The core components of soil gas sampling threaded drills usually include threaded drill bits, drill rods (including extension rods), handheld/driving parts, and some with gas collection functions are also equipped with sampling tubes, seals, etc. The assembly needs to follow the logic of "checking and adapting - sequentially connecting - reinforcing seals - functional verification" to ensure that there is no gas leakage and stable drilling in subsequent sampling. The specific steps are as follows:
Preparation before assembly
Component inspection: First, check the integrity of each component, including threaded drill bits, extension rods, T-shaped handles (or other handheld components), sampling tubes (specifically designed for gas sampling), matching wrenches, etc. At the same time, check the status of the components to ensure that the drill bit threads are not deformed, the drill rod is not bent or cracked, the sampling tube is not damaged, the sealing components (such as sealing rings) are not aged, and all threaded interfaces are not corroded to avoid affecting assembly and sampling accuracy due to component damage. In addition, it is necessary to confirm that all component connection types are consistent to prevent interface incompatibility.
Cleaning treatment: Use a clean cloth to wipe off dirt, oil stains, and other impurities on the surface of each component, especially the threaded interface and sampling channel, to avoid impurities getting stuck in the threads and causing loose connections or blocking the gas sampling channel, which may affect gas sample collection.
Core component assembly
Connect the handheld component to the drill rod: First, connect the T-shaped handle to the base drill rod, align the threaded interface of both, and manually rotate clockwise to preliminarily fix it. Afterwards, use the matching wrench to further tighten to ensure a secure connection and prevent the handle from loosening and slipping during drilling. If the sampling depth is deep, an extension rod needs to be installed, using the same threaded docking method. The extension rod should be connected section by section, and each section should be reinforced with a wrench, ensuring that each section of the drill rod is coaxial to prevent uneven stress during drilling.
Install threaded drill bit: Select the appropriate threaded drill bit based on the soil type (such as spiral dense drill bit for cohesive soil), align the threaded end of the drill bit with the threaded interface at the bottom of the drill rod, and manually screw it in clockwise. After turning to the point where it cannot be rotated, use a wrench to assist in tightening, paying attention to moderate force to avoid damaging the drill thread with excessive force. For drill bits with gas injection holes, it is necessary to ensure that the injection hole of the drill bit is aligned with the gas path channel inside the drill rod, which is the key to ensuring smooth gas collection.
Assembly of gas sampling exclusive components
Installation of sampling tube and valve: If the drill rod is equipped with a sampling tube interface, connect one end of the sampling tube to the corresponding interface of the drill rod through a thread or quick connector, and wrap sealing tape around the connection to enhance sealing. Next, install a manual valve on the sampling tube and close the valve to prevent soil from entering the sampling tube and contaminating the gas path during drilling.
Assembly auxiliary seals: For sampling scenarios that require isolation from external air, install sealing rings or gaskets at the connection between the drill rod and the drill bit, as well as at the interface of the sampling tube. Check that the seals are tightly fitted to avoid external air infiltration during sampling, which may cause distortion of the gas sample data. Partial integrated equipment also requires the installation of anti mud components, such as anti mud covers, fixed on the upper end face of the drilling end to prevent soil from blocking the sample hole.
Verification after assembly
Stability test: After assembly, gently shake the overall equipment to check that there is no looseness or shaking at each connection, and that the drill bit and drill rod are not offset.
Gas path sealing test: If it is specifically for gas sampling, briefly open the valve of the sampling tube, gently cover the end of the sampling tube with your hand, feel if there is any abnormal gas flow, or simply connect the sampling bag, lightly press the drill rod, observe if there is gas entering the sampling bag and no leakage, confirm that the gas path is well sealed, and then close the valve to prepare for sampling.