Patent Application
20100051716
1. Field of the Invention
The present invention relates to a liquid additive injection pump powered by a fluid motor driven by a primary fluid stream to which the liquid additive is to be injected. More specifically, the present invention relates to an automated switch which can engage a mechanism which selectively suspends injection of the liquid additive.
2. Description of Related Art
Fluid powered motors driving an additive injection pump connected to a source of fluid additives are typically installed in a line containing primary fluid under pressure. Typically, the primary fluid produces reciprocating movement of a piston assembly within a housing of the fluid motor. The fluid motor in turn reciprocates a piston within a cylinder of the additive injection pump to draw a quantity of secondary fluid into the primary fluid. Such devices have been applied to add medication to drinking water for poultry and livestock, treat water with additives, add fertilizer concentrate to irrigation water, or add lubricant or cleaning agents to water. In liquid additive injection pumps, such as that shown in commonly owned U.S. Pat. No. 6,910,405, reciprocating movement of the piston assembly is produced by a valve mechanism operable to establish a differential pressure. Specifically, opening and closing of the valve mechanism synchronized to the upstroke and down stroke positions of the piston assembly produces a pressure differential that moves the piston through its reciprocating cycle. Opening and closing of the valve mechanism is synchronized to the piston assembly by an over-center mechanism, which is actuated coincident with the piston assembly reaching the ends of its upstroke and down stroke positions. The over-center mechanism is spring-biased and serves to toggle the valve mechanism open and closed when an actuating shaft carried by the piston assembly engages stops that define the ends of its upstroke and down stroke excursions. The '405 patent discloses a novel on/off switch located on the motor that engaged the motor. The '405 patent discloses a cam mechanism attached to the actuating shaft. When the switch is in the off position, the reciprocating movement of the piston is arrested.
As discussed above, pumps such as the one listed above are beneficial for many uses including irrigation and providing drinking water for livestock. Often these applications are useful in remote places wherein they are inaccessible to electricity or a place wherein the application of electricity is impractical. Thus, one benefit of such pumps is that running electricity to said pumps is unnecessary as the driving force is provided by the primary fluid. However, because the pumps are often remotely placed, manually turning the pump on and off can prove difficult and or time consuming; it may be desirable to control a remotely placed pump from a location other than where the pump is located. Furthermore, because the switches are typically located at the pump, a person can only turn a single pump on or off at a time. There are several applications, such as a car wash, for example, wherein it may be desirable to control several pumps at a single time and without electric sensors or motors. Accordingly, the present invention provides a system whereby a liquid additive injection pump may be controlled remotely and without the need for electric sensors or motors.
The present invention provides a system to inject a secondary fluid into a primary fluid. The system includes a fluid powered motor driven by a primary fluid stream. The fluid motor in turn drives a liquid additive injection pump to meter a secondary fluid. The fluid powered motor is provided with an automated on/off switch to suspend injection of the secondary fluid into the primary fluid by suspending operation of the fluid powered motor. The automated on/off switch comprises an actuator coupled with a fluid source and an actuating shaft, or any other apparatus to maintain primary and secondary fluids in communication. The actuator position of on or off is determined by the pressure of the fluid source. The actuator axially displaces the actuating shaft which either engages or suspends operation of the pump. When the actuator is in the on position, the actuating shaft is so axially displaced such that the fluid powered motor can engage and the secondary fluid is injected into the primary fluid stream. However, when the actuator is in the off position, the actuating shaft is so displaced such that the fluid powered motor is prohibited from engaging.
The pressure in the actuator can be controlled by controlling a valve positioned between the actuator and the pressurized fluid source. The valve can be remotely controlled to adjust the pressure within the actuator.
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein:
Several embodiments of Applicants' invention will now be described with reference to the drawings. Unless otherwise noted, like elements will be identified by identical numbers throughout all figures.
Returning to
Still referring to
The internal components of the fluid powered motor 10 within the housing 12 include a piston assembly 24. A valve mechanism 26 is carried on the piston assembly 24 and includes poppet valves 26A-26D. An actuator shaft 28 extends through the piston assembly 24 and is coupled to an over-center mechanism (not shown) that actuates the valve mechanism 26. Opening and closing of the valve mechanism 26 at the upstroke and down stroke positions of the piston creates a differential pressure within the housing 12 effective to produce reciprocating movement of the piston assembly 24. The internal components of the fluid powered motor 10 constitute what is termed a “differential pressure reciprocating piston assembly.”
At the top of the housing 12 is an automated on/off switch mechanism 32. Such a mechanism is used to selectively suspend and engage operation of the fluid powered motor 10. The switch mechanism 32 as well as the actuator 41, in one embodiment, has two positions: an on position and an off position. As will be discussed in detail below, the position of on or off is determined by the pressure of the fluid source. Thus, both the actuator and the switch mechanism are in communication with the fluid source. A sleeve 34 extends from the top of housing 12. A shaft plug 36 (not shown) is axially movable relative to the sleeve 34. The shaft plug 36 is coupled to both the actuator shaft 28 and the actuator 41. The actuator 41 is further coupled to the coupling line 51. The actuator 41 is secured to the upper housing 12 via actuator brackets 33. As will be discussed below, the axial displacement of the actuator shaft 28 controls the operation of the fluid powered motor 10. Thus, the axial displacement of the actuator shaft 28 and the coupled shaft plug 36 provides visual indicia of whether the fluid powered motor 10 is on or off. Accordingly, in one embodiment the actuator brackets 33 comprise an indicator 59. As used herein an “indicator” is any visual indicia of the pump's operation status. In the embodiment shown, the indicator 59 is a hole in the bracket through which the displacement of the shaft plug 36 can be monitored. In such an embodiment, when aligned in the on position, for example, an indicator such as a green dot located on the shaft plug 36 will be visible through the indicator 59. Likewise, when aligned in the off position a red dot will be visible through the indicator 59. Other embodiments useful for indicating the status of the pump may also be employed. For example, a pressure gauge may be attached to the actuator 41, indicating whether the actuator is pressurized. Regardless of the embodiment employed, the goal is to provide visual indicia of the pump's status. The operation of the actuator 41 will next be discussed in reference to
Referring now to
It should be noted that many of the internal components of the fluid powered motor 10 are not shown in
In the embodiment depicted, the actuator 41 has two extreme positions. In the first extreme position, the actuator 41 is in its natural state and does not apply any downward force. It can be seen that springs 58 provide an upward force on the platform 57. The upward force, when not counteracted as described below, keeps the platform 57 elevated within the actuator 41. In so doing, the actuator shaft 28 is either raised slightly, or at the least is not pushed downward. As will be discussed in detail below, in one embodiment such an action or inaction, prevents the fluid powered motor 10 from engaging. Alternatively, in the second extreme position, a force is applied which lowers the platform 57 downward within the actuator 41. This force, which counteracts and overcomes the upward force provided by the springs 58, causes both the shaft plug 36 and the actuator shaft 28 to be moved downward relative to the fluid powered motor 10. As will be discussed in detail below, such an action allows the fluid powered motor 10 to engage. Because, in this embodiment, a force is needed to turn the fluid powered motor 10 to the “on” position, the switch can be considered a fail safe device. In other words, if an outside source disrupts the force applied within the actuator 41 which causes the fluid powered motor 10 to engage, the fluid powered motor 10 will cease to engage. It should be noted that while one embodiment is generally described wherein a downward force engages the fluid powered motor 10, the invention is not so limited. For example, in other embodiments it may be desirable that an upward force engage the fluid powered motor 10. Thus, while reference is generally made to the actuating shaft 28 being axially displaced downward relative to the housing 12 to turn the pump on, the opposite is true in some embodiments. For example, in some embodiments, the actuating shaft 28 is axially displaced upward relative to housing 12 to turn the pump on. The instant invention discloses an apparatus and method whereby the actuator 41 position of on or off is determined by the pressure of a fluid source and the resulting axial displacement of the actuator shaft 28. Again, in some embodiments the actuator 41 is pressurized to engage the pump whereas in other embodiments the actuator 41 is depressurized to engage the pump. References to one application should not be interpreted as limiting. Thus, while the instant invention generally discusses one embodiment wherein to turn the pump on the actuator 41 is pressurized and the actuator shaft 28 is displaced downward relative to housing 12, it should be appreciated that this discussion is for illustrative purposes only and should not be deemed limiting.
It should also be noted that, while the embodiment shown discloses springs 58 which are attached to the platform 57, the current invention is not so limited. Any arrangement which provides for both a first extreme position wherein the actuator shaft 28 does not engage the fluid powered motor 10 and a second extreme position wherein the actuator shaft 28 engages the fluid powered motor 10 will suffice.
In the embodiment shown, the coupling line 51 is in fluid communication with the actuator 41. The coupling line 51 is also in fluid communication with a three-way solenoid valve 52. The three-way solenoid valve 52, in the embodiment shown, has a supply port coupled to a high pressure supply line 54, and two outlet ports including the purge line 53 and the aforementioned coupling line 51. Thus, the pressure in the actuator 41 is adjusted by controlling the solenoid valve 52. Solenoid valves are well known in the art, and use an electric current to control the operation of the valve. In one embodiment when it is desired that the pump is “on”, the solenoid valve connects the high pressure supply line 54 with the coupling line 51. The pressure from the coupling line 51, i.e. the actuating fluid, acts upon the platform 57 within the actuator 41 and provides a downward force. Thus, in operation, there is positive pressure exerted on the platform 57. As stated above, in such an embodiment when in the “on” position, the actuating shaft 28 is displaced downward which engages the fluid powered motor 10. However, when it is desired to stop the pump, the pressure within the actuator 41 must be relieved or depressurized. To do so, the three-way solenoid valve is adjusted to couple the coupling line 51 with the purge line 53. This allows the pressure in the actuator 41 to be relieved and stops the pump. Thus, in the “off” position, the actuating shaft 28 is not displaced downward, and the fluid powered motor 10 is not engaged.
Preferably, the purge line 53 is open to atmosphere to allow the pressure within the actuator 41 to reach about atmospheric pressure. In a preferred embodiment the three-way solenoid valve 52 is a fail safe valve which couples the high pressure supply line 54 with the purge line 53 in the event of low or interrupted current. It should be noted that while the embodiment described comprises a three-way solenoid valve, other valves known in the art will also suffice. For example, rather than one three-way solenoid valve, a plurality of two-way solenoid valves may be utilized. It should be noted that while an embodiment has been described utilizing a solenoid valve, the invention is not so limited. Other valves, both manual and automated, may be successfully employed to control the pressure within the actuator 41. As has been discussed, and will be discussed in more detail below, these valves can be located at the pump or at a distance removed from the fluid powered motor 10.
The fluid within the high pressure supply line 54, i.e. the actuating fluid, may come from a variety of fluid sources. In a preferred embodiment, the high pressure supply line 54 is coupled with the primary stream. In one embodiment, the high pressure supply line 54 is an off shoot from the inlet conduit 14. Thus, in such an embodiment, the actuating fluid is the same fluid as the primary fluid. For example, in such an embodiment, if water is driving the fluid powered motor 10, then water is also providing the pressure necessary to allow the actuator 41 to engage or disengage the fluid powered motor 10. In other embodiments, the high pressure supply line 14 is coupled with other fluid sources such as air. As used herein, “air” includes air in the traditional sense, i.e. breathing air, as well as other known gasses, including but not limited to, carbon dioxide, nitrogen, and oxygen.
Automated valves, such as the solenoid valve 52 depicted, typically require an electric current to operate. Thus, in one embodiment the three-way solenoid valve 52 is coupled to an electrical source through wire 55. The wire 55 is also coupled to a control or switch (not shown) which controls the electric current running to the three-way solenoid valve 52. This control or switch can be located far from the fluid powered motor 10 so that the fluid powered motor 10 can be started from a great distance from the pump. Additionally, the switch or control can be controlled via a computer which is capable of operating several fluid powered motors 10 at one time and in a variety of ways. For example, for some uses, such as a car wash, it may be desirable to add different additives to a fluid stream in varying points in a car wash. A computer can start and stop different fluid powered motors 10 at different times to accompany the many different additives desired. A further benefit is that the only electrical component is the wire connected to the three-way solenoid valve 52, or other suitable valve.
In many situations it may be undesirable to have a wire and a current source close to the fluid powered motor 10. For example, if the fluid powered motor 10 is being used in either a car wash or a swamp, delivering current through a wire may be difficult or unadvisable. Further, often laying electric wire 55 across remote land can be prohibitively expensive. The present invention provides many ways to overcome this problem. First, the valve can be placed outside of the wet environment. For example, keeping with the car wash scenario, the valve can be located either in the control room of the car wash or outside of the car wash. Thus, the high pressure line 51 may be extended as necessary to allow the valve to be centrally located compared to the fluid powered motor 10. Again, this will also eliminate the necessity of having electric wires 55 running all the way to the fluid powered motor 10. As discussed above, often running electric wire 55 is very expensive. In many applications it may be less expensive or more practical to run longer pipes (both coupling line 51 and high pressure supply line 54) than electric wire 55.
Another option of eliminating the need for electric wire 55 is to couple the valve 52 to a separate power source such as a battery or other means. As used herein a “separate power source” includes any power source which is not coupled to an electric grid. For example, the power source may comprise a battery coupled with solar panels. The power source may further be coupled with a remote receiver which may be controlled remotely via a remote control. Likewise, the valve may be coupled and controlled by a remote control. Thus, a fluid powered motor 10 can be located in a remote location without access to electricity, and a user can turn the motor 10 on and off from a centralized location via remote control. Again, in such an embodiment the valve is controlled by a separate power source.
Regarding solenoid valves, there are a wide variety of solenoid valves, most of which can be employed with the current invention. While some solenoid valves require an electric current to remain open, others require an electric current to remain closed. Still other solenoid valves commonly referred to as direct acting solenoid valves only require full power for a short period of time when adjusting the valve and use only low power to maintain the valve in its adjusted position. These direct acting solenoid valves are especially helpful in embodiments utilizing a separate power source. A common problem with any application utilizing a separate power source is running out of power too frequently. Using a solenoid which conserves power and which requires minimal power to operate ensures that the separate power source has a sufficiently long life. It should again be noted, that while one embodiment has been described with solenoid valves, the instant invention can utilize a wide variety of valves. For example, in one embodiment the actuating fluid is air from an air tank. The automated valve located on the air tank, which is controlled remotely, pressurizes and depressurizes the actuator 41. In other embodiments, for example, in the car wash scenario, the valve is opened or closed by external forces such as the position of a car in the car wash. When the valve is opened, the actuator is either pressurized or depressurized. Those skilled in the art can appreciate the many ways the pressure in an actuator 41 can be adjusted to control the fluid powered motor 10.
The aforementioned method and system results in a fluid powered motor which can be remotely controlled. While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
