WO2021096477A2

WO2021096477A2 - An air generator control system and operation method used in compressed air generators for intermittent air consumed systems

Info

Publication number: WO2021096477A2
Application number: PCT/TR2020/051102
Authority: WO
Inventors: Nihat CANKAYA; Muciz OZCAN
Original assignee: Cankaya Nihat
Priority date: 2019-11-13
Filing date: 2020-11-13
Publication date: 2021-05-20
Also published as: WO2021096477A3

Abstract

The invention relates to a new "air generator control device and algorithm", which can be used in all compressed air generators that supply air to places where the air is consumed at intermittent and has a programmable microcontroller card to have advanced control algorithms.

Description

AN AIR GENERATOR CONTROL SYSTEM AND OPERATION METHOD USED IN COMPRESSED AIR GENERATORS FOR INTERMITTENT AIR CONSUMED

SYSTEMS

FIELD OF INVENTION

The invention relates to a new "air generator control device ", which can be used in all compressed air generators that supply air to places where the intermittent air consumed and includes a programmable microcontroller card to have advanced control algorithms.

BACKGROUND

Compressed air at different pressure values is used in the industry. Generally, the type of air generator changes according to the pressure range of the air to be used. The current compressed air supply method is to produce the air at the required pressure and keep it ready at that pressure. Compressed air at different pressure values is used in the industry. Generally, the type of air generator changes according to the pressure range of the air to be used. The current compressed air supply method is to produce the air at the required pressure and keep it ready at that pressure. And it is continued to air production in a way that the pressure value does not decrease further. If air consumption decreases, three different ways are followed. Air production is continued by throwing excess air outside or air production is continued by reducing the airflow or the air compressor is stopped for a while by reaching a pressure higher than the need. In this air production method, although dynamic control of the airflow can be made to increase system efficiency, the pressure value remains constant or is realized above the need. Currently, it is assumed that there is continuous air consumption in all systems. However, in industry, in addition to the systems that consume air continuously, systems that use only intermittent air and at a constant airflow are also widely used. The current air generation method is not very suitable for places that consume air at regular intervals. Because, even when the air is not demanded, the standby of the air generator at a certain pressure causes warming and extra energy consumption. The working temperature of the air generator depends on the pressure, the energy consumption depends on both pressure and airflow. Especially, systems in which the pressure is tried to be kept constant by throwing the excess air produced out of a discharge valve are quite inefficient. In such systems, a timer is used to reduce the time exposed to high pressure. Air is produced for a long time to guarantee that the pressure reaches the desired value, while the excess air continues to be discharged from the release valve. When the set time comes, all air is supplied to the system. The duration the air is delivered to the system is also done with the help of a timer. Flowever, in this method, neither the right moment when the air should be supplied to the system nor the duration the air should be delivered to the system cannot be determined exactly. In these systems, both the air generator produces air at a higher airflow than needed and is constantly exposed to the highest air pressure value.

In all current production methods, the pressure value is always constant and close to the required value, and it cannot be taken down. Flowever, the pressure parameter is the main parameter that determines the values such as operating temperature, energy consumption, oil temperature, oil life, wear, equipment life.

LIST OF FIGURES

Figure 1. The Device and the Intermittent Air Consumption System Where the Device Will Be Used

Figure 2. The Change of the Counter-Pressure Values When the Air Generator Is Operated In a Classical Way, For the Same Air Consumption System.

Figure 3. The Change of the Counter-Pressure Values When the Air Generator Is Operated Using the Method Offered By the Newly Developed Device, For the Same Air Consumption System.

Description of the Numbers Given in Figures

1. Device

2. Driver of electric motor

3. Electric motor

4. Power transmission system

5. Compressed air generator

6. Relief valve

7. Air tank

8. Pressure transmitter 9. Solenoid valve

10. Transmitter for air demand detecting

11. Display

12. Keyboard 13. Micro controller

14. Analog inputs

15. Digital inputs

16. Analog outputs

17. Digital outputs 18. Relay outputs

19. Pulse outputs

20. Industrial communication modules

21. Pulse width modulation modules

22. Stepping motor driver modules 23. Wireless communication modules

24. Power inputs

25. Programmable logic controller modules

26. A box to protect the device from external influences BRIEF DESCRIPTION OF THE INVENTION

Invention is a new controller that includes a microcontroller card that can be programmed to execute advanced control algorithms. This device was developed to control compressed air generators that supply air to places that consume air periodically (periodically). It is also used in vacuum generators in systems that consume periodic vacuum. Thanks to its algorithm, the device offers a new way of working. Operating temperature of the air generator; depends on the average pressure the air generator is exposed to. The energy consumption of the air generator depends on both the average pressure the air generator is exposed to and the average airflow of the air generator. The new method allows you to create a new method providing dynamic control over pressure and airflow; it lowers both the average air pressure the air generator is exposed to and the average airflow that needs to be produced. In this way, compressed air reduces both the operating temperature and energy consumption of the generator. This method also lowers the level of noise caused by the air generator. DETAILED DESCRIPTION OF THE INVENTION

A new method and a device (1) that implements this method have been developed unlike the methods used in the previous technique for air generators (5) used in places that consume intermittent air. The method offered by this device (1) provides dynamic control of both the airflow and pressure parameter, instead of today's compressed air production methods, which only provide dynamic control over the airflow.

With this method, the average pressure value of the air generator (5) is much less than the pressure value used by the air consuming system. In the same method, the average airflow of the air generator (5) decreases only to the airflow value required by the system, and there is no air thrown out of the relief valve (6) to keep the pressure constant.

Reduction of average air pressure; reduces the operating temperature and energy consumption of the air generator (5). Thanks to the decreasing operating temperature, oil life, bearing life and the life of other equipment are longer. The amount of waste oil is decreased. The average air pressure the air generator (5) is exposed to is less than half the pressure of the air consumed in the new method, while equal to the air consumed in today's classical method. The decrease in average airflow reduces energy consumption. Reducing the average air pressure value decreases the level of noise caused by the air generator (5). The noise level of the system is also reduced because there is no air evacuated from any relief valve in the system to keep the pressure constant.

The reason for the decrease in average air pressure is the new air production method offered by the algorithm of the device (1). This method may use at the intermittent air consumed systems that its air generator (5) could not be stopped. This method is defined as keeping the air pressure at the lowest possible value until the system requests air, increasing the pressure by close to the moment of air demanding, reaching the highest pressure value at the moment of air use. Then, the pressure is decreased to the lowest value again by all the air in the tank (7) is given to the system. The aim is to increase the time the air generator (5) is exposed to low pressure during a consumption period and to decrease the time it is exposed to high pressure.

The difference between the classical method and the new method provided by the device (1) is seen in Figure 2 and Figure 3. This curve shows the change in air pressure in the air tank (7) depending on the time. The area below this curve; the air generator (5) directly affects operating temperature, oil life, the life of air generator (5) equipment, and parameters such as energy consumption. A decrease in this field increases system efficiency. The method offered by the invention enables the area below the curve to be reduced.

The invention is a control system offered with a microcontroller (13) based device (1 ) that can run advanced algorithms suitable for industrial use and is used in intermittent air-consumed systems. Device (1 ) contains hardware that controls all kinds of equipment in air consumption systems and contains software that offers a new method to run the air generator (5) very effectively.

An intermittent air consumed system which this device (1) will be used in consists of the following equipment.

- A device (1 ) with an algorithm to operate the compressed air generator (5) more effectively,

- An electric motor driver (2) driving the electric motor (3) of the compressed air generator (5),

- An electric motor (3) that rotates the compressed air generator (5),

- A direct coupled or belt-pulley type power transmission system (4) to transfer the rotation moment of the electric motor (3) shaft to the compressed air generator (5),

- A compressed air generator (5) to provide the air at the required pressure and flow rate,

- A relief valve (6) that will discharge the excess air in case of excessive pressure,

- An air tank (7) that stores some air and meets the air demands instantly,

- A pressure transmitter (8) that measures the pressure of the air in the air tank (7),

- A solenoid valve (9) that allows the passage of air in the air tank (7) to the system that will use the air,

- In the air consuming system; there is an air demand transmitter (10) that directly or indirectly determines the time to demand air and the amount of air needed.

On the device (1);

- A display screen (11 ) that gives information about the working status, - Input keys (12) for entering parameters,

- A microcontroller (13) to run advanced algorithms

- Analog signal inputs (14) to receive analog signals from the field and other devices,

- Digital signal inputs (15) to receive digital signals from the field and other devices,

- Analog signal outputs (16) for analog signals to be sent to field equipment,

- Digital signal outputs (17) for digital signals to be sent to field equipment,

- Relay contact outputs (18) for driving equipment in the field,

- Pulse outputs (19) to drive devices operating with square wave signal,

- Industrial communication modules (20) to connect to other devices via cable, using protocols such as 0-20mA, 4-20mA, 0-10V, i2C, RS232, RS485, Modbus, Profibus, ethernet,

- Pulse Width Modulation module (21 ) to output different current, voltage, frequency output and change these values,

- Stepper motor driver module (22) to run stepper motors,

- Wireless communication modules (23) which has protocols via wireless, bluetooth, etc.

- Power supply input (24) to feed the device itself and the sensors in the field,

- Programmable logic controller (PLC) modules (25) to communicate to the device (1) and control the industrial air consumption system,

- An electrical cabinet (26) to protect the device from external influences. Device (1 ) is manufactured using a microcontroller on a motherboard and electronic elements that will perform the functions listed above. The devices (1) to run in heavy industrial facilities may carried out using programmable logic controller (PLC) modules (25) that will function the same way instead of electronic elements.

The new method offered by the device (1 ) is described below and the operation of the device (1 ) consists of five main processes. These:

A. Parameter entry,

B. First run,

C. Reducing average pressure,

D. Reducing the average airflow,

E. System operation. In the first study, all processes are carried out respectively. Then the processes that the algorithm considers necessary are repeated and continued to be operated. The method of operation of each process and the work it does is stated below.

A. Entering parameters

When the device (1) is first energized, parameters are entered as follows and the device (1) is started.

- The "maximum set pressure" value that determines the pressure to be used in the consumption system is entered.

- In order to understand that sufficient air is supplied to the consumption system, the "minimum set pressure" value that determines the lowest value that the air pressure in the air tank (7) should decrease is entered.

- The “maximum set speed” value that determines the highest working speed of the compressed air generator (5) is entered.

- The "minimum set speed" value that determines the lowest operating speed that the compressed air generator (5) can operate is entered.

- The system is started by giving a run command to the device (1).

B. Startup

The device (1) recognizes the system by operating the system with standard values according to the parameters entered beforehand and operates as follows:

- The operating speed of the compressed air generator (5) is determined as the arithmetic average of the maximum set speed and minimum set speed values in the first operation.

- The device (1 ) activates the electric motor driver (2) at the determined operating speed. When the electric motor driver (2) is activated, the electric motor (3) starts to rotate and this rotational motion is transmitted to the compressed air generator (5) by the power transmission system (4). In this way, the compressed air generator (5) starts to rotate at the speed determined by the device (1 ). The rotation speed of the compressed air generator (5) determines the compressed air generation capacity. - The pressure of the air in the air tank (7) is monitored by the device (1 ) from the pressure transmitter (8) and expected to rise to the maximum set pressure.

- The time it takes to reach the maximum set pressure; It is recorded as "filling time" which determines how often air can be fed into the system.

- As soon as the maximum set pressure is reached, the solenoid valve (9) is operated and all the air in the air tank (7) is supplied to the system.

- The pressure of the air in the air tank (7) is monitored by the device (1 ) from the pressure transmitter (8) and is expected to decrease to the minimum set pressure.

- Time until it drops to the minimum set pressure; It is recorded as the "discharge time", which determines how long the air will be supplied to the system, that is, how long the solenoid valve (9) will remain active.

- As soon as the minimum set pressure is reached, the solenoid valve (9) is closed and the supply of air to the consumption system is stopped. The air pressure in the air tank (7) starts to rise again and the air tank (7) starts to fill again for the next use.

- The sum of filling time and discharge time values are recorded as consumption period.

- Using the data obtained by the device (1) at the initial operating speed, the capacity of the compressed air generator (5) at all operating speeds and the filling time of the air tank (7) are calculated.

- All measured and calculated parameters are stored in memory for processing and use.

C. Reduction of the mean pressure value

Reducing average air pressure is carried out in the following way:

- The aim of this algorithm is to reduce both operating temperature and energy consumption by reducing the average air pressure of the compressed air generator (5).

- Operating temperature of compressed air generator (5); depends on the average pressure the compressed air generator (5) is exposed to. The energy consumption of the compressed air generator (5) depends on both the average pressure the compressed air generator (5) is exposed to and the average airflow of the compressed air generator (5).

- To reduce the average air pressure value, parameters entered into the device (1) and data obtained during operation are used. - Average pressure value of compressed air generator (5); is the mean pressure of air in an air tank (7) during a consumption period. This value is calculated by the device (1) by taking integral the pressure values recorded during a consumption period and divide elapsed time.

- The device (1 ) is used to reduce the average pressure value, reduces the space under the "pressure-time curve" obtained from the pressure trace when accessing the maximum set pressure value from the minimum set pressure value by adjusting the speed of the compressed air generator (5).

- To do this, after the minimum set pressure value is reached, the speed of the compressed air generator (5) is reduced to the minimum set speed value. - In this calculation, it is aimed to spend most of the time at the lowest operating speed. The compressed air generator (5) starts to operate at the lowest speed when the air pressure is at the lowest value. If this speed is sufficient to increase the pressure to the maximum set value when air consumption demand comes, the speed is not increased. However, if it is not enough, the speed of the compressed air generator (5) is increased as the moment to be demanded approaches. When the moment when the air will be supplied to the system approaches, the speed of the compressed air generator (5) reaches its highest value.

- When the air pressure reaches the maximum set pressure at the end of the period, the solenoid valve (9) is immediately opened and all the air in the air tank (7) is supplied to the system and the pressure of the air tank (7) drops rapidly. When the pressure value reaches the minimum set pressure, the solenoid valve (9) closes, the speed of the compressed air generator (5) is reduced to the minimum set speed and the period starts again. - In order to increase the efficiency of the system, in each period, the air tank (7) is emptied completely at the moment it is full. The device (1) determines the moment when the air tank (7) is filled and completely emptied by reading the pressure value from the pressure transmitter (8). - While making calculations, mathematical formulations and optimization algorithms are used to reach the ideal solution.

- All measured and calculated parameters are stored in the database and saved to the database. These values are recalculated and updated with the information from the pressure transmitter (8) and the air demand transmitter (10) in each operating period.

- In the operation of the system; the differences between calculated values and actual values may be processed by an algorithm like deep learning, increasing the working efficiency.

- The decrease in the time when the compressed air generator (5) operates at high pressure reduces the level of noise caused by the air generator.

D. Reduction of the mean airflow value

The reduction of the average airflow is achieved by the following method:

- Energy consumption of the compressed air generator (5) depends on both the average pressure to which the compressed air generator (5) is exposed and the average airflow of the compressed air generator (5).

- The purpose of this part of the algorithm is to reduce energy consumption by reducing the average flow rate of the compressed air generator (5).

- The parameters entered into the device (1 ) and the data obtained during operation are used to reduce the mean airflow of the compressed air generator (5);

- The mean airflow is the average airflow of the air absorbed by the compressed air generator (5) during a consumption period. This value is calculated by the device (1) from simultaneously recorded both speeds of compressed air generator (5) and pressure values

- The method of decreasing the flow rate of the device (1 ) is to ensure that all the air produced by the compressed air generator (5) is used in the consumption system.

- As soon as the set pressure is reached, the solenoid valve (9) is immediately opened and all the air in the air tank (7) is immediately supplied to the consumption system. - The pressure value can never exceed the set pressure value. Thus, no air is discharged from the relief valve (6). All of the air produced is sent to the consumption system.

- Elimination of the air thrown out reduces the flow rate of the compressed air generator (5) by limiting the flow rate to the amount required by the system.

- Avoiding air outlets from the relief valve (6); reduces the level of noise caused by the system.

- While making calculations, mathematical formulations and optimization algorithms may be used to reach the ideal solution.

- In the operation of the system; the differences between calculated values and actual values may be processed by an algorithm like machine learning to increasing the accuracy of the operation.

E. Operation of the system

The following methods are used to update the system parameters and system:

- Device (1); It continuously analyzes the time to reach the maximum set pressure for each period. If this period is prolonged, it reports that there is a problem in obtaining the compressed air.

- Device (1); It continuously analyzes the time to fall to the minimum set pressure for each period. If this period is prolonged, it warns that sufficient air cannot be supplied to the consumption system.

- According to the information received from the air demand transmitter (10), if the consumption system requires more air, the consumption period value is shortened by the device (1 ). In this case, the compressed air generator (5) starts to work faster and gives more air to the system.

- According to the information received from the air demand transmitter (10), if the consumption system requires less air, the consumption period value is extended by the device (1). In this case, the compressed air generator (5) starts to run slower and gives less air to the system.

- During the working time of the device (1), the processes of mean pressure reduction, mean flow reduction and system operation are repeated continuously as a cycle.

- The device (1) works in coordination with the programmable logic controller (25) of the automation system in the facility and exchanges information about the facility status.

- If the device (1 ) receives a stop command, the compressed air generator (5) is stopped.

- If a run command is received on the device (1 ), all processes mentioned above are applied from the beginning.

Claims

1. A compressed air generator control system used in compressed air generators for intermittent air consumed systems characterized in that comprising;

- An electric motor driver (2) driving the electric motor (3),

- An electric motor (3) that rotates the compressed air generator (5),

- A direct coupled or belt - pulley type power transmission system (4) to transfer the rotational moment from rotor of the electric motor (3),

- A compressed air generator (5),

- A relief valve (6),

- An air tank that meets air demands instantaneously by storing some air (7)

- A pressure transmitter (8) that measures the pressure of the inside tank (7),

- A solenoid valve (9) that provides the pressurized air to be supplied to the system when needed,

- An air demand transmitter (10) that determines the air demand by directly or indirectly determining the time to demand air,

- Display (11),

- Input keys (12) for entering parameters,

- An electronic card with microcontroller (13) for simple air consumption systems, a programmable logic controller (PLC) module (25) consisting of input and output modules for heavy industrial applications to run advanced algorithms,

- Analog signal inputs (14) to receive signals from other equipment in the consumption system,

- Digital signal inputs (15),

- Solenoid valve (9), electric motors (3), electric motor driver (2), relays, analog signal outputs (16) to operate field devices in the system,

- Digital signal outputs (17),

- Relay contact outputs (18),

- Pulse outputs (19),

- Industrial communication modules (20) that are connected to other devices by cables to communicate with other devices, - Pulse width modulation module (21 ), which creates an analogue mean value using binary digital signals,

- Step motor driver module (22) to run step motors in air-consuming systems,

- Wireless communication modules (23), which provide wireless communication via wireless and bluetooth with other devices,

- Power supply inputs (24) for external feeding with various supply voltages,

- It is characterized by the device (1) and listed equipment to run the same operating algorithm for single or multiple air consumption systems, the number of equipment used may be less or more, the motor driver may not be used, or additional programmable logic controller (PLC) modules (25) may be used.

2. The microcontroller (13) of in Claim 1 characterized in that;

- Determining the operating speed of the compressed air generator (5) with the arithmetic mean of the maximum set speed and minimum set speed values at the first start,

- When the electric motor (3) starts rotating, the rotation movement is transferred by the power transmission (4) to the compressed air generator (5) and allows the compressed air generator (5) to start rotating at the speed determined by the device (1 ),

- Recording the time until the maximum set pressure is reached as the "Off- time", which determines how often air can be supplied to the system,

- As soon as the maximum set pressure is reached, it activates the solenoid valve (9) and ensures that all the air in the air tank (7) is given to the system,

- Keeping the solenoid valve (9) active until it drops to the minimum set pressure and records this time as "On-time",

- Stopping the supply of air to the consumption system by closing the solenoid valve (9) as soon as the minimum set pressure is reached,

- Recording the total of Off-time and On-time values as consumption period and calculates the capacity of the compressed air generator (5) at all operating speeds and the filling times of the air tank (7) by using the data obtained at the initial operating speed, - In order to reduce both operating temperature and energy consumption, reduces the mean pressure that compressed air generator (5) exposed by using parameters entered into the device (1) and data obtained during operation,

- During the consumption period, the air pressure values of the tank (7) are recorded, taking the integral of these values according to time and dividing them into the elapsed time, calculating the mean pressure value of the compressed air generator (5) exposed,

- Reducing the speed of the compressed air generator (5) to the minimum set speed value immediately after reaching the minimum set pressure value in order to reduce the mean pressure value,

- Calculating at what speed the compressed air generator (5) should operate during a period in order for the air pressure in the air tank (7) to reach the maximum pressure set value at the end of the air consumption period,

- When the air pressure in air tank (7) reaches the maximum set pressure at the end of the period, the solenoid valve (9) is immediately opened, which allows the air in tank (7) to be supplied to the system. Turns off the solenoid valve (9) when the pressure value reaches the minimum set pressure. It prevents the air pressure is higher than the pressure required by the system,

- Reducing the speed of the compressed air generator (5) back to the minimum set speed after the solenoid valve (9) is closed and allowing the operation to start again,

- Checking that the air tank (7) is filled and completely emptied by reading the pressure value from the pressure transmitter (8) in each period,

- Calculating the mean airflow from the speed of compressed air generator (5) by using recorded the pressure and speed values of simultaneously during the consumption period,

- Using the pressure signal or the information obtained by processing the pressure signal, as soon as the set pressure is reached, opens the solenoid valve (9) immediately, allows all air in the air tank (7) to be immediately flown into the system, produces only the required amount of air, prevents unnecessary air production, and thereby reduces the average air pressure and airflow of compressed air generator (5), and decreases energy consumption and working temperature.

- Recording all measured and calculated parameters in the database and enables them to be updated by recalculating with the information coming from the pressure transmitter (8) and the air demand transmitter (10) in each working period,

- Continuously analyzing the time to reach the maximum set pressure for each period and states that there is a problem in obtaining compressed air if this period is prolonged,

- Continuously analyzing the time to fall to the minimum set pressure for each period and warns that sufficient air is not given to the consumption system if this period is prolonged,

- According to the information received from the air demand transmitter (10), if the consumption system requires more air, it increases the speed of the compressed air generator (5) and reduces the consumption period value,

- According to the information received from the air demand transmitter (10), if the consumption system requires less air, reducing the speed of the compressed air generator (5) and extending the consumption period value,

- comprising a software that enables the continuous repetition of processes that reduce the average pressure and average airflow as long as the device (1) operates.