Intelligent storage tank sampling system

Abstract

The utility model discloses an intelligent storage tank sampling system which comprises a sampling valve, an electric pump, a sampling bottle, a sampling flow path, a sample recovery flow path and a PLC (Programmable Logic Controller), under the control of a PLC (Programmable Logic Controller), after an electromagnetic mechanism of the electric control pneumatic valve is connected with a power supply, a pneumatic executing mechanism rotates a valve core of the electric control pneumatic valve under the action of compressed gas until the valve core is at a completely-opened position, and a sample of a preset sampling point in the storage tank flows into a sampling bottle through a sampling flow path and the electric control pneumatic valve in sequence; under the control of the PLC, the electromagnetic mechanism cuts off the power supply, the pneumatic actuating mechanism drives the valve core to execute reset operation until the valve core is in a completely closed position, and the sample outlet end of the sampling flow path is cut off; and under the control of the PLC, the electric pump is started and stopped so as to replace and update the residual sample in the sample recovery flow path. Therefore, the sampling efficiency and the authenticity of sample data can be improved, and accidents caused by manual sampling are avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to an intelligent storage tank sampling system. BACKGROUND

[0002] In the production process of petrochemical industry, in order to monitor the state of liquid raw materials or products in the storage tank in real time, a small amount of liquid needs to be collected from the storage tank for chemical analysis, and the equipment specially used for collecting samples from the storage tank is called a storage tank sampler or a storage tank sampling system.

[0003] At present, the storage tank sampling system used is mostly manually collected, that is, all the valves and pumps in the sampling system are in manual operation mode. When sampling, each valve and pump needs to be manually operated by artificial. Since it is manually operated, the cycle time of the pump often cannot meet the requirement of completely replacing the residual sample, which affects the quality of sample collection.

[0004] Such sampling mode is relatively low in efficiency. Moreover, when the pipeline leaks in the manual sampling process, the sampler may be injured by the splashing liquid. INVENTION CONTENTS

[0005] The utility model aims at providing an intelligent storage tank sampling system and method, which uses a PLC controller to intelligently sample the storage tank, can improve the sampling efficiency on the one hand, and can improve the authenticity of sample data and avoid accidents caused by manual sampling on the other hand.

[0006] To achieve the above technical purpose, the utility model will adopt the following technical scheme:

[0007] An intelligent storage tank sampling system, comprising a sampling valve, an electric pump, a sampling bottle, a sampling flow path, a sample recovery flow path and a PLC controller; the sampling valve is an electric control pneumatic valve, and two normally open limit switches are arranged on the electric control pneumatic valve, which are a first limit switch and a second limit switch;

[0008] The electric control pneumatic valve is a straight-through ball valve, which has two fluid interfaces, one of which is a sample inlet, and the other of which is a sampling port; a pneumatic actuator and an electromagnetic mechanism are arranged on the valve body of the electric control pneumatic valve;

[0009] One end of the sampling flow path is a sample inlet end, and the other end is a sample outlet end; one end of the sample recovery flow path is a sample inlet end, and the other end is a sample outlet end;

[0010] The sample inlet end of the sampling flow path communicates with a preset sampling point in the storage tank, the sample outlet end of the sample recovery flow path communicates to the storage tank, the sample outlet end of the sampling flow path and the sample inlet end of the sample recovery flow path converge and communicate with the sample inlet of the electric control pneumatic valve, and the sampling bottle is arranged below the sampling port of the electric control pneumatic valve;

[0011] A motor pump is installed on the sample recovery flow path, and a one-way valve is arranged between the motor pump and the sample inlet end of the sample recovery flow path.

[0012] The electrically controlled pneumatic valve, the motor pump and the limit switch are electrically connected with the PLC controller through wires, and a first switch is connected in series on the wire between the PLC controller and the motor pump, and the electrically controlled pneumatic valve and the first switch are signal connected with the PLC controller through signal transmission lines.

[0013] Under the control of the PLC controller, when the electromagnetic mechanism of the electrically controlled pneumatic valve is connected to the power supply, the pneumatic actuator rotates the valve core of the electrically controlled pneumatic valve under the action of compressed gas, until the valve core triggers the first limit switch and causes the first limit switch to be closed, indicating that the valve core of the electrically controlled pneumatic valve is in the fully open position, and the samples at the preset sampling points in the storage tank flow into the sampling bottle through the sampling flow path and the electrically controlled pneumatic valve in turn.

[0014] Under the control of the PLC controller, when the electromagnetic mechanism is disconnected from the power supply, the pneumatic actuator drives the valve core to perform a reset operation, until the valve core triggers the second limit switch and causes the second limit switch to be closed, indicating that the valve core of the electrically controlled pneumatic valve is in the fully closed position, and the sample outlet end of the sampling flow path is cut off.

[0015] The first switch cuts off the power supply of the motor pump under the control of the PLC controller, and stops the motor pump.

[0016] The first switch connects the power supply of the motor pump under the control of the PLC controller, and the motor pump runs, and the samples at the preset sampling points in the storage tank return to the storage tank through the sampling flow path and the sample recovery flow path, realizing the replacement and update of the samples in the sampling flow path.

[0017] Preferably, the PLC controller comprises a PLC main control chip, and the PLC main control chip comprises a control module, a control panel and an indicator lamp group.

[0018] The control panel is provided with a key group, and the key group comprises a ready key; and the indicator lamp group comprises a ready indicator lamp.

[0019] The control module controls the on / off of the ready indicator lamp according to the state of the ready key.

[0020] Preferably, the key group comprises a reset key; and the control module determines whether to control the reset of the electrically controlled pneumatic valve and the motor pump according to the state of the reset key.

[0021] Preferably, the PLC main control chip is provided with a fault warning device, and the fault warning device comprises a fault alarm indicator lamp and a fault alarm buzzer.

[0022] The control module triggers a fault alarm indicator light and a fault alarm buzzer when it is determined that the electro-pneumatic valve has a fault.

[0023] Preferably, the key group comprises a mute key, and the mute key is connected with the control module.

[0024] The control module determines whether to control the fault alarm buzzer to stop sounding according to the state of the mute key.

[0025] Preferably, the key group comprises an emergency stop key, and the emergency stop key is connected with the control module.

[0026] The control module determines whether to stop continuous sampling, whether to control the electro-pneumatic valve to perform a reset operation, and whether to extinguish the ready indicator light according to the state of the emergency stop key.

[0027] Preferably, the indicator light group comprises a sampling completion indicator light and a sampling in progress indicator light, and the sampling completion indicator light and the sampling in progress indicator light are respectively connected with the control module.

[0028] The control module triggers the sampling in progress indicator light when the electro-pneumatic valve is fully opened and it is determined that sampling is formally started.

[0029] The control module triggers the sampling completion indicator light when the electro-pneumatic valve is fully closed and it is determined that sampling is ended.

[0030] Preferably, the PLC controller comprises an electrical module.

[0031] The electrical module comprises an AC / DC power conversion module, which is used to convert an input AC power supply with a voltage of 220V and a frequency of 50Hz into a DC power supply with a voltage of 24V, so as to supply power to the first switch, the electric pump, the electro-pneumatic valve, the normally closed limit switch, the control panel, the PLC control chip, the indicator light group, the key group, and the signal transmission module, respectively.

[0032] Preferably, a plurality of sampling points are arranged in the storage tank, and for each sampling point, a sampling flow path, an electro-pneumatic valve, and a sampling bottle are configured; and a sample recovery flow path is provided with a sample inlet for each sampling point; the sample inlet of each sampling flow path is communicated with the sampling point, the sample outlet is communicated with the corresponding sample inlet arranged on the sample recovery flow path after the sample inlets of the sampling flow paths are converged, and a sampling bottle is arranged below the sample inlet of each electro-pneumatic valve.

[0033] Based on the above technical purposes, compared with the prior art, the utility model has the following advantages:

[0034] 1. Improve sampling efficiency:

[0035] The utility model discloses can realize intelligent sampling, can greatly improve sampling efficiency, for example, one sampling staff every day is to collect 20 sample of storage tank, manual sampling average needs 8~10 minutes, and the utility model only needs less than 1 minute's time to complete sampling, can save 140~180 minutes's time every day.

[0036] 2, sample data high authenticity:

[0037] Manual sampling, because manual operation, the circulating time of pump often can not satisfy the requirement of completely replacing residual sample, and automatic sampling, fixed 10 minutes' circulating time can completely thoroughly replace residual medium in pipeline with the freshest sample, effectively guarantee the authenticity of the sample collected. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 It is the general view of the intelligent storage tank sampling system of the utility model;

[0039] Figure 2 It is Figure 1 The first part of the electrical schematic diagram of PLC controller in it;

[0040] Figure 3 It is Figure 1 The second part of the electrical schematic diagram of PLC controller in it;

[0041] Figure 4 It is Figure 1 The third part of the electrical schematic diagram of PLC controller in it;

[0042] Figure 5 It is Figure 1 The fourth part of the electrical schematic diagram of PLC controller in it;

[0043] Figure 6 It is Figure 1 The fifth part of the electrical schematic diagram of PLC controller in it;

[0044] Figure 7 It is Figure 1 The electrical schematic diagram of PLC controller in it. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. The description of the at least one exemplary embodiment is merely illustrative, but not as any limitation on the utility model and its application or use. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the utility model. Unless otherwise specified, the relative arrangement, expression and numerical value of the components and steps set forth in these embodiments do not limit the scope of the utility model. The technology, method and equipment known to those skilled in the related art can not be discussed in detail, but should be regarded as part of the specification under appropriate circumstances. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments can have different values.

[0046] For the convenience of description, spatial relative terms such as "above", "upper", "upper surface", "upper" and the like can be used herein to describe the spatial positional relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawing is inverted, the device described as "above" or "above" other devices or structures will be positioned "below" or "below" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations).

[0047] The basic idea of the utility model is to use a PLC controller to uniformly control an electric control pneumatic valve and an electric pump. A sampling personnel sets a fixed sampling time (for example, 9:00 am) on an operation panel (a touch screen can be used), connects a sampling bottle, presses a ready button on the operation panel, and the system enters a sampling preparation state. When the set time (9:00 am) is reached, the system starts to open the electric pump to circulate and replace the sampling flow path. After about 10 minutes of circulation, the electric pump is closed, and the electric control pneumatic valve is opened to collect the sample. The sampling time (i.e., the duration of the normal opening of the electric control pneumatic valve) is the set time (for example, 5 seconds). The electric control pneumatic valve is opened for 5 seconds and then automatically closed, and the sampling is completed. The sampling personnel directly collects the sampling bottle with the collected sample at the site, reconnects the sampling bottle, presses the ready button, and the system enters the next sampling cycle.

[0048] Because the medium inside the storage tank will settle and stratify, current petrochemical storage tank sampling, to ensure the representativeness of the collected samples, typically involves collecting samples from 3 to 5 liquid levels simultaneously, depending on the actual situation. This utility model is attached... Figure 1 The principle is illustrated using three data collection points as an example. Based on the actual needs of users, the number of data collection points can be increased or decreased according to the actual needs of users.

[0049] like Figure 1 As shown, the intelligent storage tank sampling system of this utility model includes a PLC controller, a sampling valve (the sampling valve used in this utility model is an electro-pneumatic valve, which is equipped with two normally open limit switches, corresponding to the first and second limit switches; the electro-pneumatic valve is a straight-through ball valve with two fluid interfaces, one of which is the sample inlet and the other is the sampling port. The valve body of the electro-pneumatic valve is equipped with a pneumatic actuator and an electromagnetic mechanism), an electric pump, a sampling bottle, a sampling flow path, and a sample recovery flow path.

[0050] In the electro-pneumatic valve of this invention, the valve core has two operating positions: one open and one closed. A pneumatic actuator and an electromagnetic mechanism are mounted on the valve body. The pneumatic actuator is connected to compressed gas. When the electromagnetic mechanism is powered on, the pneumatic actuator rotates the valve core under the action of the compressed gas, opening the valve. When the electromagnetic mechanism is powered off, the pneumatic actuator returns to its original position, closing the valve. Two limit switches are mounted on the pneumatic valve. When the valve core is fully open, the corresponding limit switch closes. When the valve core is fully closed, the corresponding limit switch closes. When the valve core is in an intermediate state between not fully open and not fully closed, both limit switches are open. The limit switches are designed to allow the system to determine the current state of the pneumatic valve core.

[0051] One end of the sampling flow path is the inlet, and the other end is the outlet; one end of the sample recovery flow path is the inlet, and the other end is the outlet; the inlet of the sampling flow path is connected to the preset sampling point in the storage tank, the outlet of the sample recovery flow path is connected to the storage tank, and the outlet of the sampling flow path and the inlet of the sample recovery flow path merge and are connected to the inlet of the electro-pneumatic valve. The sampling bottle is placed below the sampling port of the electro-pneumatic valve.

[0052] The intelligent tank sampling system described in the drawings can realize simultaneous sampling of samples at three different sampling points, so that the sampling flow path has three in total, and the electrically controlled pneumatic valve has three in total (corresponding to the electrically controlled pneumatic valves V1\V2\V3). For each sampling point, one sampling flow path and one electrically controlled pneumatic valve are respectively arranged, that is, when there are five sampling points, five sampling flow paths and five electrically controlled pneumatic valves need to be arranged. The sample recovery flow path has only one, but the sample recovery flow path is provided with three sample inlet ends, which are connected with the sample outlet ends of the corresponding sampling flow paths and then connected with the sample inlet of the electrically controlled pneumatic valve. One sampling bottle is arranged below the sampling port of each electrically controlled pneumatic valve. As can be seen, in the utility model, a plurality of sampling points are arranged in the tank, and for each sampling point, one sampling flow path, one electrically controlled pneumatic valve and one sampling bottle are arranged. The sample recovery flow path is provided with one sample inlet end for each sampling point. The sample inlet end of each sampling flow path is connected with the sampling point, and the sample outlet end is connected with the corresponding sample inlet end arranged on the sample recovery flow path and then connected with the sample inlet of the corresponding electrically controlled pneumatic valve. One sampling bottle is arranged below the sampling port of each electrically controlled pneumatic valve.

[0053] The electric pump is arranged on the sample recovery flow path, and a one-way valve is arranged between the electric pump and the sample inlet end of the sample recovery flow path. The one-way valve is arranged to ensure that the fluid in the sample recovery flow path can only flow in one direction.

[0054] Two limit switches are arranged on the electrically controlled pneumatic valve. One of the limit switches is used to limit the opening limit position of the valve core, and is recorded as the first limit switch. The other limit switch is used to limit the closing limit position of the valve core, and is recorded as the second limit switch. When the valve core of the electrically controlled pneumatic valve is completely in the opening position, the first limit switch is closed. When the valve core is completely in the closing position, the second limit switch is closed. When the valve core is in the intermediate state of not being completely opened and not being completely closed, both limit switches are in the disconnected state. The limit switches are arranged to facilitate the system to determine the current state of the valve core of the electrically controlled pneumatic valve.

[0055] The electrically controlled pneumatic valve, the electric pump and the limit switches are electrically connected with the PLC controller through wires, and a first switch is connected in series on the wire between the PLC controller and the electric pump. The electrically controlled pneumatic valve and the first switch are signal connected with the PLC controller through a signal transmission line. Electric power is used as the driving power of the electric pump. The PLC controller controls the opening and closing of the first switch to control the operation and stop of the electric pump. Specifically, when the first switch is closed under the control of the PLC controller, the electric pump is powered on and starts to operate. When the first switch is opened under the control of the PLC controller, the electric pump is powered off and stops operating.

[0056] Under the control of the PLC controller, the electromagnetic mechanism of the electric control pneumatic valve is connected to the power supply, and the pneumatic actuator rotates the valve core of the electric control pneumatic valve under the action of compressed gas until the valve core triggers the first limit switch and causes the first limit switch to be closed, indicating that the valve core of the electric control pneumatic valve is in the fully open position, and the samples of the preset sampling points in the storage tank flow into the sampling bottle through the sampling flow path and the electric control pneumatic valve in turn.

[0057] Under the control of the PLC controller, the electromagnetic mechanism is disconnected from the power supply, and the pneumatic actuator drives the valve core to perform a reset operation until the valve core triggers the second limit switch and causes the second limit switch to be closed, indicating that the valve core of the electric control pneumatic valve is in the fully closed position, and the sample outlet of the sampling flow path is cut off.

[0058] The first switch is controlled by the PLC controller to cut off the power supply of the electric pump, and the electric pump is stopped.

[0059] The first switch is connected to the power supply of the electric pump under the control of the PLC controller, the electric pump runs, the samples of the preset sampling points in the storage tank return to the storage tank through the sampling flow path and the sample recovery flow path, and the samples in the sampling flow path are replaced and updated.

[0060] Specifically, as shown in Figures 2-6 The PLC controller comprises an electrical module and a PLC main control chip, and the PLC main control chip comprises a control module, a control panel and a warning assembly.

[0061] The electrical module comprises an AC / DC power conversion module, which is used for converting the input AC power supply with a voltage of 220V and a frequency of 50Hz into a DC power supply with a voltage of 24V, so as to supply power to the first switch, the electric pump, the electric control pneumatic valve, the travel switch, the touch screen, the PLC control chip, the warning assembly, the key group and the signal transmission module respectively.

[0062] The warning assembly comprises an indicator light group and a fault alarm buzzer, and the indicator light assembly comprises a fault alarm indicator light (red), a ready indicator light (yellow), a sampling completion indicator light (green) and a sampling indicator light (yellow).

[0063] The control panel is provided with a key group, and the key group comprises a ready key, a reset key, a mute key and an emergency stop key.

[0064] The control module determines whether to control the electrically controlled pneumatic valve and the electric pump reset according to the state of the reset button. When the control module judges that the electrically controlled pneumatic valve has a fault, the fault alarm indicator light and the fault alarm buzzer are triggered. The control module determines whether to control the fault alarm buzzer to stop sounding according to the state of the mute button. The control module determines whether to stop continuing sampling, whether to control the electrically controlled pneumatic valve to perform a reset operation, and whether to extinguish the ready indicator light according to the state of the emergency stop button. When the electrically controlled pneumatic valve is fully opened and it is determined that sampling is formally started, the control module triggers the sampling in progress indicator light; when the electrically controlled pneumatic valve is fully closed and it is determined that sampling is completed, the control module triggers the sampling completion indicator light.

[0065] The control logic of the utility model is:

[0066] The intelligent storage tank sampling system is provided with manual and automatic modes; the manual mode can control the electric pump and each electrically controlled pneumatic valve on the MIMIC diagram.

[0067] Before starting all functions, the electrically controlled pneumatic valve is in a closed state.

[0068] The reset state of the intelligent storage tank sampling system is that the electrically controlled pneumatic valve V1, the electrically controlled pneumatic valve V2, the electrically controlled pneumatic valve V3 and the electric pump P1 are closed, the state of each electrically controlled pneumatic valve can be monitored, and the electric pump needs to be observed by naked eyes.

[0069] For the ready button and the reset button, a soft button needs to be set on the control panel while the mechanical button is set.

[0070] When the intelligent storage tank sampling system has a fault, the fault alarm indicator light is bright, the fault alarm buzzer emits an alarm sound, and the fault name is reflected on the control panel.

[0071] After the emergency stop button is pressed, sampling is stopped, and the electrically controlled pneumatic valve is controlled to reset.

[0072] After the mute button is pressed, the fault alarm buzzer stops sounding.

[0073] After the reset button is pressed, the electrically controlled pneumatic valve is controlled to reset.

[0074] After the intelligent storage tank sampling system is not operated for 5 minutes, it enters a lock screen interface; a password needs to be input to re-enter the interface. The initial password can be modified.

[0075] The intelligent storage tank sampling system can be remotely and wirelessly controlled, and all states and controls of the intelligent storage tank sampling system can be displayed on the screen of a remote system.

[0076] A fixed sampling time can be set on the control panel.

[0077] Sampling process:

[0078] Step one, place the sampling bottle under the sampling port;

[0079] In this step, since the number of electrically controlled pneumatic valves is N, denoted as electrically controlled pneumatic valve V1 to electrically controlled pneumatic valve VN, a sampling bottle is placed under the sampling port of each electrically controlled pneumatic valve;

[0080] Step two, click the ready button, and the PLC master control chip determines whether the electrically controlled pneumatic valve is reset. When the judgment result shows that the electrically controlled pneumatic valve is not reset, the PLC master control chip controls the electrically controlled pneumatic valve and the electric pump to reset until the electrically controlled pneumatic valve and the electric pump are reset (in the initial state, the electrically controlled pneumatic valve and the electric pump are in the closed state, and the reset means returning to the initial state). When the judgment result shows that the electrically controlled pneumatic valve is in the reset state, the PLC master control chip sends a first execution instruction;

[0081] Step three, under the control of the first execution instruction, the electric pump is normally started and stopped after a period of time t1 (for example, it can be preset to 1 minute), triggering the ready indicator light, and entering step three. Otherwise, under the control of the first execution instruction, the electric pump is not normally started, and the emergency stop button is pressed (it can be manually operated), and step seven is entered.

[0082] Step four, the PLC master control chip sends a second execution instruction to control the electric pump to start working and stop after a period of time t2 (which can be preset to 10 minutes) to complete the replacement of residual oil in the sampling flow path.

[0083] Step five, after the electric pump is stopped for a period of time t3 (which can be set to 1s), the PLC master control chip sends a third execution instruction. Under the control of the third execution instruction, the operation of opening the electrically controlled pneumatic valve is performed, and different operations are triggered according to whether the electrically controlled pneumatic valve fails. When the electrically controlled pneumatic valve is normally opened under the control of the third execution instruction, it indicates that the electrically controlled pneumatic valve is performing sampling, the ready indicator light is turned off, the sampling indicator light is turned on, and the timing starts, until the electrically controlled pneumatic valve is normally opened for a duration t4 that reaches a preset time t01 (which can be set to 10s) and is automatically turned off, entering step six. When the electrically controlled pneumatic valve is not normally opened under the control of the third execution instruction, and the electrically controlled pneumatic valve is in the state of not normally opened for a duration that exceeds a preset time t02 (which can be set to 5s), it indicates that the electrically controlled pneumatic valve fails, the reset button is triggered, and the fault alarm buzzer is triggered, and the fault alarm indicator light is turned on. When the electrically controlled pneumatic valve is not normally opened under the control of the third execution instruction, and the duration t5 of the state of not being opened is within the preset time t02, the timing starts from when the electrically controlled pneumatic valve is normally opened, until the electrically controlled pneumatic valve is normally opened for a duration t4 that reaches a preset time t01 and is automatically turned off, entering step six.

[0084] In this step, it needs to be particularly noted that, since the number of electrically controlled pneumatic valves has N, therefore, when all the electrically controlled pneumatic valves are normally opened, the ready indicator light is extinguished and the sampling in progress indicator light is turned on; when the duration of normal opening of all the electrically controlled pneumatic valves reaches the preset time t01, step six is entered; that is, the duration of normal opening of each electrically controlled pneumatic valve is equal.

[0085] Step six, turn off the sampling in progress indicator light and turn on the sampling completed indicator light.

[0086] Step seven, after pressing the emergency stop button, the PLC main control chip issues a fourth execution instruction; under the control of the fourth execution instruction, the electrically controlled pneumatic valve performs a reset operation, the ready indicator light is extinguished, and this information is sent out through the remote monitoring system.

Claims

1. An intelligent tank sampling system comprising a sampling valve, an electric pump, a sampling bottle, a sampling flow path, and a sample recovery flow path, characterized in that, Further comprising a PLC controller; the sampling valve is an electrically controlled pneumatic valve, and two normally open limit switches are arranged on the electrically controlled pneumatic valve, which are respectively a first limit switch and a second limit switch; The electrically controlled pneumatic valve is a straight-through ball valve, and has two fluid interfaces, one of which is a sample inlet, and the other is a sampling port; a pneumatic actuator and an electromagnetic mechanism are arranged on the valve body of the electrically controlled pneumatic valve; One end of the sampling flow path is a sample inlet end, and the other end is a sample outlet end; one end of the sample recovery flow path is a sample inlet end, and the other end is a sample outlet end; The sample inlet end of the sampling flow path is communicated with a preset sampling point in the storage tank, the sample outlet end of the sample recovery flow path is communicated to the storage tank, the sample outlet end of the sampling flow path is communicated with the sample inlet of the electrically controlled pneumatic valve after converging with the sample inlet end of the sample recovery flow path, and a sampling bottle is arranged below the sampling port of the electrically controlled pneumatic valve; An electric pump is arranged on the sample recovery flow path, and a one-way valve is arranged between the electric pump and the sample inlet end of the sample recovery flow path; the electrically controlled pneumatic valve, the electric pump and the limit switches are electrically connected with the PLC controller through wires, and a first switch is connected in series on the wires between the PLC controller and the electric pump, and the electrically controlled pneumatic valve and the first switch are signal connected with the PLC controller through signal transmission lines; Under the control of the PLC controller, after the electromagnetic mechanism of the electrically controlled pneumatic valve is connected with the power supply, the pneumatic actuator rotates the valve core of the electrically controlled pneumatic valve under the action of compressed gas, until the valve core triggers the first limit switch and makes the first limit switch closed, which indicates that the valve core of the electrically controlled pneumatic valve is in a fully open position, and the sample of the preset sampling point in the storage tank flows into the sampling bottle through the sampling flow path and the electrically controlled pneumatic valve in turn; Under the control of the PLC controller, when the electromagnetic mechanism is disconnected with the power supply, the pneumatic actuator drives the valve core to perform a reset operation, until the valve core triggers the second limit switch and makes the second limit switch closed, which indicates that the valve core of the electrically controlled pneumatic valve is in a fully closed position, and the sample outlet end of the sampling flow path is cut off; The first switch cuts off the power supply of the electric pump under the control of the PLC controller, and stops the electric pump; The first switch connects the power supply of the electric pump under the control of the PLC controller, the electric pump runs, the sample of the preset sampling point in the storage tank returns to the storage tank through the sampling flow path and the sample recovery flow path in turn, and the sample in the sampling flow path is replaced and updated.

2. The intelligent tank sampling system of claim 1, wherein, The PLC controller comprises a PLC main control chip, and the PLC main control chip comprises a control module, a control panel and an indicator lamp group; The control panel is provided with a key group, and the key group comprises a ready key; the indicator lamp group comprises a ready indicator lamp; The control module controls the on / off of the ready indicator lamp according to the state of the ready key.

3. The intelligent tank sampling system of claim 2, wherein, The key group comprises a reset key; The control module determines whether to control the reset of the electrically controlled pneumatic valve and the electric pump according to the state of the reset key.

4. The intelligent tank sampling system of claim 2 or 3, wherein, The PLC main control chip is provided with a fault warning device, and the fault warning device comprises a fault alarm indicator lamp and a fault alarm buzzer; When the control module judges that the electrically controlled pneumatic valve has a fault, the fault alarm indicator lamp and the fault alarm buzzer are triggered.

5. The intelligent tank sampling system of claim 4, wherein, The key group comprises a mute key; The mute button is connected with the control module. The control module determines whether to control the fault alarm buzzer to stop sounding according to the state of the mute button.

6. The intelligent tank sampling system of claim 2, wherein, The key group includes an emergency stop button, The emergency stop button is connected with the control module. The control module determines whether to stop continuous sampling, whether to control the electrically-controlled pneumatic valve to perform a reset operation, and whether to turn off the ready indicator according to the state of the emergency stop button.

7. The intelligent tank sampling system of claim 2, wherein, The indicator group includes a sampling completion indicator and a sampling in progress indicator, which are respectively connected with the control module. The control module triggers the sampling in progress indicator when the electrically-controlled pneumatic valve is fully opened and it is determined that sampling is formally started. The control module triggers the sampling completion indicator when the electrically-controlled pneumatic valve is fully closed and it is determined that sampling is ended.

8. The intelligent tank sampling system of claim 2, wherein, The PLC controller includes an electrical module. The electrical module includes an AC / DC power conversion module, which is used to convert the input AC power with a voltage of 220V and a frequency of 50Hz into DC power with a voltage of 24V, so as to supply power to the first switch, the electric pump, the electrically-controlled pneumatic valve, the normally-closed limit switch, the control panel, the PLC control chip, the indicator group, the key group, and the signal transmission module.

9. The intelligent tank sampling system of claim 1, wherein, A plurality of sampling points are arranged in the storage tank, and for each sampling point, a sampling flow path, an electrically-controlled pneumatic valve, and a sampling bottle are configured; and a sample recovery flow path is provided with a sample inlet for each sampling point; the sample inlet of each sampling flow path is communicated with the sampling point, the sample outlet is communicated with the corresponding sample inlet arranged on the sample recovery flow path after the sample outlet and the sample inlet are converged, and the sampling port of each electrically-controlled pneumatic valve is communicated with the corresponding sampling bottle.

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