety valve to be tested, and the total volume is 300mL. As described above, the safety valve detection device 200 of embodiment 2 uses a regulating valve 221 and a flow meter 222 as a flow control unit.

[0101] In the present embodiment 2, after the safety valve detection device 200 is connected to the gas path of the safety valve 60 to be detected, the gas source 10 is turned on, and the gas source 10 supplies gas with a certain pressure to the regulating valve 221, and the flow meter 222 measures the flow rate of the gas output from the regulating valve 221 to the fixed volume chamber 30. Among them, the initial pressure of the gas supplied by the gas source 10 is approximately 646 KPa, the initial valve opening of the regulating valve 221 is 0.460, and the detection time is approximately 50 seconds.

[0102] Fig.14 The graph shows the relationship between the gas flow rate supplied to the fixed volume chamber 30 and the detection time detected by the flow meter 222 in real time. Fig.14 It can be seen that the flow rate measured by the flow meter 222 changes with time.

[0103] Fig.15 The curve represents the relationship between the pressure in the fixed volume chamber 30 detected by the pressure sensor 40 in real time and the detection time. Fig.15 It can be seen that the pressure in the fixed volume chamber 30 gradually increases as the gas is continuously supplied, and the rate of increase, i.e., the slope, is not fixed, which is caused by the continuous change in the gas flow rate supplied to the fixed volume chamber 30. In addition, when the pressure in the fixed volume chamber 30 reaches a certain value, it drops, and then remains at a roughly fixed value as time changes, which is believed to be caused by the safety valve 60 switching from a closed state to an open state. Therefore, according to Fig.15 The relationship curve in can also roughly determine the opening pressure of the safety valve 60, that is, the pressure value when the pressure in the fixed volume chamber 30 begins to drop, that is, the pressure value at the inflection point, can be determined as the opening pressure of the safety valve.

[0104] In addition, in order to further improve the accuracy, the opening pressure of the safety valve can also be determined by the following curve of the ratio of the pressure change rate to the flow rate over time.

[0105] Fig.16 The ratio of the pressure change rate in the fixed volume chamber 30 to the flow rate measured by the flow meter 222 changes over time. Fig.14 and Fig.15 The measurement results in are obtained by calculating the above formula (2).

[0106] according to Fig.16It can be seen that the ratio of the pressure change rate to the flow rate does not change at first, but when it reaches the 32.22 second of the detection time, the ratio of the pressure change rate to the flow rate decreases sharply. The sharp decrease in the ratio of the pressure change rate to the flow rate is considered to be caused by the safety valve 60 switching from the closed state to the open state, so it can be considered that the safety valve 60 is opened at the 32.22 second of the detection time, that is, the opening time t0 is determined to be 32.22 seconds.

[0107] Next, according to Fig.15 The relationship curve between pressure and detection time shown in the figure can determine that the pressure value corresponding to the opening time t0 is 499.74 KPa, and this pressure value is determined as the opening pressure P0 of the safety valve 60.

[0108] exist Fig.16 In the embodiment, as the safety valve 60 switches from the closed state to the open state, the ratio of the pressure change rate to the flow rate decreases sharply. Fig.15 The curve shown can more easily and accurately identify the time when the safety valve 60 switches from the closed state to the open state, and the opening pressure P0 of the safety valve 60 determined based on this time is also more accurate.

[0109] According to the above embodiments 1 and 2, the safety valve detection device of the present invention does not require manual operation by an operator during the detection process, nor does it require readings from a pressure gauge whose readings are constantly changing. The opening pressure of the safety valve can be detected easily and with high accuracy.

[0110] In the above embodiments 1 and 2, the safety valve detection device 100 with a flow controller 20 of embodiment 1 and the safety valve detection device 200 with a regulating valve 221 and a flow meter 222 of embodiment 2 are used to detect the opening pressure of the safety valve. However, those skilled in the art know that the same technical effect can be obtained by using a safety valve detection device 300 with a regulating valve 320 and a corresponding table indicating the corresponding relationship between the opening of the regulating valve and the gas flow rate.

[0111] In addition, in the above embodiments 1 and 2, the fixed volume chamber is composed of a gas volume and a pipeline connecting the flow control unit and the safety valve to be tested, but the present invention is not limited thereto, and the fixed volume chamber can also be composed of only a pipeline connecting the flow control unit and the safety valve to be tested, so that the safety valve detection device can be miniaturized. In addition, the volume of the fixed volume chamber is not particularly limited, and can be appropriately set according to the gas pressure of the gas supply source, the flow rate of the supplied gas, etc., as long as it remains unchanged during the detection process of the safety valve to be tested.

[0112] The present invention is not limited to the above-mentioned embodiments, but includes various variations. The above-mentioned embodiments are detailed descriptions for the purpose of explaining the present invention in a simple and understandable manner, and are not limited to all structures described. In addition, the structures and connection methods of each component are not limited thereto, and any equivalent transformations and improvements based on the technical solution of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A safety valve detection device for detecting the opening pressure of a safety valve, characterized in that: include: a gas supply source for providing gas; A fixed volume chamber having a fixed volume connected to the safety valve under test; A flow control unit, which is disposed between the gas supply source and the fixed volume chamber, and controls the flow of the gas supplied from the gas supply source to the fixed volume chamber in real time; A pressure sensor detects the pressure in the fixed volume chamber in real time and outputs pressure detection data; and a controller, which controls the flow control unit to make the flow control unit supply gas to the fixed volume chamber at a specified flow rate, and determines the opening pressure of the safety valve according to the flow rate of the gas controlled by the flow control unit and the pressure detection data; The flow control unit supplies gas to the fixed volume chamber at a constant flow rate, and the controller calculates the opening pressure of the safety valve according to the change of the pressure in the fixed volume chamber over time. As time goes by, the initial section of the pressure curve is a straight line with a fixed slope, and the slope of the second half of the pressure curve decreases. The tangent point of the extended line of the initial section of the pressure curve and the second half of the pressure curve is the point where the safety valve is opened, and the pressure corresponding to this point is the opening pressure of the safety valve; or, supplying gas from the flow control unit to the fixed volume chamber at a constant flow rate, the controller calculating the opening pressure of the safety valve according to the ratio of the rate of change of the pressure in the fixed volume chamber over time to the flow rate; or, The flow control unit supplies gas to the fixed volume chamber at a variable flow rate, and the controller calculates the opening pressure of the safety valve according to the ratio of the change rate of the pressure in the fixed volume chamber over time to the flow rate.

2. The safety valve detection device according to claim 1, characterized in that: supplying gas from the flow control unit to the fixed volume chamber at a variable flow rate, The controller calculates the opening pressure of the safety valve according to the change of the pressure in the fixed volume chamber over time and the change of the flow rate; When the ratio of the rate of change of the pressure in the fixed volume chamber with time to the flow rate changes from a constant value to a decrease, an inflection point is generated. The moment when the inflection point is generated is the moment when the safety valve switches from a closed state to an open state. The pressure in the fixed volume chamber corresponding to this moment is the opening pressure of the safety valve.

3. The safety valve detection device according to any one of claims 1 to 2, characterized in that: The flow control unit is a flow controller, or a combination of a regulating valve and a flow meter; The regulating valve and the flow meter are electrically connected to the controller respectively. The regulating valve pipeline is connected between the gas supply source and the fixed volume chamber. The flow meter measures the flow of the gas output from the regulating valve. The regulating valve receives the opening signal transmitted from the controller and changes the opening degree. The controller automatically adjusts the switching ratio or opening ratio of the regulating valve according to the feedback of the flow meter.

4. The safety valve detection device according to any one of claims 1 to 2, characterized in that: The flow control unit is a regulating valve. A correspondence table showing a correspondence between the opening of the regulating valve and the flow rate of the gas controlled by the regulating valve is stored in the safety valve detection device. The controller estimates the flow rate of the gas controlled by the regulating valve based on the correspondence table and the opening degree of the regulating valve.

5. The safety valve detection device according to any one of claims 1 to 2, characterized in that: The fixed volume chamber is a pipeline connecting the flow control unit and the safety valve to be tested.

6. A safety valve detection method for detecting the opening pressure of a safety valve, using the safety valve detection device according to any one of claims 1 to 5 for detection, the safety valve detection method being characterized by comprising: a gas supply step, causing the flow control unit to supply gas from the gas supply source to the fixed volume chamber at a prescribed flow rate and output flow rate data; a cavity pressure detection step, detecting the pressure in the fixed volume cavity in real time and outputting pressure detection data; and The opening pressure determination step is to determine the opening pressure of the safety valve according to the flow data and the pressure detection data.

7. The safety valve detection method according to claim 6, characterized in that: In the gas supplying step, gas is supplied to the fixed volume chamber at a constant flow rate, In the opening pressure determination step, the opening pressure of the safety valve is calculated according to the change of the pressure in the fixed volume chamber over time.

8. The safety valve detection method according to claim 6, characterized in that: In the gas supplying step, gas is supplied to the fixed volume chamber at a variable flow rate, In the opening pressure determination step, the opening pressure of the safety valve is calculated according to the change of the pressure in the fixed volume chamber over time and the change of the flow rate.

9. The safety valve detection method according to claim 7 or 8, characterized in that: In the opening pressure determination step, the opening pressure of the safety valve is calculated according to the ratio of the change rate of the pressure in the fixed volume chamber over time to the flow rate.

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