In view of the current low efficiency and difficulty of cleaning solar greenhouses in China, a semi-automatic solar greenhouse film cleaning machine was developed. The whole machine includes cleaning and walking parts. The cleaning part mainly includes DC motor, two sets of different reduction ratio reducers, cleaning brush and support rollers. The cleaning part is the core of the solar greenhouse cleaning machine. Under the forward rotation of the cleaning motor, the cleaning shaft is rotated at a high speed to drive the cleaning brush to complete the cleaning of the surface of the film. On the other hand, the climbing shaft is rotated by the speed reduction mechanism, thereby the entire cleaning section is climbed around the shaft by the pressing film ropes. The water spray pipe at the top of the cleaning part sprays water to the front of the cleaning brush, wets the film when it rises, and rinses the film when it is lowered, ensuring the cleaning effect and the cleanliness of the film after washing. The walking part mainly includes: a walking chassis, a motor drive axle, a support wheel, a guide wheel, an armrest, and a cleaning part placement platform. The walking chassis is equipped with a guide wheel to ensure that the walking part moves straight. The upper-end surface of the chassis is also equipped with a cleaning part placement platform, which adopts an eccentric structure design to ensure that the walking part is away from the film when the cleaning device is displaced; when the cleaning part enters the placement platform, the walking part fits the greenhouse keel to ensure smooth operation and improve work safety. From August 2018 to January 2019, the prototype was debugged and tested in the Science and Technology Innovation Park of Shandong Agricultural University. The solar greenhouse was a brick wall structure with a length of 40 m in East and west, a span of 10 m in North and south, and a ridge height of 5 m. Three greenhouses were used for different stages of experiments. The film cleaning performance test was carried out, and the influence of different cleaning parameters on the cleaning effect was analyzed. The results showed that the length of the cleaning brush can be set to 3 cm for the film used for three months; the reasonable speed range for the cleaning brush is 150-300 r/min. The cleaning requirement can be met for single-pass cleaning, the water pressure was 0.08 MPa, the flow rate was 3.5 L/min, and the double-pass cleaning the pressure was 0.05 MPa and the flow rate was 2 L/min. After using a new film for 3 months under natural conditions, the instantaneous transmittance of the film after cleaning was up to 90%, which was 15 percentage points higher than that without cleaning the film. The average light transmission period from 09:00 to 15:00 during the test period can be increased by 12 percentage points, and the stronger the outdoor light, the more obvious the transmittance is increased. The use of the device improves the cleaning efficiency of the solar greenhouse film and improves the illumination conditions in the shed and reducing the labor intensity. © 2019, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
