Electric Shading System for Greenhouse Cooling

Electric shading system for greenhouse cooling. During summer when temperatures are relatively high, greenhouses function as warm rooms. Without proper cooling equipment, the temperature difference between the inside and outside of the greenhouse can exceed 15 degrees Celsius, or even higher. This necessitates the greenhouse to seek an appropriate cooling method. The external shading system uses materials with a certain shading rate to block excess sunlight, or employs insulating materials to create a partially enclosed space inside the greenhouse, serving to regulate light, cool, or insulate. This external shading system adopts an A-type rack and pinion transmission, which offers the advantages of smooth operation and high transmission accuracy. The specific design plan is as follows:

1. System Principle

The A-type rack and pinion external shading system mainly consists of a reduction motor, drive shaft, rack and pinion assembly, support rollers, push-pull rods, curtain drive edge, curtain, and other components. Its transmission principle involves the drive shaft being connected to the reduction motor and the pinion gear. When the output shaft of the reduction motor rotates, the drive shaft drives the pinion gear to turn, and the rotation of the pinion gear drives the rack to move. The push-pull rods are supported by support rollers and connected to the rack. When the reduction motor rotates back and forth, it drives the push-pull rods to perform reciprocating motion. When one end of the shading curtain is fixed to a beam or column, and the other end is fixed to the drive edge profile connected to the push-pull rods, the unfolding and retracting actions of the shading curtain can be achieved.

2. System Basic Description

1. Reduction motor; 2. Coupling; 3. A-type pinion seat; 4. Rack; 5. Welded joint; 6. Curtain rack-push rod joint; 6a. Elastic cylindrical pin; 6b. Bolt; 7. A-type pinion seat gasket; 7a. Bolt; 8. Galvanized drive shaft; 9. Push rod; 10. Push rod-guide rod connection clip; 11. Support roller; 11a. Hex head self-drilling self-tapping screw; 11b. Bolt; 12. Drive edge aluminum profile; 13. Circlip; 14. External shading curtain

Transmission Mechanism:

Uses a rack and pinion transmission mechanism (A-type pinion), with power output through the drive shaft connected to the reduction motor. The drive shaft is made of φ42x2.5 steel pipe, connected to the motor in the middle, and evenly connected to the racks at other parts with a spacing of 3.2m. The transmission rod (φ25x2.0 hot-dip galvanized round pipe) and the push curtain rod are connected by fasteners, arranged horizontally to pull the curtain open and closed.

Technical Parameters:

External shading height: about 5.50m (determined on-site, with the external shading system about 500mm higher than the greenhouse ridge). Transmission type: Rack and pinion transmission mechanism, transmission along the bay direction.

Shading Net: The external shading curtain uses a domestic shading net with a shading rate of 75%. This shading net is designed to be more economical and practical based on the actual needs of domestic users. All raw materials are imported from abroad. In winter, the curtain can also reduce heat radiation from the greenhouse outward, protecting the greenhouse structure and plants from heavy rain, hail, and falling objects. This shading and insulating curtain remains clean and effective even after many years of use. The added UV stabilizers in the material resist common chemicals used in greenhouses, with an actual service life of over 10 years.

Curtain Lines: Both support and press lines are d2.2mm polyester lines with a tensile strength of 195kaf. The spacing between support lines is 0.4m, and between press lines is 0.8m. The support and press lines use black polyester lines with excellent anti-aging properties.

Control Zones: Divided into 1 zone for control.

3. System Installation

1) Layout and Fixing of Support (Press) Lines

Support (press) lines are fixed along the direction of curtain movement, evenly arranged along the curtain beam (external shading beam). Generally, support lines are placed every 400mm, and press lines every 800mm. Support (press) lines run from one curtain beam to the other along the direction of curtain movement, supported and fixed on the curtain beam (external shading beam) in the middle. 2) Drive Mechanism Installation

1 Installation of Curtain Support Rollers

Curtain support rollers are installed on the external shading beam of the greenhouse, fixed with bolts or ST5.5mmx25mm self-drilling self-tapping screws. The spacing is arranged with intermediate support rollers every 3.2m, and the two outer columns on both sides are about 300mm from the side gutters. 2 Layout and Installation of Reduction Motor

The reduction motor is fixed to the external shading column using a motor mounting bracket and U-bolts.

③ Installation of A-type Pinion Seat

The A-type pinion seat is installed on the external shading beam of the greenhouse with M8 bolts and pinion connection round washers. The drive shaft is segmented and connected to both ends of each pinion via welded joints, with the drive shaft welded to the welded joints. Steel clips are installed at both ends of each pinion shaft for easy maintenance. It is essential that the input shaft center of the A-type pinion seat, the output shaft center of the reduction motor, and the drive shaft center are aligned. ④ Installation of Rack and Push Rod

The rack and push rod are installed in a straight line, connected via a rack-push rod joint, elastic cylindrical pin, bolts, etc. ⑤ Installation of Moving Edge

The curtain is fixed into the aluminum alloy profile card slot with circlips, and the aluminum alloy drive edge is connected to the push rod with rod clamps and push rod-guide rod connection clips. The movement of the push rod drives the shading curtain to open and close.

3) Installation of Shading Curtain

Install the moving end of the shading curtain first, i.e., the end connected to the aluminum alloy drive edge, then install the fixed end of the shading curtain. 4) Connection to Power Distribution Control Box for Operation Debugging

After connecting the motor wires, carefully inspect the entire system before powering on to check for any oversights. Then start the motor switch to test whether the motor's forward and reverse rotation is correct.