Patent Application
20120282114
The invention relates to an air pump and specifically to an air pump for moving and compressing air into an air storage tank.
Air pumps are used to transport a volume of air from one location to another. Air pumps that act as compressors are known to move and store a volume of air from one location to an air storage tank. When compressing and storing air considerable mechanical work may be required to store a required volume of air at a required pressure.
In order to store large volumes of air within a short amount of time, a large air pump is generally required in order to be able to move the required volume within the limited time. Smaller air pumps will generally only move a small volume of air and will therefore require more time in which to fill a large air storage tank.
The present invention provides an air pump comprising an internal by-pass system that allows air to flow directly from each air piston to the air storage tank depending on the pressure of the air moving between the pistons and the pressure head in the air storage tank.
In one embodiment, there is provided an air pump including a series of air pistons that are configured to pass air between adjacent pistons and to an air storage tank using a by-pass system.
In an alternative embodiment, there is provided an air pump configured to allow for movement of air to and from an air storage tank comprising a housing having at least one stem passing therethrough, the stem configured to reciprocate along its longitudinal axis within the housing, at least two air pistons located within respective air piston bores within the housing, each of the air pistons connected to the at least one stem and configured to reciprocate, along the longitudinal axis of the at least one stem, within its respective air piston bore, each air piston bore comprising a first air line fluidly connecting the air piston bore to the air storage tank and at least one second air line fluidly connecting the air piston bore to an adjacent air piston bore.
In an alternate embodiment, the air pump described herein further comprises an actuator for moving the at least one stem along its longitudinal axis within the housing. In one embodiment, the actuator is a hydraulic pump.
In an alternate embodiment, the first air line is configured to allow passage of air from the air piston bore to the air storage tank when the air leaving the air piston bore is of equal or greater pressure than the air in the air storage tank.
In a further embodiment, an air pump is provided that is configured to allow for movement of air to and from an air storage tank comprising a housing having a first and second stem passing therethrough, each of the stems configured to reciprocate along their longitudinal axis within the housing. The air pump further comprises a first air piston connected to the first stem and received within a first air piston bore located within the housing, the first air piston being operable to reciprocate within the first air piston bore along the longitudinal axis of the first stem; a second air piston connected to the first stem and received within a second air piston bore located within the housing, the second air piston being operable to reciprocate within the second air piston bore along the longitudinal axis of the first stem; a first air line, fluidly connecting the first piston bore to the air storage tank; a second air line, fluidly connecting the first piston bore to the second piston bore; and a third air line fluidly connecting the second piston bore to the air storage tank. The air pump further includes a third air piston connected to the second stem and received within a third air piston bore located within the housing, the third air piston being operable to reciprocate within the third air piston bore along the longitudinal axis of the second stem; a fourth air piston connected to the second stem and received within a second air piston bore located within the housing, the fourth air piston being operable to reciprocate within the second air piston bore along the longitudinal axis of the second stem; a fourth air line, fluidly connecting the third piston bore to the air storage tank; a fifth air line, fluidly connecting the third piston bore to the fourth piston bore; and a sixth air line fluidly connecting the fourth piston bore to the air storage tank.
In another embodiment, the air pump described above includes at least one actuator, for moving at least one of the first and second stem along its respective longitudinal axis within the housing. In an alternative embodiment, the air pump includes a first and a second actuator, the first actuator for moving the first stem along its respective longitudinal axis within the housing and the second actuator for moving the second stem along its respective longitudinal axis within the housing.
In an alternate embodiment, a method is provided for moving and compressing air using an air pump comprising a series of air pistons fluidly connected to each other and to an air storage tank, the method comprising (a) moving air between adjacent air pistons within the air pump and (b) allowing air to flow from each air piston to the air storage tank when the air pressure of the air leaving the air piston is equal to or exceeds the pressure in the air storage tank.
The present invention will now be described in further detail with reference to the following figures:
The present invention provides an air pump that moves and compresses air through a series of air pistons into an air storage tank at high pressure. The air pump includes a series of air pistons, connected by a common connecting rod, that simultaneously reciprocate to move air from one piston to the next for eventual storage in an air storage tank.
The air pump includes an internal by-pass system that allows air to flow directly from each air piston to the air storage tank depending on the pressure of the air moving between the pistons and the pressure head in the air storage tank. The by-pass system allows for large volumes of air to be passed directly to the air storage tank against low resistance, i.e. when the pressure in the tank is low, to provide rapid filling of the air storage tank. As the pressure rises in the air storage tank, the by pass system allows the air to pass between adjacent air pistons until the pressure of the air forced out of an air piston bore by an air piston is equal to or greater than the air pressure in the air storage tank. When this occurs the air will flow directly to the air storage tank. The by pass system allows the air pump, and particularly the air pistons to move the air efficiently for rapid filling of the air storage tank.
It will be understood that the use of the term “by-pass system” refers to the passage/flow of the air through the air lines that connect the air pistons within the air pump and that connect the air pump to the air storage tank, as described further below.
The air pump described herein may be configured to work as an air pump or a motor device. The air pump may include different configurations of pistons and connecting rods, e.g. single rod or split connecting rods, depending on the specific use of the air pump.
The air pump includes a series of pistons having decreased diameters which allows for staged compression of the air between adjacent pistons. The larger pistons are able to move larger volumes of air relative to the smaller pistons, however the air that is pumped out of the larger pistons is of a lower pressure than the air that is pumped out of the smaller pistons. The air pump, and in particular the by-pass system, allows for a larger volume of air to be pumped directly from the larger air piston to the air storage tank when the air pressure inside the air storage tank is at a low pressure. As the air pressure in the air storage tank increases the air is no longer able to flow directly from the larger piston and instead it flows to the adjacent smaller piston which is operable to pump air out at a higher pressure which is then able to flow to the air storage tank. As the air pressure increases in the air storage tank, only the air pumped from the smallest air piston is able to reach the same pressure as the air in the air storage tank and is therefore able to flow to the air storage tank. Once the air in the air storage tank reaches the maximum pressure setting, any excess air will blow-off via a pressure relief valve.
The present invention will now be described in detail with reference to the accompanying Figures.
One embodiment of a single stage air pump is shown in
Each of the air pistons 16, 18 and 20 and the hydraulic piston 14 are connected to the rod 22 so as to move simultaneously with the rod 22 and adjacent pistons.
Each piston 14, 16, 18 and 20 is received within a corresponding piston bore 24, 26, 28, 30 located within the housing 12. Each bore 24, 26, 28, 30 is sized to receive the corresponding piston 14, 16, 18, 20 and to allow for reciprocation of the piston 14, 16, 18, 20 within the bore 24, 26, 28, 30.
As can be seen in
It will be understood that the source of the hydraulic fluid may be any source that is operable to supply fluid at the required pressure to move the hydraulic piston 14 for use in the air pump 10. The operation and use of the air pump 10 will be described in further detail below. The hydraulic fluid enters the piston bore 24 through one of the hydraulic fluid inlets 32, 34, depending on the position of the hydraulic piston 14, and the pressure and amount of fluid initiates movement of the hydraulic piston 14 within the hydraulic piston bore 24.
As can be seen in
Each of the piston bores include respective air inlets and air outlets, referred to herein as air ports, shown clearly in
Each piston bore is divided, by the position of the piston within the piston bore, into two parts which are referred to herein as A and B. For example, in
Each of the respective air piston bores 26, 28, 30 are fluidly connected to the adjacent piston bore(s), and further are configured to be fluidly connected to an air storage tank 100, shown in
The configuration of the piston bores 26, 28, 30 being fluidly connected directly to the air storage tank 100 is referred to herein as the “by pass” system. It will be understood that the air pump 10 described herein can be operated with the by pass system turned on or off. The by pass system will work, i.e. air will flow through the air lines to the air storage tank 100, when there is no or low air pressure in the air storage tank 100. The by pass system allows air to flow to the tank when there is low or no pressure in the tank, which means that larger volumes of air are not handed off to the adjacent smaller piston. This eliminates the need to pass the air through adjacent pistons, and through further compression stages, and allows for more rapid filling of the air storage tank. This will be described in further detail below.
As stated above, each consecutive air piston 16, 28, 20 has a smaller diameter as you move from air piston 16 to air piston 20. Likewise the respective piston bores 26, 28, 30 are of decreasing overall volume. As a result of the decreasing size of the piston bores 26, 28, 30, each piston bore is able to hold a different volume of air and consequently the air leaving consecutive piston bores is forced out of the piston bores at consecutively higher pressures. It will be understood that all of the piston bores have the same depth in order for them to all accommodate the same stroke length.
For ease of reference, the hydraulic piston 14 is shown in the middle of a stroke in the centre of hydraulic piston bore 24. Fluid is operable to flow into the hydraulic piston bore 24 through one of the inlets 32, 34 and out through one of the outlets 36, 38.
Each of the air pistons 16, 18, 20 are shown in the centre of their respective piston bores 26, 28, 30 with parts A and B indicated within the piston bores. Each of the piston bores 26, 28, 30 are fluidly coupled to air ports that allow the air to flow into and out of the piston bores 26, 28, 30. It will be understood that each piston bore 26, 28, 30 includes four air ports connected to four air lines the air ports are shown in
As stated above, each of the piston bores 26, 28, 30 are connected to adjacent bores through a series of air lines and air ports. In addition, each of the piston bores 26, 28, 30 are also fluidly connected to the air storage tank 100 via a series of air lines. Each of the air lines includes at least one check valve which prevents air from flowing back along the air line. When the by pass system is “on”, the direction of the flow of the air through the air lines will be governed by the pressure of the air leaving the piston bore(s) and the head pressure in the air storage tank 100. When the head pressure in the air storage tank 100 is low, or when there is no air in the tank, the air that is forced out of piston bore 26 is able to flow directly to the air storage tank 100 since there is little or no resistance to its flow. The air storage tank 100 then begins to fill up with the air thereby increasing the head pressure within the storage tank 100. Since the volume of air that flows from the piston bore 26 is larger than the volume of air that flows from piston bore 30, it will be understood that air that flows directly from piston bore 26 will fill the air storage tank 100 at a greater rate than air that flows only from piston bore 30 to the air storage tank 100. This allows for large volumes of air to be moved directly into the air storage tank 100 from piston bore 26 providing rapid filling of the air storage tank 100.
Initially, when the pressure in the storage tank 100 is low the air leaving piston bore 26 will be able to flow directly to the storage tank 100. However, as the head pressure in the storage tank 100 increases, the air leaving piston bore 26 will be at too low a pressure to be able to flow directly to the air storage tank 100 and will instead flow directly to piston bore 28. The air leaving piston bore 28, which will be at a higher pressure then that leaving piston bore 26, may be able to flow directly to the air storage tank 100 due to its higher pressure. Therefore, air will continue to by-pass to the air storage tank 100 filling it up. Eventually, the pressure within air storage tank 100 will be high, due to the fact that the storage tank 100 has been filled with air flowing through the by pass system from the air pump 10. At this point, only air that leaves piston bore 30 will be at a pressure that allows the air to flow directly to the air storage tank 100.
It will be understood that the ability of the air pump 10 to pump air directly to the air storage tank 100 from the first piston bore 26 provides an air pump that moves and compresses air into the storage tank 100 at a greater rate than a traditional pump. The air pump 10 has the ability to move larger volumes of air, using the by pass system, against low resistance, in order to rapidly fill the air storage tank 100, when required.
As will be understood by the descriptions provided below, several configurations of the air pump 10 are described herein. However, it will be understood that the use of the air pump 10 is not limited to the examples provided and other configurations may be used.
The operation of the air pump will now be described in various configurations including the air pump mode with the by-pass system “off”, the air pump mode with the by-pass system “on” and the motor mode. It will be understood that reference is made generally to air lines that connect adjacent piston bores and/or the air storage tank and the piston bores, however the air lines described below, and identified in the figures are not meant to be limiting in any way. The air pump may comprise any series or combination of air lines that fluidly connect the piston bores and air storage tank as described herein. Reference to the specific air lines identified in the figures is provided to assist in the general understanding of the operation of the air pump. In the figures, the dashed lines indicate air lines that are dormant and the solid lines indicate air lines that are live. Solenoid valves are indicated generally by the symbol , showing a closed solenoid valve, and
showing an open solenoid valve. For ease of reference, solenoid valves are not specifically identified by numeral, however their use within the air lines will be understood clearly by a person skilled in the art and are discussed specifically where applicable.
With respect to the following discussions of the various configurations and modes of operation of the air pump, the fluid inlets and outlets and air ports which are referred to are clearly shown in
The operation of the air pump 10, in the air pump single stage with the by-pass system “off” configuration, will now be described with reference to
Movement of the hydraulic piston 14, which is connected to rod 22, initiates movement of the air pistons 16, 18, 20 which are also connected to rod 22. As air piston 16 begins to move within air piston bore 26 the air port 44, shown in
As stated above, movement of rod 22 translates into movement of all the adjacent air pistons 16, 18, 20. Therefore, when rod 22 moves, air piston 18 also moves within air piston bore 28 pushing the air that is located in air piston bore 28B out of air port 56, shown in
On the return stoke, shown in
Turning now to
As air piston 16 moves within air piston bore 26, air is forced from air piston bore 26A through air port 42, shown in
If the air pressure in air storage tank 100 is high, and at a pressure that is higher than the pressure of the air leaving air bore 26A, then the air will flow directly through to air piston bore 28A along air line 70 and will not be able to flow along air line 82 due to the greater resistance found in the air storage tank 100. As air piston 18 moves within air piston bore 28, air is forced from air piston bore 28B out of air port 56, shown in
If the pressure in the air storage tank is lower then the air pressure leaving air piston bore 28B then the air will flow directly to the storage tank 100 as well as through to piston bore 30B. If the pressure in air storage tank 100 is higher than the pressure of the air leaving air piston bore 28B then the air will flow directly into air piston bore 30B.
As air piston 20 moves within air piston bore 30, the air located in air piston bore 30A is pushed out of air port 62, shown in
Turning now to
As the pistons 16, 18, 20 begin to move in direction “R”, the air located in air piston bore 26B is pushed out of air port 40 by the movement of air piston 16 within air piston bore 26. The air flows out of air port 40 along air line 82 via air line 76 through to the air storage tank 100 and also into air piston bore 28B via air line 76, to prevent a vacuum forming in piston bore 28B. Likewise, the air located in air piston bore 28A flows out of air port 50 directly to the air storage tank 100 along air line 88 and also to piston bore 30A through air port 60, to prevent a vacuum within piston bore 30A. Air that is located in the piston bore 30B is pushed through air port 60 directly to the air storage tank 100, along air line 80, through the movement of air piston 20 within air piston bore 30.
As described above, the air pump 10 can operate as an air pump that moves and stores air, as described above with reference to
The operation of the air pump 10 will now be described in the motor mode or playback mode with reference to
In the playback mode, air is released from the storage tank 100 into piston bore 30A through air port 62, shown in
As the pistons 16, 18, 20 begin to move, the air in piston bore 30B will flow along air line 89 into piston bore 28B. The air in piston bore 28A flows into piston bore 26A via solenoid valve 110, located between, and in fluid communication with, piston bore 28A and 28B. It will be understood that solenoid valve 110 may alternatively be a separate air line connecting 28A and 28B that includes a solenoid valve within it. In order to avoid a vacuum being created in piston bores 28B air is fed through air line 71 into piston bore 28B.
On the return stroke, indicated by arrow “L” shown in
At the beginning of the stroke air is fed through air line 80 into piston bore 30B. As piston 20 moves within piston bore 30, in the direction of arrow “L”, the air that is in piston bore 30A is forced out and along air line 98 through to air line 88 which allows the air to flow from piston bore 30A to piston bore 28A. As piston 18 moves within piston bore 28, the air that is in piston bore 28B along air line 73 into piston bore 26B. As piston 16 moves within piston bore 26, the air that is in piston bore 26A is forced to ambient through air port 46 and solenoid valve 112.
On the next stroke, shown in
The movement of the air between the air pistons, and thereby the movement of the air pistons, drives the hydraulic piston, which in turn drives hydraulic fluid out of the hydraulic piston bore 24. In this motor mode, the next stroke then moves as that described in
It can therefore be seen that in the motor mode, or playback configuration, the air in the air storage tank can be used to drive the air pump, and specifically the air pistons, to in turn drive the hydraulic piston and eject the hydraulic fluid at a high pressure for use in another device or system.
Turning to
In another embodiment, shown in
Since each of the air piston sets 711, 713 include the use of separate hydraulic pistons 714, 715 through separate hydraulic fluid inlets 732, 733. Movement of each of the air piston sets 711, 713 may occur simultaneously, as shown in
The use of the split rod design allows for the offsetting of peak air pressures from both ends of the air pump simultaneously. In other words peak air pressure at one end of one of the air piston sets occurs at a different time to the peak air pressure exiting the end of the opposite air piston set. An example of the offset configuration is shown in
Turning to
, and solenoid valves that are open are represented by the symbol
.
Air flows between the air piston bores, entering through receiving ports, represented generally by numeral 820 and out of air piston bores through delivery ports, represented generally by numeral 830. The direction of the air flow, between adjacent air piston bores, is shown by the arrows in
On the return stroke, shown in
It will also be understood that in the split rod configuration, due to the separate hydraulic fluid feeds, it is possible to use only one side of the air pump, i.e. one of the rods with attached pistons, if required.
While the air pump, or sets of air pistons, in the above have been described in terms of including a series of three air pistons, it will be understood that the air pump disclosed herein is not limited to this configuration. For example the air pump may include a series of four or five or more air pistons. The air pump may also include only two air pistons. Other combinations of pistons within the air pump may be used while following the overall operation of the air pump disclosed herein.
In one embodiment, the air pump may include a central stem, or stems, having a series of pistons on one side that are greater in size than a series of pistons on the other side. Each series of pistons having pistons of decreasing diameter. In this configuration, the air is passed from the larger piston series across the pump to the smaller piston series. The overall flow of the air is therefore through a series of pistons that decrease in size, however, rather than being all in one row on one side of the air pump they are separated.
In operation, the air pump may be driven by hydraulic means or any suitable mechanical means that is operable to initiate movement of the pistons. While the air pump examples provided include the use of hydraulic means, it will be understood that alternative embodiments may be used that are operable to drive the stem and associated air pistons, such as a mechanical link connected to the hydraulic piston through a fluid link, oil coupling medium or through a direct mechanical connection.
Each of the air piston bores may include a pressure relief valve that monitors the pressure within the bore, or portion of the bore within which it is located. Such valves may be used to ensure that the pressure does not exceed the operational pressures allowed. Likewise, similar pressure relief valves may be used in the hydraulic piston bore(s).
It will be understood that while not specifically identified in the attached figures, each of the air lines may include one or more one-way valves or check valves to control the flow of air within each air line. In addition, where there is a requirement to control the input and/or output of air, solenoid valves may be used. One or more heat sinks may also be used to lower the air temperature for easier storage of the air in the air storage tank.
The air pump may include one or more cooling devices positioned to reduce the temperature of the air flowing through the air pump, and specifically between piston bores. Reducing the temperature of the air will allow for greater storage capacity in the air tank and will also reduce the impact on the hardware and extend the life of the components and reduce the maintenance required.
The air pump described herein may be used in any system that requires or uses a driving force, such as that supplied by the air pump in playback mode. The air pump may also be used in any system that requires rapid compression and storage of air.
As an example, when the air pump includes a hydraulic piston that is driven by an injection of hydraulic fluid, the injection of the fluid initiates movement of the stem within the air pump which drives the air pistons and compresses and stores air. In the playback mode, as described above, the air from the storage tank is used to drive the air pistons which in turn drive the hydraulic piston which ejects the hydraulic fluid from the hydraulic piston bore. The ejected hydraulic fluid can then be used to drive a device, system, that requires an input of hydraulic fluid, such as a hydraulic pump or a separate device. Alternatively, the air may be used to directly drive a device, such as an air motor.
As an example of a use of the air pump, the air pump may be connected to a vehicle braking system and the hydraulic fluid that drives the hydraulic piston is fed to the air pump during the braking action of the vehicle. In one embodiment, the air pump may be placed between the hydraulic source and the air tank to provide a source of braking and a pre-set restrictor valve may be used in the air line before the air tank. Hydraulic fluid moves the hydraulic piston, which in turn moves the air pistons, and the air that is pumped out of the air pump to the storage tank may be fed to the storage tank via a pre-set restrictor valve, i.e. a speed bump. The air flow opposition is transmitted back through the air pump to the hydraulic source, in this case the drive wheels and axle, thereby providing an additional source of braking.
While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modification of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments. Further, all of the claims are hereby incorporated by reference into the description of the preferred embodiments.
Any publications, patents and patent applications referred to herein are incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.
