Belt connection

Reciprocating compressors are available with a large variety of other drivers, which include the piston engine, steam turbine, or, in rare cases, a gas turbine. Next in popularity to the electric motor is the piston engine. The arrangement lends itself to skid mounting, particularly with the semi-portable units found in the oilfield. The unit is also popular as a lease unit, which may be lifted onto a flat bed trailer and moved from one location to another as needed. The engine is either direct-coupled or. as with smaller compressors, it may be belt-connected. 

This type of blade is well suited to streamline flow conditions and is used extensively on ventilating, air conditioning, and clean and dirty process gas streams. The backward blade does not catch dirt easily. The outstanding and important characteristic is the nonoverloading horsepower. This is the only commonly used blade style with this feature. It is important in process control and eliminates the need for oversized motors or other drivers. Speed of operation is high, which allows direct or belt connection to the driver. Certain streamlined blade designs provide the same basic characteristics with more efficient and quieter operation. The usual... 

Fig. 3 shows the experimental apparatus. The feed tank had a 50 gallon capacity and was equipped with a variable speed mixer. The feed pump was a flexible impeller, positive-displacement pump to minimize shearing of the feed emulsion. The pumping rate was regulated by a Graham Variable Speed Transmission. Each flotation tank was 11.5 in. ID with 6.5 in. liquid depth maintained by a CE IN-VAL-CO conductometric level controller with a pneumatically actuated control valve in the effluent line. The fourth cell was not equipped with an air inducer. The outer diameter of the air downcomers was 1.5 in. The rotor in each air inducer was a turbine taken from a 2 in. turbine flow meter. Each rotor was belt driven by a 10,000 rpm, 1/30 hp motor and all three motors were governed by the same variable transformer. Another pulley on each rotor shaft was attached to a non-powered belt connecting all three shafts to ensure that each rotor turned at the same speed. 

The INET contactors have also been applied to non-nuclear processes, such as the removal of a specific rare metal (yttrium) from other rare metals (Zhou et al., 2007), hydrocortisone from fermentation liquor (Zhou et al., 2006b), phenol from wastewater (Xu et al., 2006), and caffeine from coffee beans (Duan et al., 2006). As described by Zhou et al. (2007), the contactor rotor is driven by a motor that is not above the contactor. Instead, a belt connects the motor to the top of the rotor shaft. This design is possible because these materials are not radioactive, and hands-on maintenance is thus possible. 

FIGURE 12.5. Underground conveyer belt connection to the ore dressing plant. By courtesy of Wolfram Beigbau und Hiittenges. m.b.H., Austria. 

A fall arrest system is employed when a worker is at risk of falling from an elevated position. A positioning system restrains the elevated worker, preventing them from getting into a hazardous position where a fall could occur, and also allows hands-free work. Both systems have three components harnesses or belts, connection devices, and tie-off points. 

Power transmission apparatus functions as the part of the mechanical system that transmits energy to the part of the machine performing the work. These components include flywheels, pulleys, belts, connecting rods, couplings, cams, spindles, chains, cranks, and gears. 

The standard requires that employees working from an aerial lift be protected by either a fall restraint system or a personal fall arrest system. A body belt connected to a lanyard cannot be used. A lanyard connected to a harness as part of a personal fall arrest system can be used, however. 

Example Manual tasks in the derrick are a concern, especially those carried out outside work platforms. Here a riding belt connected to a special... 

The basket is mounted on a drive shaft, which may be directly coupled to the drive motor, or the motor may sit to one side of the centrifuge, with a pulley and belt connection to the drive shaft. The axis of the basket may be vertical, with the open end at the top (the reverse orientation, with open end at the bottom is perfectly feasible, but rarely seen), and with suspension feed through the open end. Cake removal can be through this open end, or through openings in the base, provided that the drive mechanism is properly enclosed. 

Motor nd Drive. The preferred prime mover for a fan is usually an electric motor. Eor fans of low to moderate power, V-belt drives are frequently employed. This permits selection of fans that can be operated over a wide range of speeds rather than being limited to motor synchronous speeds. Furthermore, change of speed is less expensive with V-belt drives. However, fans requiring powerful motors, 37—75 kW (50—100 hp) and higher, are generally directly connected to the motor and driven at synchronous speed. 

Some drawbacks to the weigh belt are that it is a zero-reference device and thus needs frequent caHbration (re-zeroing). Buildup on the belt and roUers affects accuracy and operation, as does belt tension and dusty or floodable materials. Flexible connections are required to isolate the feeder from upstream and downstream equipment, unless the belt feeder/weigh idler concept is used. 

In the Premier Mill the rotor is shaped hke the frustrum of a cone, similar to that in Fig. 20-53. Surfaces are smooth, and adjustment of the clearance can be made from 25 [Lm (0.001 in) upward. A small impeller helps to feed material into the rotor gap. The mill is jacketed for temperature control. Direct-connected hquid-type mills are available with 15- to 38-cm (6- to 15-in) rotors. These mills operate at 3600 r/min at capacities up to 2 mVh (500 gal/h). They are powered with up to 28 kW (40 hp). Working parts are made of Invar alloy, which does not expand enough to change the grinding gap if heating occurs. The rotor is faced with Stellite or silicon carbide tor wear resistance. For pilot-plant operations, the Premier Mill is available with 7.5- and 10-cm (3- and 4-in) rotors. These mills are belt-driven and operate at 7200 to 17,000 r/min with capacities of 0,02 to 2 mVh (5 to 50 gal/h). 

The number of speed reduetions is another way to classify conveyor drives. Most common of the speed-reduction methods is the two-step system, in which the motor is coupled to a speed reducer and the slow-speed shaft of the reducer is connected to the conveyor-drive shaft by a V belt or a roller chain. The second reduction not only permits the use of a simpler speed reducer but also allows a more flexible layout of the motor and reducer mounting plate. On many installations this eliminates the need for a specially designed drive mount. 

Most of the drivers used with the sliding vane compressor are electric motors. Variable speed operation is possible within the limits of vane speed requirements. The vanes must travel fast enough to seal against the cylinder wall but not so fast that they cause excessive wear. For the smaller units, under 100 hp, V-belts are widely used. Direct connection to a motor, however, is possible for most compressors and is used through out the size range. 

Pony motors are additional, small motors connected to the same fan shaft. They are typically about 1/4 the size of the full size motor. Pony motors do not lend themselves to gear box applications and are, therefore, primarily applied to belt drive applications. The big motor operates when full capacity is required and the small motor simply free wheels. At reduced capacity, the small motor operates and the big motor spins freely. 

Systems worn by a person are not included here. These include personal fresh air supply systems (with pressurized air flasks or connected to a central system by tubes), air belts, air vests, and breathing masks. 

Stationary engines (historic), damp pulsations Spoked hub, steel rim Massive, low-speed rotors, belt or shaft mechanical connection to application... 

Normal electric motor speeds run from the standard induction speeds for direct connection of 3600, 1800 and 1200 rpm to the lower speed standards of the synchronous motors, and then to the somewhat arbitrary speeds established by V-belt or gear drives. For some cases, the pump speed is set by the type of drivers available, such as a gasoline engine. 

General features same as steam, except drive ahvays through crankshaft speed gear increasers or reducers V-belts, or direct coupling connection to drive shaft. 

The blades are usually fixed pitch up to 48-in. diameter with applications for adjustable pitch above this size. Fixed pitch is used up to 60-in. diameter with aluminum fen blades when direct-connected to a motor shaft. Variable pitch is used with belts, gears, etc., between the fen shaft and the driver to allow for the possibilities of slight unbalance between blades due to pitch angle variation. Aluminum blades are used up to 300°F, and plastic is limited to about 160°-180°F air stream temperature. 

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