Patent Application
20100102261
The invention relates to a valve. More particularly, the invention relates to a fluid valve mechanism applied to microfluidic pathways.
A valve is a device that regulates the flow of materials, such as gases, fluids, slurries, or liquids, by opening, closing, or partially obstructing various passageways. The valve includes a valve body and passages that allow flow into and out of the valve, typically referred to as ports. Ports are obstructed or opened by a valve member or disc to control the fluid flow. Valves with two or three ports are the most common, while valves with multiple ports are used in special applications. Nearly all valves are built with some means of external connection at the ports.
The valve body remains stationary within the fluid system, while the valve member is movable so as to control flow. A round type of disc with fluid pathway(s) inside that can be rotated to direct flow between certain ports is typically referred to as a ball. Ball valves are valves which use spherical rotors, except for the interior fluid passageways. Plug valves use cylindrical or conically tapered rotors called plugs. The plugs in plug valves have one or more hollow passageways going sideways through the plug, so that fluid can flow through the plug when the valve is open.
Two-port valves are commonly called two-way valves. Operating positions for such valves can be either closed so that no flow at all goes through, fully open for maximum flow, or sometimes partially open to any degree between fully open and closed. Three-way valves have three ports. Three-way valves are commonly made such that flow coming in at one port is directed to either the second port in one position, the third port in another position, or in an intermediate position so all flow is stopped. Three-way valves are often ball or rotor valves. Many faucets are three-way valves so that incoming cold and hot water can be regulated in varying degrees to output water at a desired temperature.
Many valves are controlled manually with a handle attached to the valve stem. If the handle is turned a quarter of a full turn (90°) between operating positions, the valve is called a quarter-turn valve. Butterfly valves, ball valves, and plug valves are often quarter-turn valves. Valves can also be controlled by devices called actuators. Various types of actuators include electromechanical actuators such as an electric motor or solenoid, pneumatic actuators that are controlled by air pressure, or hydraulic actuators that are controlled by the pressure of a liquid such as oil or water. Actuators can be used for the purpose of automatic control such as in washing machine cycles, remote control such as the use of a centralized control room, or to simply manual controls. Pneumatic actuators and hydraulic actuators need pressurized air or liquid lines to supply the actuator.
A check valve, also referred to as a clack valve, non-return valve, or one-way valve, is a valve that normally allows fluid (liquid or gas) to flow through in only one direction. Check valves are two-port valves, meaning there are two openings in the body, one for fluid to enter and the other for fluid to leave. There are various types of check valves used in a wide variety of applications. Check valves are turned on and off according to a threshold pressure, which is the minimum upstream pressure at which the valve will turn on. For pressures below the threshold pressure, the check valve turns off.
A diaphragm valve is typically used as a shut-off valve in process systems within the food and beverage, pharmaceutical and biotech industries. Conventional diaphragm valve designs are not well suited for regulating and controlling process flows.
There are many other conventional valves including a choke valve, an expansion valve, a gate valve, a globe valve, a knife valve, a needle valve, a piston valve, and a pinch valve. A choke valve lifts up and down a solid cylinder, which is placed around or inside another cylinder that has holes or slots. The choke valve is used for high pressure drops found in oil and gas wellheads. An expansion valve is used for pressure reduction of fluid. A gate valve is used primarily for on and off control, with low pressure drop. A globe valve is useful for regulating fluid flow. A knife valve is used with slurries or powders to provide on and off control. A needle valve is used for accurate flow control. A piston valve is used for regulating fluids that carry solids in suspension. A pinch valve is used for slurry flow regulation. Each of these valves is configured according to accommodate their specific applications.
A valve mechanism is configured to control fluid flow. The valve mechanism includes a rigid body structure through which various channel structures are configured. The channel structures include one or more inlet channels, one or more outlet channels, a plunger channel that couples the one or more inlet channels to the one or more output channels, and an actuation channel. A plunger is positioned in the plunger channel, movable between a first plunger position and a second plunger position. The input fluid flow is sufficient to move the plunger from the first plunger position to the second plunger position in the absence of any additional plunger retention force. In the first plunger position, the plunger blocks the fluid pathway between the one or more inlet channels to the one or more outlet channels. In the second plunger position, the fluid pathway is opened. An actuation element is positioned in the actuation channel. The actuation element moves between a first actuated position and a second actuated position. In the first actuated position, the actuation element, either directly or indirectly, applies a retention force to the plunger to retain the plunger in the first plunger position, thereby maintaining the valve mechanism in a closed position. In the second actuated position, the retention force applied to the plunger is removed, thereby enabling the plunger to be moved to the second plunger position, which changes the valve mechanism to an open position. A valve actuation mechanism is coupled to the actuation element to move the actuation element from the first actuation position to the second actuation position.
The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention but not limit the invention to the disclosed examples.
Embodiments of the valve mechanism are described relative to the several views of the drawings. Where appropriate and only where identical elements are disclosed and shown in more than one drawing, the same reference numeral will be used to represent such identical elements.
Reference will now be made in detail to the embodiments of the valve mechanism of the present invention, examples of which are illustrated in the accompanying drawings. While the present invention will be described in conjunction with the embodiments below, it will be understood that they are not intended to limit the invention to these embodiments and examples. On the contrary, the present invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the present invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to more fully illustrate the present invention. However, it will be apparent to one of ordinary skill in the prior art that the present invention may be practiced without these specific details. In other instances, well-known methods and procedures, components and processes haven not been described in detail so as not to unnecessarily obscure aspects of the present invention.
Embodiments of the present invention are directed to a valve mechanism for controlling fluid flow through a fluid pathway. The valve mechanism includes a rigid body structure through which various channel structures are configured. A valve actuation mechanism is coupled to the rigid body structure. The valve mechanism is actuated to move a plunger within a fluid pathway, thereby opening the fluid pathway through the valve mechanism. In some embodiments, the valve mechanism is configured as a single-use device, that is the valve mechanism is initially closed and when actuated, is open. Once open, the valve mechanism remains open, even when the valve actuation mechanism is disengaged. In this single-use embodiment, the valve mechanism is not configured to subsequently actuate from the open position back to the closed position, even if the valve actuation mechanism is re-engaged. As the valve mechanism remains open once the valve actuation mechanism is disengaged, the valve mechanism is configured as a power-saving device. The valve actuation mechanism is only powered on during the actuation movement that changes the valve mechanism from closed to open. Once the valve mechanism is open, the valve actuation mechanism is powered down. In some embodiments, the valve mechanism is configured as a two-way valve, which includes a single input channel, a single output channel, and a means for regulating fluid flow between the two channels. In other embodiments, the valve mechanism includes more than two channels, for example multiple input channels and/or multiple output channels, and a means for regulating fluid flow between the channels.
In general, the valve mechanism is configured for use within a fluid pathway, and therefore can be used within an apparatus or system including a fluid pathway. An exemplary application is to include the valve mechanism within an apparatus configured to process a fluid sample, such as a sample preparation apparatus described in the U.S. patent application Ser. No. (MFSI-01800), filed on Oct. 28, 2008, and entitled “A Sample Preparation Apparatus”, which is hereby incorporated in its entirety by reference.
The input channel 10 is coupled to an external fluid line (not shown) and receives an input fluid flow. The input channel 10 and the output channel 12 are coupled to the plunger channel 14 to form a fluid pathway through the valve mechanism 2. The output channel 12 is coupled to an external fluid line (not shown) to output fluid flow. The relative positions of each of the channels shown in
The actuation pin 30 includes a first, wide portion 32 and a second, narrow portion 34. The actuation pin 30 is configured to move within the actuation channel 16 along the y-axis. The actuation pin 30 moves from a first pin position, as shown in
When the actuation pin 30 is in the second pin position, the narrow portion 34 does not block the plunger 20 and the input fluid flow against the plunger 20 forces the plunger 20 away from the input channel 10. The plunger 20 is forced away from the input channel 10 until the back side 42 of the plunger 20 is forced against the plunger stopper 18, thereby reaching the second plunger position. In the second plunger position, the plunger 20 enables fluid flow through plunger channel 14 to the output channel 12, thereby enabling fluid flow through the valve mechanism 2. Depending on a shape of the actuation channel 16, the plunger channel 14, and the plunger 20, the plunger 20 occupies some or all of the common area 6 when not in the first plunger position, as in when the plunger 20 is in the second plunger position or when the plunger 20 is moving from the first plunger position to the second plunger position. When the plunger 20 is in the second plunger position, the actuation pin 30 is locked in the second pin position. As such, there is no further need to actuate the valve actuation mechanism, and the valve actuation mechanism is disengaged from the actuation pin 30. As long as there is input fluid flow, the plunger 20 is locked into the second plunger position by the force of the input fluid flow.
The narrow portion 34 of the actuation pin 30 has a smaller diameter than the wide portion 32. In some embodiments, the plunger channel 14, the actuation channel 16, the plunger 20, and the actuation pin 30 are configured as cylinders, and the actuation pin 30 includes a curved transition from the narrow portion 34 to the wide portion 32, where the curved transition matches the cylindrical curve of the plunger 20. In this configuration, while the actuation pin 30 is in the second pin position, the narrow portion 34 of the actuation pin 30 does not occupy the portion of the common area 6 through which the plunger 20 moves. However, the curved transition from the narrow portion 34 to the wide portion 32 does curve into another portion of the common area 6. Since the curved transition matches the shape of the plunger 20, the curved transition does not block the plunger 20 although the curved transition does occupy a portion of the common area 6. Although the narrow portion 34 is shown in
Although the plunger channel 14, the actuation channel 16, the plunger 20, and the actuation pin 30 are described above as having cylindrical shapes, and the actuation pin 30 includes a curved transition that matches the cylindrical curve of the plunger 20, other shapes and curved transitions are also contemplated.
Alternative configurations of a valve mechanism are also contemplated.
The input channel 110 is coupled to an external fluid line (not shown) and receives an input fluid flow. The input channel 110 and the output channel 112 are coupled to the plunger channel 114 to form a fluid pathway through the valve mechanism 100. The interconnect channel 146 couples the plunger channel 114 to the actuation channel 116. The output channel 112 is coupled to an external fluid line (not shown) to output fluid flow. The relative positions of the input and output channels shown in
A plunger 120 is positioned in the plunger channel 114. A spring 138 and an actuation pin 130 are positioned in the actuation channel 116. The actuation pin 130 includes a spring opening 136 into which fits a first end of the spring 138. A second end of the spring 138 is coupled to a surface 142 of the actuation channel 116. The spring 138 applies an outward force on the actuation pin 130.
The retaining pin channel 124 extends through the rigid body structure 104 along the y-direction. A retaining pin 118 fits within the retaining pin channel 124. The retaining pin 118 fits within a detent 132 of the actuation pin 130.
The plunger 120 is configured to move within the plunger channel 114 along the z-axis. The plunger 120 moves from a first plunger position, as shown in
While in the first pin position, a side surface 148 of the actuation pin 130 prevents the ball bearing 140 from moving out of the detent 122. In general, a float between the ball bearing 140 and the side surface 148 of the actuation pin 130 is less than a depth of the detent 122 in the plunger 120. In this manner, the ball bearing 140 maintains a retaining force on the plunger 120 while the actuation pin 130 is in the first pin position. The dimensions of the ball bearing 140 and the interconnect channel 146 are designed so as not to exceed the maximum amount of float. Without the side surface 148, the ball bearing 140 is forced out of the detent 122 by the pressure exerted on the plunger 120 by the input fluid flow.
The actuation pin 130 is configured to move within the actuation channel 116 along the z-axis. The actuation pin 130 moves from the first pin position, as shown in
In the first pin position, the side surface 148 of the actuation pin 130 is aligned with the interconnect channel 146, thereby retaining the ball bearing 140 in the detent 122 and preventing the input fluid flow from moving the plunger 120 away from the first plunger position. As such, maintaining the actuation pin 130 in the first pin position also maintains the valve mechanism 100 in the closed position.
When the actuation pin 130 is in the second pin position, a detent 134 in the actuation pin 130 is aligned with the interconnect channel 146. The detent 134 provides sufficient depth for the ball bearing 140 to clear the detent 122 in the plunger 120. The input fluid flow against the plunger 120 forces the plunger 120 away from the input channel 110, thereby providing lateral force on the ball bearing 140. Since the side surface 148 no longer prevents the ball bearing from moving laterally, the ball bearing 140 is forced into the detent 134. With the ball bearing 140 clear of the detent 122, the plunger 120 is forced downward into the second plunger position, as shown in
Although the movable retaining element 140 is described above as a ball bearing, it is understood that any conventional element can be used that can be laterally moved in response to the movement of the plunger 120 in the plunger channel 114. For example, the detent 122 can be configured with a ramp profile or cam, and the element 140 can be configured as a sliding rod or pin coupled to the ramp or cam.
As an alternative configuration, the valve mechanism 100 can be reconfigured to replace the actuation pin 130, the ball bearing 140, and interconnect channel 146 with a rotating plunger release barrel that has a cam surface. In a first barrel position, the plunger is latched into the first plunger position by the barrel, thereby preventing movement of the plunger due to the input fluid flow. In this first barrel position, the valve mechanism is closed. When the valve actuation mechanism is forced against the cam surface, the plunger release barrel rotates from the first barrel position to a second barrel position, thereby releasing the plunger so as to be moved by the input fluid flow. The input fluid flow forces the plunger from the first plunger position to the second plunger position. In the second barrel position, the valve mechanism is open.
The input channel 210 is coupled to an external fluid line (not shown) and receives an input fluid flow. The input channel 210 and the output channel 212 are coupled to the interconnect channel 206 to form a fluid pathway through the valve mechanism 200. The input channel 210 is coupled to the interconnect channel 206 via a conical surface 202. The plunger channel 214 is coupled to the interconnect channel 206. The valve spring arm channel 246 couples the valve spring base channel 224 to the actuation channel 216 and to the plunger channel 214. The output channel 212 is coupled to an external fluid line (not shown) to output fluid flow. The relative positions of the input and output channels shown in
A spring 238 is configured as a wire spring clip that includes a spring base 242 and two spring arms, a first spring arm 240 and a second spring arm 236. The spring base 242 is positioned in the valve spring base channel 224. The first spring arm 240 and the second spring arm 236 are positioned in the valve spring arm channel 246. As shown in
The actuation pin 230 is positioned in the actuation channel 216. The actuation pin 230 includes a narrow portion 232 and a tapered portion 252. The narrow portion 232 has a diameter that is smaller than a distance between the two spring arms 236 and 240 at the actuation channel 216 while the spring 238 is in the closed position. The actuation pin 230 is configured to move within the actuation channel 216 along the z-axis. The actuation pin 30 moves from a first pin position, as shown in
A plunger 220 is positioned in the plunger channel 214 and is configured to move within the plunger channel 214 along the z-axis. The plunger 220 moves from a first plunger position, as shown in
While in the first plunger position, a ball end 226 of the plunger 220 is pressed against a diaphragm 250, which flexes inward and seats against the conical surface 202, thereby blocking fluid flow from the inlet channel 210 to the outlet channel 212. The diaphragm 250 is fluid-resistant and flexible. In some embodiments, the diaphragm is made of rubber. The diaphragm 250 is coupled to the interconnect channel 206, and provides a fluid barrier between the interconnect channel 206 and the plunger channel 214. The diaphragm 250 effectively separates a wet-side (fluid flow-side) from a dry-side (plunger-side) allowing the valve materials to be isolated and free from bio-compatibility issues that might occur if contacted by the fluid.
The actuation pin 230 is coupled to a valve actuation mechanism 150 (
In the second plunger position, the plunger 220 and the diaphragm 250 are retracted from the conical surface 202, which enables fluid flow from the input channel 210, through the interconnect channel 206, to the output channel 212, thereby enabling fluid flow through the valve mechanism 200. When the plunger 220 is in the second plunger position, there is no further need to actuate the valve actuation mechanism 150, and the valve actuation mechanism 150 is disengaged from the actuation pin 230.
Compared with the valve mechanism 100, the valve mechanism 200 uses less force to open the valve and enable fluid flow. The valve release of the valve mechanisms 200 does not need to overcome the plunger-in-cylinder bore friction required to open the flow path, as in the valve mechanism 100. Because the diaphragm 250 is stretched to close the valve in the initial state, the diaphragm itself functions as a release spring to open the flow path when the retaining force is released (moving the actuation pin to the second pin position).
The present invention has been described in terms of specific embodiments incorporating details to facilitate the understanding of the principles of construction and operation of the invention. The specific configurations shown and the methodologies described in relation to the valve mechanism are for exemplary purposes only. Such reference herein to specific embodiments and details thereof is not intended to limit the scope of the claims appended hereto. It will be apparent to those skilled in the art that modifications may be made in the embodiment chosen for illustration without departing from the spirit and scope of the invention.
