De-dusting System and Principle of DTH Drilling Rigs

Oct. 13, 2023

During the operation of a DTH drilling rig, not only is the dust concentration at the workplace high but also the dust particles are widely distributed. During the drilling operation, the rock dust is blown from the bottom of the hole to the ground by the compressed air, and if no measures are taken, it will spread in the atmosphere and form environmental pollution. In other words, the dust removal effect of the drilling rig is an important performance indicator to evaluate the drilling rig.

DTH drilling rig


De-dusting method

There are two types of de-dusting methods: one is wet de-dusting and the other is dry de-dusting. The two types of dust removal methods have different effects on different rock properties and hydrogeological conditions. Dry de-dusting uses cyclone separation and filtration, while wet de-dusting uses water spraying in the compressed air to moisten the rock powder so that it does not drift away. Dry-type dust removal requires regular replacement of filter cartridges, and the cost of filter cartridges is high. If the perforated geology contains high water, the filter element is easy to clog. Wet dust removal water added to compressed air, through the drill pipe, impactor deep into the bottom of the hole, increasing the amount of water used in production operations, is not conducive to the drill and impactor.


The dry dust removal system

The dry de-dusting system of the drilling rig mainly consists of filters and air ducts. In the process of drilling tool gouging, rock dust is blown out of the hole through the annular space between the drill pipe and the gun hole wall under the joint action of compressed air and dust collector fan suction. The dust catcher encloses the dust and prevents it from blowing out from the drill pipe and the surrounding space. The airflow with dust enters the primary filter at high speed through the dust catcher and dust suction pipe. The flow of dust enters the primary filter at high speed through the dust trap and the suction pipe. Once the rock slag is in contact with the wall, it loses its radial inertia force. Under the action of centrifugal force, the rock slag is separated from the airflow and falls down, and is discharged from the filter, completing the first stage of dust removal in the dust removal system. The airflow containing rock powder enters the secondary filter and is filtered and purified by the filter element of the pulse dust collector and then adheres to the filter element. The rock is discharged from the pulse dust collector under the high-pressure spray of the electromagnetic pulse valve, completing the secondary dust removal of the dust removal system.


Wet de-dusting system

Wet de-dusting is done by mixing the pressurized air with water through a mixer and pumping the water from the tank to the water pipe. The compressed air supplied by the air compressor will be dispersed into a very fine water mist, and the air-water mixture will enter the bottom of the hole through the air-water joint and the drill pipe. The wind flow from the hole fan will blow the discharged mud to the side of the hole and deposit it there. After drying, it is colloidal and no secondary fluttering occurs. The wet dust removal of the drilling rig has a good effect on suppressing the dust flying and improving the working environment of the workers on site.


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