Exxonmobil blading pump
In an axial flow pump, blades have an airfoil section over which the fluid flows and pressure is developed. So, the blade is twisted as the radius changes. The performance characteristics of an axial flow pump is shown in the figure.
Also, the power requirement increases as the flow decreases, with the highest power drawn at the zero flow rate. This characteristic is opposite to that of a radial flow centrifugal pump where power requirement increases with an increase in the flow. Also the power requirements and pump head increases with an increase in pitch, thus allowing the pump to adjust according to the system conditions to provide the most efficient operation.
The main advantage of an AFP is that it has a relatively high discharge flow rate at a relative low head.
The effect of turning of the fluid is not too severe in an axial pump  and the length of the impeller blades is also short. This leads to lower aerodynamic losses and higher stage efficiencies.
These pumps have the smallest of the dimensions among many of the conventional pumps and are more suited for low heads and higher discharges. One of the most common applications of AFPs would be in handling sewage from commercial, municipal and industrial sources.
In sailboats, AFPs are also used in transfer pumps used for sailing ballast. In power plants, they are used for pumping water from a reservoir, river, lake or sea for cooling the main condenser.
In the chemical industry, they are used for the circulation of large masses of liquid, such as in evaporators and crystallizers. In sewage treatment , an AFP is often used for internal mixed liquor recirculation i. In agriculture and fisheries very large horsepower AFPs are used to lift water for irrigation and drainage. In East Asia, millions of smaller horsepower HP mobile units are powered mostly by single cylinder diesel and petrol engines.
They are used by smaller farmers for crop irrigation, drainage and fisheries. Impeller designs have improved as well bringing even more efficiency and reducing energy costs to farming there. The reversible motor 10 has a main shaft 12 with two ends. One end of the main shaft 12 is connected to a clockwise over running clutch 20 , which freewheels in the clockwise direction, and engages in the counterclockwise direction.
The clockwise over-running clutch has an output shaft In a presently preferred embodiment, the clockwise over-running output clutch 32 is connected to and drives a hydraulic pump The other end of the main shaft 12 is connected to a counter clockwise over-running clutch The counter clockwise over-running clutch 22 freewheels in the counterclockwise direction and engages in the clockwise direction.
In a preferred embodiment, the counterclockwise over-running clutch is connected to and drives an air compressor In this embodiment, the air compressor is the first stage of a ram air compressor with a ram air inlet 42 , and a ram air outlet In alternate embodiments, the main shaft 12 may be an alternate driving connection, such as gear or spline outputs. As can be seen from FIG.
In a presently preferred embodiment, the drive motor 10 is a dual speed reversible electric motor providing a different main shaft 12 output speed when the motor runs in a clockwise direction than when the motor runs in a counterclockwise direction.
Alternately, a variable speed reversible motor would provide equivalent multi-speed function, with greater power output flexibility. Also, in a presently preferred embodiment, the clockwise over-running clutch 20 is combined with a gear system not shown that reduces the speed of the clockwise over-running clutch output shaft 32 driving the hydraulic pump In a presently preferred embodiment, the gear system not shown combined with the clockwise over-running clutch 20 and driving the hydraulic pump 30 is a harmonic drive type of gear system.
The second drive motor 60 has an output shaft 62 in line with and, through intervening components, connected to the main shaft 12 of the reversible motor In a presently preferred embodiment, the second drive motor shaft 62 is connected to and drives a second stage air compressor The second stage air compressor 50 has a second stage inlet 52 , and a second stage outlet The second stage air compressor 50 is linked by a common shaft 64 to the air compressor In an alternative embodiment, the second drive motor 60 through its drive shaft 62 may be connected directly to the air compressor In a presently preferred embodiment, as shown in FIG.
In a presently preferred embodiment, the common shaft 64 is a quill shaft link to the main shaft 12 through the air compressor In the embodiment shown in FIG. When operating, the second drive motor 60 provides a base level of power to the air compressors 40 and 50 even when the reversible drive motor 10 is reversed and providing power to the hydraulic pump Otherwise, both the reversible drive motor 10 and the second drive motor 60 provide combined power directly to the air compressors 40 and 50 while the hydraulic pump 30 is at rest, with the clockwise over-running clutch 20 freewheeling.
For most of the on-ground and in-flight operational period for the aircraft, the reversible drive motor 10 provides power to the air conditioning system of the aircraft through air compressors 40 and During periods when substantial hydraulic power is required, such as for raising and lowering the landing gear, or extending or retracting flaps, the reversible motor 10 is reversed, driving the hydraulic pump 30 for the limited periods of time those systems are in operation, temporarily reducing power to the aircraft air conditioning system.
In an alternative embodiment, the drive motor 10 is suitably not reversible if the clockwise over-running clutch 20 is replaced by a conventional clutch, and the counterclockwise over-running clutch 22 is similarly replaced by a conventional clutch, together with clutch controllers. The clutch controllers ensure that the appropriate clutch is engaged for the desired mode of operation and the other clutch is disengaged.
That is, the clutch link to the hydraulic pump 30 is engaged when the hydraulic pump is being operated, and the clutch linked to the air compressor 40 is engaged when the air compressor is being operated. Because in most applications the hydraulic pump is operated at a different speed than the air compressor, in this configuration, the drive motor 10 is suitably a two-speed or variable speed drive motor, but need not be reversible.
In a further alternative embodiment of the present invention, the clockwise over-running clutch 20 , linked to the hydraulic pump 30 , is suitably omitted if a means is provided to unload the hydraulic pump 30 , such as by short circuiting the hydraulic pump, when hydraulic power is not needed or additional air compression power is needed.
Similarly, the counterclockwise over-running clutch 22 is suitably omitted if a means is provided to unload the air compressor 40 , such as aerodynamically unloading the air compressor by opening a large air bleed. In this embodiment, when hydraulic power is needed the air compressor 40 is unloaded, directing all of the drive motor 10 power to the hydraulic pump, and vice versa. Operating the invention without clutches, but with means to unload the hydraulic pump and the air compressor does not entail a reversible motor.
However, because the hydraulic pump and air compressor are usually operated at different speeds, a dual speed, multi speed, or variable speed drive motor is suitably used. It will be appreciated that varying configurations of the present invention suitably permit the invention to be used, for example, in confined spaces.
The motor has a shaft driving the main shaft through a pair of meshing gears The main shaft is linked through a first overrunning clutch to a shaft driving a hydraulic pump The main shaft is also linked to a second overrunning clutch linked to a second subsystem shaft driving an air compressor The system permits flexible physical configuration of the present invention as the motor driving the main shaft may be positioned laterally from or at angles to the main shaft The present invention may also incorporate gearing that changes the output speeds and torque provided to subsystems driven by the invention.
The motor drives a main shaft projecting from two ends of the motor When the second overrunning clutch engages it drives a second gear set The second gear set drives a second shaft which in turn drives an air compressor Thus, the system suitably may provide a variety of output speeds and torques to the two subsystems driven by the system , in this instance a hydraulic pump and an air compressor It will be appreciated that harmonic drive gear sets may suitably be utilized advantageously incorporating lightweight and co-axial gearing into a system of the present invention.
The main shaft at one end engages an overrunning clutch when the main shaft operates in a clockwise direction. The first overrunning clutch when engaged then drives a first output shaft driving a hydraulic pump The second overrunning clutch engages when the main shaft operates in a counter-clockwise direction.
When the second overrunning clutch is engaged it drives the harmonic drive by driving the input wave generator of the harmonic drive The wave generator engages an intermediate flex spline in a known manner, which in turn engages the circular spline or output spline of the harmonic drive This gears down output of the main shaft to a reduced speed at the second output shaft driven by the output spline The second output shaft in turn in this embodiment drives an air compressor It will be appreciated that the harmonic drive advantageously permits the main shaft to be co-axial with the second output shaft even as the output of the second output shaft is geared down through the harmonic drive The present invention can be incorporated into aircraft, thereby advantageously providing weight reduction and flexibility in driving aircraft subsystems.
The system suitably includes a reversible motor driving a main shaft that projects from both ends of the motor Output from the harmonic drive drives the hydraulic pump Hydraulic pressure from the hydraulic pump suitably may be used to drive various aircraft subsystems such as flap drive motors , or landing gear drive motors not shown. At the other end the main shaft connects with a second overrunning clutch that engages when the main shaft operates in a clockwise direction.
When the second overrunning clutch engages, the main shaft drives an air cycle machine for air-conditioning including two air compressors linked to each other to take air from an input , compress the air, cool the air, then re-expand the air further cooling the air, resulting in air-conditioned air output for use in the aircraft In this exemplary embodiment, in the manner described in connection with FIG.
The second motor drives the air cycle machine through a second input shaft co-axial with the main shaft as described above in reference to FIG. The second motor suitably may power the air cycle machine for air-conditioning even when the reversible motor is operating in an opposite direction driving the hydraulic pump While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention.