Automatic control of temperature, ventilation and lighting in the greenhouse in the 80s
Hi Habr!
I often read articles about various things collected by enthusiasts (and not only) that use high-tech devices based on modern microcontrollers, programmable, remote-controlled, capable of performing many different functions at the touch of a button, etc. Then one day, after reading another such article, I thought - how did people live without all this electronics before? After all, they controlled devices without it, analog circuits, relays, switches, etc. And then I remembered how my father, not being a radio electronics engineer, with the help of only analog devices available to him, made an almost completely autonomous climate control system in a greenhouse. Unfortunately, the father is already in old age and has practically lost his sight, so the article was written only from his words, does not contain concepts and any advanced descriptions, but I hope that everyone will understand what they mean.
Who cares - I ask under the cat.
')
It was in the already distant 80s. My parents were then actively engaged in growing flowers (tulips). During Soviet times, only the state was engaged in this. greenhouses and rare lovers. My parents put this case on stream - planting bulbs in the fall in greenhouses for “forcing” on March 8, harvesting, selling, and so on every year. Volumes were about 6-7 thousand bulbs in greenhouses. And since a tulip flower is quite delicate and from the slightest temperature fluctuations it can lose its presentation, then it was necessary to monitor the growth of flowers with increased attention. The problems were thrown up by the changeable weather of the southern coast of Crimea, where parents live. In winter, in February, the temperature during the day may rise to +18 and the sun shine with might and main, while at night it may fall to minus and “freeze” the top layer of soil. Constant fogs from the sea on sunny days brought high humidity and condensation from which the flowers became speckled and completely lost their presentation in one day. In such conditions, maintaining a constant temperature of +18 degrees, humidity and lighting in the greenhouse became completely hellish and tedious business. Parents were on duty, it can be said in shifts, constantly controlling the temperature, opening and closing the frames on the greenhouse roof, airing it, adjusting the heating temperature, and monitoring the humidity. And since dad went to work full-time, and mom was nursing with me little, there were times when everyone had strength and nerves to the limit and something needed to be solved - either to wrap up growing flowers or to leave my father , orsomewhere to put me :) automate the process. What in the end was done. I must say that my father was not a radio electronic engineer, he worked in the organization of Krymlift, which installed and repaired elevators, and in those years elevators worked on ordinary relays (yes, these are the elevators that still stand in high-rise buildings and click relyushkami on the technical floor). No electronics there and close smelled.
It was the easiest task to solve.
Due to the fact that winter is a short day, flowers need extra. light, so that they grow faster and are not pale. For this purpose, several different types of lamps were used - ordinary Ilyich lamps of 150-200 W each, infrared lamps and fluorescent lamps. All this was hung up at a certain height, turned on early in the morning and turned off in the evening. For switching on and off monitored time relay type RVM2
You can read more here.
Simple as a door, but at the same time it allowed to “program” the time of switching on and off two (and in some versions more) contacts. It works like this: on the disc there are 2 tracks of holes in which the pins are screwed. Each hole corresponds to a timestamp at intervals, for example, every 15 minutes. The disk rotates slowly by the electric motor. At some point, the pin reaches the contact and starts to turn it, turning the contact 90 degrees either closes or opens. Screwing the pins into the necessary holes, we get a timer of its own, which copes with the task. And since contacts 2 then IR lamps turn on and off several times a day, when the general lighting is on for about 12 hours a day.
Drain the greenhouse and remove condensate from all internal surfaces during high humidity from the outside. At first, the task seemed not easy. Moreover, the soil should be sufficiently moistened. The moisture evaporates from its surface and very intensively from the flowers at the same time condensing intensely on the film that covers the greenhouse. The solution turned out to be quite simple and effective - what is now called heat guns (big hairdryer). In the pipe of large diameter a fan was inserted which drove the air through the heated spirals. The air dried out and the condensate settled less. But the problem was different - such guns needed to be turned on somehow, depending on humidity and temperature, since they not only dried the air, but also heated it. Another analog device came to the rescue - a humidity sensor (photo unfortunately could not be found). This sensor was a box through which the air flow passed and, depending on its humidity, miraculously closed the contacts. This sensor could be adjusted to the required humidity and at the same time it worked with a permissible error. The sensor closed the magnetic starter, which in turn already included the guns. For greater accuracy, the sensor was placed in the zone of action of one of the guns so that dry air was blowing on it, while the system was often turned on for short periods of time without overheating the air. Due to the large inertia of the room, the humidity was maintained fairly evenly. Condensate did not accumulate in large volumes and there was no precipitation in the greenhouse :) Profit!
More difficult than the above was to ensure a stable temperature inside. And there were 2 ways of development: simple - to make electric heating (air heaters) and a temperature sensor. And the way my dad went is to upgrade water heating by running a liquid fuel boiler depending on the temperature. Soviet people are not looking for easy ways :)
But the first option had only one plus - simplicity of installation and configuration, there were more minuses - it dries the air, it was not safe (the heating elements needed to be hung all over the greenhouse), expensive (to find and buy was not so easy in a small town). Water heating has already been done, plus it was also laid under the beds to warm the ground to achieve faster shoots of the bulbs, and it would be unrewarding to bury them under the ground, plus the load on the meter would have led to its obvious loss. Resolved - modernize the old system! To do this, you must have a temperature sensor inside the greenhouse, somehow regulate the flow of fuel to the burner, and ensure emergency shutdown. Now it would all be decided by ordering the necessary parts on the Internet or by going to the nearest radio store with subsequent installation and fine-tuning, a week at most. Then it took about 2 years ... To adjust the flow of diesel oil (yes, it was she who was then heated for 70 rubles per 1000 liters :)) a lot of things were tried, but the most optimal at that time was a system of 4 electro valves that were connected in parallel and opened opened depending on the air temperature thereby increasing the flow of fuel to the burner. Four thermometers served as sensors:
each connected to its own valve. Read more here . This thermometer was really cool, at least then it seemed to me so. Probably because there were wiring in it, silver mercury (a lot), contacts, 2 scales and so on. The principle of its operation is this - near the bubble with mercury the wiring was soldered, which applied voltage to the mercury itself. On the other side of the tube where this mercury moved, a thin wiring was placed, which set the temperature. It could be moved using a twister at the top of the thermometer, which rotated the threaded rod and nut to which this posting was attached. Probably he wrote a lot of confusion, but there are more details on the link, I hope his principle will be clear.
In general, when the mercury rose to the desired temperature, it closed the conductors through itself (touching the wiring in the tube) and so the low-power relay worked, which in turn closed the valve and "turned off the heat." As soon as the temperature fell, the circuit opened, the valve opened and more fuel entered the boiler. The temperature was rising. You ask - why four such systems - for smooth adjustment. Thermometers were set at intervals of 2 degrees. Those. a temperature range of almost 10 degrees was provided, which was quite enough for smoothing daytime temperature fluctuations. At night, all the valves, usually depending on the temperature, were open and the boiler was burning at full capacity. Such a seemingly simple system posed one problem — because of the inertia of the coolant and its slow circulation inside the heating circuit, the air overheated, which almost caused damage to the entire “harvest” once. A circulation pump did not make the situation much better. 500+ liters of water in the system will not cool quickly. Yes, and with the sudden illumination of the greenhouse by the sun, the temperature inside could rise in a matter of minutes above normal. And after much suffering, it was decided to make a ventilation system. But she was not trivial either.
The simplest thing is to insert the fan into the wall of the greenhouse. But this father did not even to automate the process. The reason is simple - when it is not used - the hole must be closed so that the warm air does not go out. Also the fan is not very useful that blows. Hm but what else can he do? This is his and minus - condensate on the flowers and they, you understand - not a presentation and the whole lid. So that this was not in the greenhouses, the opening upper frames were made, roughly speaking - the roof was rising! It was the craziest thing you could do! But it was so effective that it raised the quality of the crop to almost 100%!
The system was made on the basis of the drive to open the elevator doors. The photo was not found, but the principle is this - the unit consisted of the engine itself, the gearbox and the lever mechanism. He worked on the principle of wipers in the car - the motor rotates and through the gearbox turns the lever then one way or the other. Further, this whole system was adapted inside the greenhouse under the movable roof frame. The frame itself was fixed by one edge in the center of the roof (on the ridge) and the other edge was lying loosely on the wall of the greenhouse. He was raised by a lever from below. The power was quite enough to raise the frame to a height of 40 cm. But the method of scientific pumping raised the lift to 10 cm. With this lift, good ventilation was provided, not a sharp drop in temperature and a smooth flow of fresh air over a large area. It all worked quite simply - another control thermometer, which was set at 20 degrees (critical temperature). When the circuit was closed, the frame rose and the air cooled, the thermometer opened the circuit and the frame lowered. The whole cycle of opening / closing the frame took no more than 10 minutes, then the air slowly heated up again and if the critical temperature set in, the airing worked.
After airing, the guns usually worked to dry out fresh air, which was sometimes more humid.
At first glance, the system may seem unnecessarily difficult for such a seemingly trivial task, but it has really proven itself. For all the artisanal assembly of critical failures did not happen. The maximum were poorly connected contacts that did not lead to anything serious. During the operation of the system, the yield was at the highest level with minimal interventions in the process.
The whole thing lasted until the beginning of the 90s and became unprofitable when they began to carry flowers from Holland. It became difficult to compete with outbidings on the spot, if the father used to load boxes with flowers, loaded onto a plane and flew the day to sell flowers somewhere beyond the horizon of our vast country then, after the collapse of the union, this was no longer real. Yes, and the age of the parents was not the same.
But the design just did not go down in history. According to his father, an amateur gardener came to him from somewhere in the center of Ukraine, where he was also engaged (and probably is still engaged) in growing flowers and writing down, drawing, remembering how everything works. After that, did something similar in his. And already according to his modernized system there was an article in some magazine, then “Ogorodnik”, or “Household Floriculture”, then in some similar one. If someone knows something about what kind of magazine it was, I will be grateful to you.
Thanks for attention!
I often read articles about various things collected by enthusiasts (and not only) that use high-tech devices based on modern microcontrollers, programmable, remote-controlled, capable of performing many different functions at the touch of a button, etc. Then one day, after reading another such article, I thought - how did people live without all this electronics before? After all, they controlled devices without it, analog circuits, relays, switches, etc. And then I remembered how my father, not being a radio electronics engineer, with the help of only analog devices available to him, made an almost completely autonomous climate control system in a greenhouse. Unfortunately, the father is already in old age and has practically lost his sight, so the article was written only from his words, does not contain concepts and any advanced descriptions, but I hope that everyone will understand what they mean.
Who cares - I ask under the cat.
')
A bit of history
It was in the already distant 80s. My parents were then actively engaged in growing flowers (tulips). During Soviet times, only the state was engaged in this. greenhouses and rare lovers. My parents put this case on stream - planting bulbs in the fall in greenhouses for “forcing” on March 8, harvesting, selling, and so on every year. Volumes were about 6-7 thousand bulbs in greenhouses. And since a tulip flower is quite delicate and from the slightest temperature fluctuations it can lose its presentation, then it was necessary to monitor the growth of flowers with increased attention. The problems were thrown up by the changeable weather of the southern coast of Crimea, where parents live. In winter, in February, the temperature during the day may rise to +18 and the sun shine with might and main, while at night it may fall to minus and “freeze” the top layer of soil. Constant fogs from the sea on sunny days brought high humidity and condensation from which the flowers became speckled and completely lost their presentation in one day. In such conditions, maintaining a constant temperature of +18 degrees, humidity and lighting in the greenhouse became completely hellish and tedious business. Parents were on duty, it can be said in shifts, constantly controlling the temperature, opening and closing the frames on the greenhouse roof, airing it, adjusting the heating temperature, and monitoring the humidity. And since dad went to work full-time, and mom was nursing with me little, there were times when everyone had strength and nerves to the limit and something needed to be solved - either to wrap up growing flowers or to leave my father , or
Additional lighting
It was the easiest task to solve.
Due to the fact that winter is a short day, flowers need extra. light, so that they grow faster and are not pale. For this purpose, several different types of lamps were used - ordinary Ilyich lamps of 150-200 W each, infrared lamps and fluorescent lamps. All this was hung up at a certain height, turned on early in the morning and turned off in the evening. For switching on and off monitored time relay type RVM2
You can read more here.
Simple as a door, but at the same time it allowed to “program” the time of switching on and off two (and in some versions more) contacts. It works like this: on the disc there are 2 tracks of holes in which the pins are screwed. Each hole corresponds to a timestamp at intervals, for example, every 15 minutes. The disk rotates slowly by the electric motor. At some point, the pin reaches the contact and starts to turn it, turning the contact 90 degrees either closes or opens. Screwing the pins into the necessary holes, we get a timer of its own, which copes with the task. And since contacts 2 then IR lamps turn on and off several times a day, when the general lighting is on for about 12 hours a day.
Humidity
Drain the greenhouse and remove condensate from all internal surfaces during high humidity from the outside. At first, the task seemed not easy. Moreover, the soil should be sufficiently moistened. The moisture evaporates from its surface and very intensively from the flowers at the same time condensing intensely on the film that covers the greenhouse. The solution turned out to be quite simple and effective - what is now called heat guns (big hairdryer). In the pipe of large diameter a fan was inserted which drove the air through the heated spirals. The air dried out and the condensate settled less. But the problem was different - such guns needed to be turned on somehow, depending on humidity and temperature, since they not only dried the air, but also heated it. Another analog device came to the rescue - a humidity sensor (photo unfortunately could not be found). This sensor was a box through which the air flow passed and, depending on its humidity, miraculously closed the contacts. This sensor could be adjusted to the required humidity and at the same time it worked with a permissible error. The sensor closed the magnetic starter, which in turn already included the guns. For greater accuracy, the sensor was placed in the zone of action of one of the guns so that dry air was blowing on it, while the system was often turned on for short periods of time without overheating the air. Due to the large inertia of the room, the humidity was maintained fairly evenly. Condensate did not accumulate in large volumes and there was no precipitation in the greenhouse :) Profit!
Heating
More difficult than the above was to ensure a stable temperature inside. And there were 2 ways of development: simple - to make electric heating (air heaters) and a temperature sensor. And the way my dad went is to upgrade water heating by running a liquid fuel boiler depending on the temperature. Soviet people are not looking for easy ways :)
But the first option had only one plus - simplicity of installation and configuration, there were more minuses - it dries the air, it was not safe (the heating elements needed to be hung all over the greenhouse), expensive (to find and buy was not so easy in a small town). Water heating has already been done, plus it was also laid under the beds to warm the ground to achieve faster shoots of the bulbs, and it would be unrewarding to bury them under the ground, plus the load on the meter would have led to its obvious loss. Resolved - modernize the old system! To do this, you must have a temperature sensor inside the greenhouse, somehow regulate the flow of fuel to the burner, and ensure emergency shutdown. Now it would all be decided by ordering the necessary parts on the Internet or by going to the nearest radio store with subsequent installation and fine-tuning, a week at most. Then it took about 2 years ... To adjust the flow of diesel oil (yes, it was she who was then heated for 70 rubles per 1000 liters :)) a lot of things were tried, but the most optimal at that time was a system of 4 electro valves that were connected in parallel and opened opened depending on the air temperature thereby increasing the flow of fuel to the burner. Four thermometers served as sensors:
each connected to its own valve. Read more here . This thermometer was really cool, at least then it seemed to me so. Probably because there were wiring in it, silver mercury (a lot), contacts, 2 scales and so on. The principle of its operation is this - near the bubble with mercury the wiring was soldered, which applied voltage to the mercury itself. On the other side of the tube where this mercury moved, a thin wiring was placed, which set the temperature. It could be moved using a twister at the top of the thermometer, which rotated the threaded rod and nut to which this posting was attached. Probably he wrote a lot of confusion, but there are more details on the link, I hope his principle will be clear.
In general, when the mercury rose to the desired temperature, it closed the conductors through itself (touching the wiring in the tube) and so the low-power relay worked, which in turn closed the valve and "turned off the heat." As soon as the temperature fell, the circuit opened, the valve opened and more fuel entered the boiler. The temperature was rising. You ask - why four such systems - for smooth adjustment. Thermometers were set at intervals of 2 degrees. Those. a temperature range of almost 10 degrees was provided, which was quite enough for smoothing daytime temperature fluctuations. At night, all the valves, usually depending on the temperature, were open and the boiler was burning at full capacity. Such a seemingly simple system posed one problem — because of the inertia of the coolant and its slow circulation inside the heating circuit, the air overheated, which almost caused damage to the entire “harvest” once. A circulation pump did not make the situation much better. 500+ liters of water in the system will not cool quickly. Yes, and with the sudden illumination of the greenhouse by the sun, the temperature inside could rise in a matter of minutes above normal. And after much suffering, it was decided to make a ventilation system. But she was not trivial either.
Ventilation system
The simplest thing is to insert the fan into the wall of the greenhouse. But this father did not even to automate the process. The reason is simple - when it is not used - the hole must be closed so that the warm air does not go out. Also the fan is not very useful that blows. Hm but what else can he do? This is his and minus - condensate on the flowers and they, you understand - not a presentation and the whole lid. So that this was not in the greenhouses, the opening upper frames were made, roughly speaking - the roof was rising! It was the craziest thing you could do! But it was so effective that it raised the quality of the crop to almost 100%!
The system was made on the basis of the drive to open the elevator doors. The photo was not found, but the principle is this - the unit consisted of the engine itself, the gearbox and the lever mechanism. He worked on the principle of wipers in the car - the motor rotates and through the gearbox turns the lever then one way or the other. Further, this whole system was adapted inside the greenhouse under the movable roof frame. The frame itself was fixed by one edge in the center of the roof (on the ridge) and the other edge was lying loosely on the wall of the greenhouse. He was raised by a lever from below. The power was quite enough to raise the frame to a height of 40 cm. But the method of scientific pumping raised the lift to 10 cm. With this lift, good ventilation was provided, not a sharp drop in temperature and a smooth flow of fresh air over a large area. It all worked quite simply - another control thermometer, which was set at 20 degrees (critical temperature). When the circuit was closed, the frame rose and the air cooled, the thermometer opened the circuit and the frame lowered. The whole cycle of opening / closing the frame took no more than 10 minutes, then the air slowly heated up again and if the critical temperature set in, the airing worked.
After airing, the guns usually worked to dry out fresh air, which was sometimes more humid.
At first glance, the system may seem unnecessarily difficult for such a seemingly trivial task, but it has really proven itself. For all the artisanal assembly of critical failures did not happen. The maximum were poorly connected contacts that did not lead to anything serious. During the operation of the system, the yield was at the highest level with minimal interventions in the process.
The whole thing lasted until the beginning of the 90s and became unprofitable when they began to carry flowers from Holland. It became difficult to compete with outbidings on the spot, if the father used to load boxes with flowers, loaded onto a plane and flew the day to sell flowers somewhere beyond the horizon of our vast country then, after the collapse of the union, this was no longer real. Yes, and the age of the parents was not the same.
But the design just did not go down in history. According to his father, an amateur gardener came to him from somewhere in the center of Ukraine, where he was also engaged (and probably is still engaged) in growing flowers and writing down, drawing, remembering how everything works. After that, did something similar in his. And already according to his modernized system there was an article in some magazine, then “Ogorodnik”, or “Household Floriculture”, then in some similar one. If someone knows something about what kind of magazine it was, I will be grateful to you.
Thanks for attention!
Source: https://habr.com/ru/post/199366/
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