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Optimum design of pneumatic roof bolter with vane motor
Published in Wang Yuehan, Ge Shirong, Guo Guangli, Mining Science and Technology, 2004
When it comes into operation, the compressed air enters the vane pneumatic motor via the operating valve of the operating mechanism to make it rotate. After reducing the speed by means of one stage planet it powers the roofbolting tip to drill the rock. At the same time, the compressed air enters the glass fibre reinforced plastic pneumatic leg by means of the operation valve group to drive the drilling rods and tips upward, and to realize the roofbolting hole formation. While drilling the rock and forming the hole, hydrostatic water is used to go through the centric hole of the drilling rod to enter the drilling tips for cooling and exterminating dust.
Pneumatics
Published in John S. Cundiff, Michael F. Kocher, Fluid Power Circuits and Controls, 2019
John S. Cundiff, Michael F. Kocher
Pneumatic motors convert compressed air to rotary motion. Typically, pneumatic motors are used in applications where the power requirement is less than 2.5 kW, though larger motors, up to 25 kW are available. They can be stalled without damage and remain in the stalled condition with very low power consumption. Because of their small rotating mass, they can be reversed very rapidly. No spark is generated by their operation, thus they are widely used for corrosive or explosive environments. Remember, the main disadvantage of a pneumatic motor is that speed always slows as torque increases. The two most common designs are piston and sliding vane.
Substrate pre-treatment by dry-ice blasting and cold spraying of titanium
Published in Surface Engineering, 2018
A cold spray system with a commercial cold spray gun (CGT GmbH, Ampfing, Germany) and an in-house nozzle was employed to prepare Ti coatings. During cold spraying, nitrogen with a pressure of 2.8 MPa was used as the accelerating gas and argon was used as powder carrier gas. The accelerating gas was operated at a pressure of 2.8 MPa and a temperature of 600°C. The gas was heated to 600°C. The standoff distance from the nozzle exit to the substrate surface was 30 mm. The mass rate of Ti powder was measured as 1.82 g s−1. The velocity of Ti particles arriving to the substrates was more than 500 m s−1, as referred in the literature [9]. A mobile blasting device (ic4000 system, HMRexpert, Etupes, France) was employed to carry out dry-ice blasting process, which comprises a similar-Laval nozzle with a rectangular outlet dimension of 9 × 40 mm, a mass flow controller with a pneumatic motor, a storage tank and a compressed air supplier. It is a compressed air-blasting process using solid carbon dioxide (i.e. dry ice) as a blasting medium. The solid carbon dioxides are drawn in by compressed air under negative pressure and then accelerated to the surface to be treated. This process is similar to the conventional sandblasting or grit-blasting. Cylindrical dry-ice pellets (−78.50°C) with a diameter of 3 mm and a length of 3–10 mm are used for blasting medium in this work; mass flow rate of dry-ice pellets was 42 kg h−1 under a gas pressure of 0.6–0.8 MPa. The velocities of the CO2 were estimated to be 78 m s−1 using finite element fluid simulation as reported in the previous work [10]. Before the coating deposition process, dry-ice blasting was employed to pre-treat the substrates and then was operated accompanying cold spraying. Both the cold spray gun and dry-ice blasting gun were installed on one robot arm and make a vertical and cyclical movement (Figure 2). All the substrates were pre-treated with two double-passes up and down by dry-ice blasting. Then, dry-ice blasting was accompanied with cold spraying which was opened subsequently to deposit coatings.