Automatic propellant supplementing method and control system

Abstract

The invention relates to the technical field of aerosol production, in particular to an automatic aerosol propellant supplementing method and a control system. The method comprises the following specific steps: S1, collecting the weight information of a liquid preparation tank, and monitoring the weight change of the liquid preparation tank in real time; s2, dynamically calculating the missing amount of the propellant, and determining the required supplementing amount; s3, triggering a supplementing instruction, and supplementing the liquid preparation tank according to the determined supplementing amount; s4, the linkage flow meter executes a supplementing program, and whether the supplementing amount is consistent with the preset amount or not is calculated; and S5, continuously filling, and repeating the steps S1-4 until the filling operation is completed. According to the invention, the weight signal of the liquid preparation tank, the propellant refilling amount and the refilling time point can be controlled through an algorithm and a program so as to automatically refill the propellant, the refilling amount is accurately controlled through the flow meter, the propellant refilling process does not need to be stopped, and the problems of large error and low efficiency of traditional propellant refilling can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of aerosol production, in particular to an automatic aerosol propellant replenishing method and a control system. Background Art

[0002] The aerosol production process is typically divided into one-step filling and two-step filling. The two-step filling process is generally not applicable to the production of suspension aerosols. Current production more often uses a one-step filling process. The common one-step filling process involves the propellant and other components (such as the active ingredient and co-solvent) being prepared together in a liquid preparation tank. The propellant and the liquid medicine are then simultaneously sealed in an aluminum can. The propellant exists in both gaseous and liquid phases within the liquid preparation tank. As the filling process progresses, the space for gaseous tetrafluoroethane continues to increase, which can cause the liquid tetrafluoroethane to volatilize, affecting the aerosol product content. Therefore, it is necessary to add propellant during the aerosol production process to ensure product content.

[0003] In aerosol production, the amount of propellant added is often manually controlled, and continuous filling is not possible during addition. Considering the volume of the liquid dispensing tank and the production batch, a single aerosol production run typically involves 3-5 additions, with each addition requiring approximately half an hour of downtime. As the amount of liquid in the dispensing tank decreases, the impact of the vaporized propellant on product content increases as the filling endpoint approaches, necessitating a higher level of precision in the amount of propellant added. Current propellant addition processes typically rely on manual control, with the endpoint determined by the dispensing tank weight. This requires that the filling process be stopped during the addition process, otherwise the determination of the addition endpoint will be affected. Summary of the Invention

[0004] The present invention aims to solve the problems existing in the background technology and to provide an automatic aerosol propellant replenishing method and control system.

[0005] The technical solution of the present invention is a method for automatically adding an aerosol propellant, comprising the following specific steps:

[0006] S1. Collect the weight information of the liquid dispensing tank and monitor the weight change of the liquid dispensing tank in real time;

[0007] S2. Dynamically calculate the amount of propellant missing and determine the required amount to be added;

[0008] S3, triggering the replenishment instruction, replenishing the liquid distribution tank according to the determined replenishment amount;

[0009] S4, the linkage flow meter executes the replenishment procedure and calculates whether the replenishment amount is consistent with the preset amount;

[0010] S5: Continue filling and repeat steps S1-4 until the filling operation is completed.

[0011] Preferably, a sensor for recording the weight of the liquid dispensing tank is installed in the liquid dispensing tank to monitor the weight change information of the liquid dispensing tank in real time and send the weight information to the PLC controller.

[0012] Preferably, the change in the gaseous propellant is calculated based on the total change in the propellant in the liquid preparation tank and the propellant physical state conversion relationship; the change in the gaseous propellant is the additional amount of propellant.

[0013] Preferably, a replenishment threshold is set, and when the calculated change in the gaseous propellant reaches the threshold, a replenishment instruction is generated by the PLC controller to replenish the liquid preparation tank.

[0014] Preferably, the replenishment threshold is calculated based on the number of replenishment times set according to product quality control requirements;

[0015] Threshold ΔWt = total amount of liquid / number of additions;

[0016] An aerosol propellant automatic replenishment control system, which is controlled using the above method, comprises:

[0017] Acquisition unit, used to collect temperature and weight data;

[0018] A storage unit for storing propellant to be added;

[0019] Temperature control unit, used to control the temperature of the liquid preparation tank and propellant storage tank;

[0020] The control unit processes the data collected by the acquisition unit, issues control instructions through the PLC controller, controls the valves on the pipeline connecting the storage unit and the liquid distribution tank, and controls the progress of the replenishment program.

[0021] Preferably, the acquisition unit includes a weight sensor and a temperature sensor;

[0022] The weight sensor is arranged in the liquid dispensing tank for real-time monitoring of the weight change of the liquid dispensing tank;

[0023] The temperature sensors are provided in plurality and are respectively located in the liquid preparation tank and the propellant storage tank, and are used for real-time monitoring of the temperature data of the liquid preparation tank and the propellant storage tank.

[0024] Preferably, the storage unit is a propellant storage tank and a liquid preparation tank;

[0025] The liquid preparation tank is used to store the prepared liquid medicine, propellant and active ingredients; and is connected to the filling equipment through a pipeline to perform an automated filling process;

[0026] The propellant storage tank is used to store propellant and is connected to the liquid dispensing tank through a pipeline to supply liquid to the liquid dispensing tank;

[0027] The lifting valve of the propellant storage tank is higher than the liquid preparation tank, and a flow control meter and a one-way check valve are installed at the end close to the liquid preparation tank of the supplement pipeline; the supplement amount of the propellant from the propellant storage tank to the liquid preparation tank is determined through the flow meter; and the check valve is used for preventing the backflow of the propellant.

[0028] Preferably, the temperature control unit is arranged on the liquid preparation tank and the propellant storage tank, and is a cold and hot all-in-one machine.

[0029] The temperature control unit is used for controlling the temperature of the liquid preparation tank and the propellant storage tank; and the temperature in the pipe of the propellant storage tank is ensured to be 3-5 ℃ higher than that of the liquid preparation tank.

[0030] Preferably, the control unit is pre-written with a control program; and the supplement amount and the supplement threshold value are calculated through the processing of the data collected by the collection unit.

[0031] When the weight change of the liquid preparation tank reaches the threshold value, the corresponding valve is controlled to be opened or closed according to the determined supplement amount, the flow meter records the supplement amount of the propellant from the propellant storage tank to the liquid preparation tank, and when the predetermined supplement amount is reached, the valve is closed to stop the supplement; and the actual supplement amount is ensured to be consistent with the predetermined supplement amount.

[0032] Compared with the prior art, the present application has the following beneficial technical effects:

[0033] One propellant storage tank of the present application completes the supplement of the propellant from the storage tank to the liquid preparation system through the control of the liquid level difference, the temperature difference and the pressure difference, and the supplement amount control is completed through the control of the liquid flow of tetrafluoroethane, so that the supplement amount can be accurately controlled. The present application can automatically supplement the propellant through the algorithm and program control of the weight signal of the liquid preparation tank, the supplement amount of the propellant and the supplement time point. The supplement amount is accurately controlled through the flow meter, and the propellant supplement process does not need to stop, so that the problems of large supplement error and low efficiency of the traditional propellant supplement can be solved. The present application integrates the flow meter and the PLC control to realize the closed loop of "detection-computation-execution". The precision and efficiency bottleneck of the traditional process is solved. The equipment used in the present application is the existing equipment, and no new equipment needs to be invested. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The figure is a flowchart of the supplement method in the embodiment of the present application.

[0035] Figure 2 The figure is a linear curve diagram of the HFA temperature and the saturated steam density in the embodiment of the present application.

[0036] Figure 3 The figure is a linear curve diagram of the HFA saturated steam density and the liquid density in the embodiment of the present application.

[0037] Figure 4 The figure is a structure diagram of the supplement system in the embodiment of the present application.

[0038] Reference numerals: 1. propellant storage tank; 2. lifting bottom valve; 3. flow meter; 4. one-way valve; 5. liquid distribution tank. DETAILED DESCRIPTION

[0039] Example 1

[0040] like Figure 1 As shown, the present invention proposes an automatic aerosol propellant replenishing method, comprising the following specific steps:

[0041] S1. Collect the weight information of the liquid mixing tank and monitor the weight change of the liquid mixing tank in real time; install a sensor for recording the weight of the liquid mixing tank in the liquid mixing tank, monitor the weight change information of the liquid mixing tank in real time, and send the weight information to the PLC controller; install temperature sensors in the liquid mixing tank and the propellant storage tank to monitor the temperature of the liquid mixing tank and the propellant storage tank in real time;

[0042] S2. Dynamically calculate the amount of propellant missing and determine the required amount to be added;

[0043] Based on the total change in propellant in the liquid dispensing tank and the physical state conversion relationship of the propellant, the change in gaseous propellant is calculated; the change in gaseous propellant is the amount of propellant to be added, and a supplementary threshold is set. When the calculated change in gaseous propellant reaches the threshold, a supplementary instruction is generated through the PLC controller to supplement the liquid dispensing tank.

[0044] The specific calculation steps are as follows:

[0045] During the filling process, the total weight of the propellant in the liquid mixing tank at the initial time and time T is defined as W t0 、W tT , the total amount of liquid propellant is W 10 、W 1T The change in the propellant in the liquid mixing tank = the change in the liquid propellant - the change in the gaseous propellant;

[0046] Formula 1: W t0 =W l0 +Va-W 10 (a / b),

[0047] Formula 2: W tT =W lT +Va-W 1T (a / b);

[0048] W t0 : The total weight of the initial propellant in the dispensing tank, the weight of the propellant in the dispensing tank at time T is = W tT (unit: kg);

[0049] W l0 : The initial weight of the liquid propellant in the mixing tank, the weight of the liquid propellant at time T is W1T (unit: kg);

[0050] V: Liquid distribution tank volume (unit: m 3 )

[0051] a: Saturated vapor density of propellant at a certain temperature (kg / m 3 )

[0052] b: Liquid density of propellant at a certain temperature (kg / m 3 )

[0053] Formula 1-Formula 2 is the change in the amount of propellant in the liquid mixing tank during the filling process (or the change in the amount of liquid in the liquid mixing tank)

[0054] Formula 3: W t0 -W tT =(W 10 -W 1T )(1-a / b),

[0055] This formula means:

[0056] 1. Total change in propellant in the mixing tank = change in liquid propellant - change in liquid propellant (a / b);

[0057] 2. Change in gaseous propellant = change in liquid propellant (a / b) = change in liquid propellant - total change in propellant in the dispensing tank;

[0058] 3. Total change in propellant in the mixing tank = (b / a) change in gaseous propellant - change in gaseous propellant;

[0059] 4. Change in gaseous propellant = total change in propellant in the mixing tank ÷ (b / a-1).

[0060] Taking tetrafluoroethane (HFA) as an example, the propellant is a=27.77kg / m at 20℃. 3 , b=1225.5kg / m 3 Substituting into the calculation, we can get:

[0061] Formula 4: Change in gaseous propellant = total change in propellant in the mixing tank ÷ 43.13

[0062] Therefore, based on the total change in the propellant in the liquid dispensing tank (the liquid dispensing tank weight sensor), the amount of propellant added (i.e. the change in the gaseous propellant) can be calculated. The linear curve of HFA temperature and saturated vapor density is as follows: Figure 2 As shown, the linear curve of HFA saturated vapor density and liquid density is as follows Figure 3 shown.

[0063] S3, triggering the replenishment instruction, replenishing the liquid distribution tank according to the determined replenishment amount;

[0064] Preferably, the replenishment threshold is calculated based on the number of replenishment times set according to product quality control requirements;

[0065] Threshold ΔWt = total amount of liquid / number of additions;

[0066] S4, the linkage flow meter executes the replenishment procedure and calculates whether the replenishment amount is consistent with the preset amount;

[0067] When the replenishment starts, the flow meter records the replenishment amount, and when the preset replenishment amount is reached, the replenishment is stopped.

[0068] S5: Continue filling and repeat steps S1-4 until the filling operation is completed.

[0069] The present invention integrates a flow meter and PLC control to realize a closed loop of "detection-calculation-execution", thus solving the accuracy and efficiency bottlenecks of traditional processes.

[0070] Example 2

[0071] This embodiment provides an aerosol propellant automatic replenishment control system, which is controlled using the method in Example 1, including:

[0072] The acquisition unit is used to collect temperature and weight data; the acquisition unit includes a weight sensor and a temperature sensor; the weight sensor is arranged in the liquid preparation tank 5 for real-time monitoring of the weight change of the liquid preparation tank 5; multiple temperature sensors are provided, respectively located in the liquid preparation tank 5 and the propellant storage tank 1, for real-time monitoring of the temperature data of the liquid preparation tank 5 and the propellant storage tank 1.

[0073] A storage unit for storing propellant to be added; the storage unit comprises a propellant storage tank 1 and a liquid preparation tank 5; the liquid preparation tank 5 is used to store prepared liquid medicine, propellant, and active ingredient; and is connected to a filling device via a pipeline for an automated filling process; the propellant storage tank 1 is used to store propellant; and is connected to the liquid preparation tank 5 via a pipeline for supplying liquid to the liquid preparation tank 5; the lifting bottom valve of the propellant storage tank 1 is higher than the liquid preparation tank 5, and a flow control meter 3 and a one-way check valve are installed on the end of the addition pipeline near the liquid preparation tank 5; the flow meter 3 determines the amount of propellant added from the propellant storage tank 1 to the liquid preparation tank 5; the check valve is used to prevent backflow of propellant.

[0074] The temperature control unit is used to control the temperature of the liquid preparation tank 5 and the propellant storage tank 1; the temperature control unit is set on the liquid preparation tank 5 and the propellant storage tank 1, and is a hot and cold integrated machine; the temperature control unit is used to control the temperature of the liquid preparation tank 5 and the propellant storage tank 1; ensure that the temperature in the propellant storage tank 1 is 3 to 5°C higher than that of the liquid preparation tank.

[0075] The control unit processes the data collected by the acquisition unit and issues control instructions via a PLC controller to control valves in the pipeline connecting the storage unit and the liquid dispensing tank 5, thereby controlling the replenishment process. The control unit is pre-programmed with a control program. By processing the data collected by the acquisition unit, the control unit calculates the replenishment amount and replenishment threshold. When the weight change of the liquid dispensing tank reaches the threshold, the control unit controls the opening and closing of the corresponding valves based on the determined replenishment amount. The flow meter records the amount of propellant added from the propellant storage tank to the liquid dispensing tank. When the predetermined replenishment amount is reached, the control unit closes the valves to stop replenishment, ensuring that the actual replenishment amount is consistent with the predetermined replenishment amount.

[0076] The following uses a specific case to introduce the content of this embodiment in detail:

[0077] like Figure 4 As shown, the entire production equipment includes the following equipment: a propellant storage tank 1, a lifting bottom valve 2, a flow meter 3, a one-way valve 4 and a liquid preparation tank 5; wherein, the propellant storage tank 1 and the liquid preparation tank 5 are both provided with a temperature control jacket; the temperature of the propellant storage tank 1 and the liquid preparation tank 5 is controlled by a cooling and heating integrated machine as a temperature control unit to ensure that the temperature in the propellant storage tank 1 is 3-5°C higher than that in the liquid preparation tank, thereby achieving a pressure in the propellant storage tank 1 higher than that in the liquid preparation tank 5, forming a pressure difference to facilitate the addition of propellant; in addition, the lifting bottom valve 2 of the propellant storage tank 1 is higher than that of the liquid preparation tank 5, which is also conducive to the addition of propellant; in this embodiment, a flow meter 3 and a one-way valve 4 are installed at one end of the addition pipeline near the liquid preparation tank 5; the flow meter 3 is used to determine the amount of propellant added from the propellant storage tank 1 to the liquid preparation tank 5; the check valve is used to prevent the backflow of propellant.

[0078] Please refer to Figure 2-3 , Figure 2-3 The linear curves of HFA temperature and saturated vapor density, HFA saturated vapor density and liquid density are given respectively, and the trend line formula is given. The PLC can calculate the amount and volume of propellant added in real time based on the actual propellant storage tank and aerosol liquid distribution system temperature control module.

[0079] Formula 5. y = 0.7635x + 13.088 (This equation is the linear relationship between HFA saturated vapor density and temperature, where x represents temperature and y represents saturated vapor density)

[0080] Formula 6. y = -4.6532x + 1357 (This equation is the linear relationship between HFA saturated vapor density and liquid density, where x represents saturated vapor density and y represents saturated vapor density)

[0081] Combining Formula 5 and Formula 6, a (saturated vapor density of the propellant at a certain temperature) and b (liquid density of the propellant at a certain temperature) at different temperatures can be derived.

[0082] Based on the original PLC control program, the propellant temperature can be further introduced as a variable into the calculation of the propellant addition amount; the addition amount can be accurately controlled.

[0083] Case 1:

[0084] Beclomethasone dipropionate inhalation aerosol

[0085] Production batch: 10,000 bottles / 141.7kg;

[0086] Liquid distribution tank capacity: 200L;

[0087] Prescription composition: tetrafluoroethane (about 88%), anhydrous ethanol and others (12%);

[0088] Liquid temperature control: 20±2℃ (at 20℃: b / a-1=43.13)

[0089] Propellant storage tank temperature control: 23℃±2℃ (liquid density at 23℃ is 1214.3kg / m 3 , calculated by formula 5 and formula 6)

[0090] Adding pipeline flow meter accuracy: ±0.5mL / min;

[0091] (1) Propellant addition process parameters:

[0092] 1. When the liquid dosage is 141.7 kg according to formula 1, 2.33 kg of tetrafluoroethane is added during feeding;

[0093] The calculation process is as follows:

[0094] Formula 1: W t0 =W l0 +Va-W 10 (a / b),

[0095] That is: W t0 =141.7×(1-0.0227)+5.55=144.03kg

[0096] Initial addition of tetrafluoroethane: 144.03-141.7kg=2.33kg

[0097] Therefore, when the liquid volume is 141.7 kg, 2.33 kg of tetrafluoroethane needs to be added to make up the gasification volume.

[0098] 2. Calculate the propellant filling process by using formula 4 when the number of tetrafluoroethane additions is fixed at 10 times.

[0099] Supplementary threshold = 141.7 ÷ 10 = 14.17 (kg),

[0100] Tetrafluoroethane gasification amount (addition amount) = 14.17 ÷ (b / a-1) = 0.327 (kg),

[0101] According to the temperature of the liquid mixing tank, a and b are adjusted in real time to calculate the vaporization amount of tetrafluoroethane propellant at different temperatures.

[0102] The flow meter controls the volume of tetrafluoroethane added each time to be 269 ml (the temperature of the tetrafluoroethane storage tank is 23°C);

[0103] That is, for every 14.17 kg weight loss of the dispensing tank, add 269 ml of tetrafluoroethane (tetrafluoroethane storage tank temperature 23°C).

[0104] (2) Propellant addition procedure:

[0105] Step 1: When the weight of the liquid dispensing tank decreases by 14.17 kg (threshold), the signal is transmitted to the PLC

[0106] Step 2: Generate propellant refill instructions

[0107] Step 3: Confirm the actual temperature of the propellant storage tank and calculate the additional volume. The flow meter is linked to the valve to control the additional acceleration rate.

[0108] Step 4: The flow meter signal is transmitted to the PLC, and the valve (check valve) is closed when the replenishment is completed;

[0109] Step 5: Continue filling without stopping the machine before and after adding.

[0110] (3) Implementation effect:

[0111] The test was carried out according to the sample content test method of beclomethasone dipropionate propellant in the "Chinese Pharmacopoeia 2025 Edition". The results of the sample content determination before and after addition are shown in Table 1 below:

[0112] Table 1 Comparison of performance tests before and after addition

[0113]

[0114] As can be seen from the table above, the aerosol sample content fluctuates little throughout the entire filling cycle. Compared with traditional manual addition, the addition accuracy is improved and production time is saved.

[0115] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A method for automatically adding an aerosol propellant, characterized in that: The specific steps include: S1. Collect the weight information of the liquid dispensing tank and monitor the weight change of the liquid dispensing tank in real time; S2. Dynamically calculate the amount of propellant missing and determine the required amount to be added; S3, triggering the replenishment instruction, replenishing the liquid distribution tank according to the determined replenishment amount; S4, the linkage flow meter executes the replenishment procedure and calculates whether the replenishment amount is consistent with the preset amount; S5: Continue filling and repeat steps S1-4 until the filling operation is completed.

2. The method for automatically adding aerosol propellant according to claim 1, characterized in that: A sensor for recording the weight of the liquid dispensing tank is installed at the bottom of the liquid dispensing tank to monitor the weight change information of the liquid dispensing tank in real time and send the weight information to the PLC controller.

3. The method for automatically adding aerosol propellant according to claim 1, characterized in that: Based on the total change in propellant in the mixing tank and the physical state conversion relationship of the propellant, the change in gaseous propellant is calculated; the change in gaseous propellant is the amount of propellant added.

4. The method for automatically adding aerosol propellant according to claim 1, characterized in that: A replenishment threshold is set. When the calculated change in the gaseous propellant reaches the threshold, a replenishment instruction is generated through the PLC controller to replenish the liquid tank.

5. The method for automatically adding aerosol propellant according to claim 4, characterized in that: Flexible setting of the number of dosing times based on product quality control requirements: a small amount of dosing in the early to mid-term of filling, and increasing the dosing frequency closer to the filling endpoint; or a fixed propellant dosing interval; The following threshold calculation is based on a fixed number of propellant additions; Threshold ΔWt = total amount of liquid prepared / number of times of addition.

6. An aerosol propellant automatic replenishment control system, which is controlled by the method according to any one of claims 1 to 5, characterized in that: include: Acquisition unit, used to collect temperature and weight data; A storage unit for storing propellant to be added; Temperature control unit, used to control the temperature of the liquid preparation tank and propellant storage tank; The control unit processes the data collected by the acquisition unit, issues control instructions through the PLC controller, controls the valves on the pipeline connecting the storage unit and the liquid distribution tank, and controls the progress of the replenishment program.

7. The aerosol propellant automatic replenishment control system according to claim 6, characterized in that: The acquisition unit includes a weight sensor and a temperature sensor; The weight sensor is arranged in the liquid dispensing tank for real-time monitoring of the weight change of the liquid dispensing tank; The temperature sensors are provided in plurality and are respectively located in the liquid preparation tank and the propellant storage tank, and are used for real-time monitoring of the temperature data of the liquid preparation tank and the propellant storage tank.

8. The aerosol propellant automatic replenishment control system according to claim 6, characterized in that: The storage unit is a propellant storage tank and a liquid preparation tank; The liquid preparation tank is used to store the prepared liquid medicine, propellant and active ingredients; and is connected to the filling equipment through a pipeline to perform an automated filling process; The propellant storage tank is used to store propellant and is connected to the liquid dispensing tank through a pipeline to supply liquid to the liquid dispensing tank; The lifting bottom valve of the propellant storage tank is higher than the liquid dispensing tank, and a flow control meter and a one-way check valve are installed on one end of the replenishing pipeline close to the liquid dispensing tank; the flow meter determines the amount of propellant added from the propellant storage tank to the liquid dispensing tank; the check valve is used to prevent the propellant from flowing back.

9. The aerosol propellant automatic replenishment control system according to claim 6, characterized in that: The temperature control unit is installed on the liquid preparation tank and the propellant storage tank, and is a hot and cold integrated machine; The temperature control unit is used to control the temperature of the liquid preparation tank and the propellant storage tank; ensuring that the temperature inside the propellant storage tank pipe is 3-5°C higher than that of the liquid preparation tank.

10. The aerosol propellant automatic replenishment control system according to claim 6, characterized in that: The control unit is pre-written with a control program; the supplementary amount and the supplementary threshold are calculated by processing the data collected by the collection unit; When the weight change of the liquid mixing tank reaches the threshold, the corresponding valve is controlled to open and close according to the determined addition amount, and the flow meter records the amount of propellant added from the propellant storage tank to the liquid mixing tank. When the predetermined addition amount is reached, the valve is closed to stop the addition; ensuring that the actual addition amount is consistent with the predetermined addition amount.

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