Do-it-yourself thermal actuator for greenhouses: how to make it right

The advantages of using

Any gardener knows that greenhouses need to be ventilated regularly. This normalizes the temperature and humidity in the greenhouse. In the case of using automatic ventilation of greenhouses, there is no need for constant human control – the drive independently opens the frames and doors for ventilation at elevated temperatures, and accordingly closes when it drops. This mechanism will be simply indispensable for amateur gardeners who visit their dachas only on weekends or simply want to have more free time.

There are a variety of types of systems that allow you to arrange effective purge of greenhouses (from primitive to complex):

1. Automated opening of vents in the side of the greenhouse or its roof. This option is perfect for small greenhouses. When placing ventilation holes (windows), it is important to consider that there must be at least two of them. And they should be placed at different heights: one is higher and the other is lower.
2. For greenhouses of more impressive sizes, it is worth providing for more intensive ventilation, therefore, for such buildings, a scheme is used according to which two vents are located side by side or use doors.
3. Through purge greenhouse. To do this, use the ends of the building – their simultaneous opening. This version of the ventilation system is perfect for long, narrow greenhouses.
4. Ventilation system using sophisticated technology – sensors that respond to humidity levels and temperature. Such systems are quite expensive, therefore they are rarely installed in summer cottages and adjacent territories of amateur gardeners, but many craftsmen develop their own thermal actuators with their own hands.

Which system is the best – everyone must decide for himself, given the characteristics of the greenhouse, but remember that automatic ventilation of greenhouses will significantly increase yields and facilitate plant care.

How the device works

Recently, many diverse thermal actuators for greenhouses of various configurations have appeared on sale, which effectively provide ventilation for greenhouses. The simplest greenhouse ventilation machine is based on a hydraulic device. Inside, this device is filled with a liquid that reacts to changes in ambient temperature: an increase in temperature contributes to the expansion of the substance, which pushes the piston and the ventilation hatch opens. Accordingly, with a decrease in temperature, the liquid narrows – the window closes. Often, a thermal drive is made of stainless metal so that it lasts for a long time, but if the greenhouse is seasonal, the mechanism should be stored in a dry place for the winter.

Is it possible to make your own

Many gardeners make a device for ventilating greenhouses with their own hands. To do this, automobile hydraulic cylinders, gas shock absorbers, cylinders from computer chairs, etc. are used. The main thing is to use a substance that will expand and contract well depending on temperature indicators. Let’s consider how to create an automatic machine for airing a greenhouse from a cylinder from a computer chair. This method has already been tested by many gardeners. For the design, you need a cylinder from a computer chair with a steel stem on one side and a plastic stem from the valve on the other.

Sequence of work:

1. Secure the plastic rod in a vise and pull it out with a sharp movement. Inside is a metal valve pin.
2. Fix in a vise a rod with a diameter of 8 mm, the length of the working part is 6 cm. Insert a cylinder onto this rod – when pressed, the pressure will go away.
3. Cut off the taper cylinder.
4. Carefully press the steel rod out of the cylinder so as not to damage it and the cuff on the cylinder.
5. Using two layers of canvas mitt, clamp the rod in a vise and cut the M8 thread. Remove cuffs.
6. Replace the sleeve that is located inside the cylinder. Take the aluminum piston (the rest of the parts are not needed) and release it from the rubber rings.
7. Clean parts from metal shavings. Gasoline is fine for this.
8. Insert the rod into the inner sleeve and remove it from the cylinder. Do everything carefully so as not to damage the seal.
9. Screw the M8 nut onto the thread.
10. Insert aluminum piston.
11. Take a pipe with threads on one side and weld it to the cut side of the cylinder.
12. Thread an M8 long nut onto the stem threads.
13. Screw in the plug to connect to the window.
14. Pour engine oil into the structure and completely bleed the air.

Video “The principle of operation of the thermal drive”

This video shows you how a thermal drive works.

Installation of the thermal actuator

The greenhouse ventilator is mounted on a ventilation frame. Also, the thermal actuator can be installed on the greenhouse door. Here everyone makes their own decision, taking into account the needs. 

Pay attention to some important points that you should definitely take into account when installing a greenhouse ventilation device: the total area of ​​​​ventilation hatches should not occupy more than a quarter of the entire greenhouse area; frames should be evenly spaced over the entire area. Automatic ventilation of greenhouses is a unique system that greatly simplifies the maintenance of a do-it-yourself greenhouse and the process of growing various crops in it as a whole. The installation of a thermal actuator provides optimal temperature conditions in the greenhouse without any human intervention.

Video “Overview of the thermal actuator”

Video-overview of thermal power plants.