Design, development and performance evaluation of Pneumatic Type Semi-Automated Agarwood Inoculum Injector (PSAII)

Abstract

The “Agarwood” is a resinous bio-chemical fragrant produced by certain tree species of family Thymalaeaceae as a defense response to environmental stress. In commercial scale plantations, the causal stress is induced by artificial fungal inoculation. The effectiveness of the inoculation process is critically important to increase the productive harvest. The inoculum paste is made up with a high viscous agar medium to stick to the plant tissues inside drilled holes in the tree trunk and the branches. However, so far, no effective tool has been developed to deliver such a thick semisolid paste into the drill holes in Agarwood trees. At present, common silicon adhesive applicators (caulking guns) are used, which are inefficient, time-consuming, and ergonomically poor tools. To overcome these limitations, a Pneumatic type Semi-automated Agarwood Inoculum Injector (PSAII) was developed. A cast iron chamber of 6 L capacity was used as the pressure vessel. Standard HCFE 3/8″ non-return valve was fixed into the tank as an air inlet. The inoculum delivery out was sent through 1mm stainless steel strainer to avoid nozzle blocking. A pressure relief valve was incorporated to the pressure vessel and adjusted to 15 bars. The ambient air was used to compress the inoculum inside the tank once it is filled up to 5 L loading capacity. Comparison of performance between the new device with the existing caulking gun was done for the inoculum filling rate, labour efficiency and the inoculum wastage. With the new device, the average filling volume of inoculum inside the drill holes was increased up to 85.35% and reduced the inoculum wastage from 1.325mL to 0.47mL per drill hole and both improvements were significantly different at the 5% probability level (p<0.05). The results showed that the developed PSAII device is capable of delivering a smooth flow of inoculum paste to the target when the impending pressure thrust range within 5 to 15 bars. Moreover, within this pressure range, the total volume of 5L was delivered at a consistent rate. The new device PSAII was found to be highly successful in assisting the critical process of inoculation in the commercial level agarwood industry.