Abstract:
Apparatus, systems, and methods related to a constant-flow control valve and BTU meter assembly that has a pressure independent, constant-flow control valve assembly connectable to the fluid-based heating or cooling system. A valve stem is connected to a valve member and is rotatable as a unit relative to a valve body to change the position of valve member to change a fluid flow rate through the valve. The valve member's position relative to the fluid path is directly related to the fluid flow rate. Pressure sensors measure the pressure of fluid entering and exiting the valve body. A BTU meter assembly is connected to the valve stem, which is rotatable relative to the BTU meter assembly. A position sensor of the BTU meter assembly detects a rotational position of the valve stem relative to the BTU body. A controller of the BTU meter assembly is coupleable to the position sensor, the pressure sensors, and the temperature sensors, and the controller determines the fluid flow rate based upon the pressure drop across the valve assembly and the rotational position of the valve stem. The controller also determines energy usage of the heating or cooling device based upon the flow rate and the temperature change across the heating or cooling device.
Abstract:
The invention relates to micro fuel cell systems whose performance is enhanced by an accurate fluid delivery system. The fluid delivery system improves reactant fluid provision to meet electrical output, while maintaining correct stoichiometries for chemical processing in a downstream reactor. The fluid delivery system includes a pressure source and a differential flow meter. The differential flow meter uses a flow restrictor and a sensor. The pressure source moves a fluid through the flow restrictor; the sensor detects differential pressure in the flow restrictor and outputs a signal that permits dynamic control of fluid flow, e.g., by controlling a pump.
Abstract:
The present invention provides microfluidic technology enabling rapid and economical manipulation of reactions on the femtoliter to microliter scale.
Abstract:
An apparatus having scattering and multi-color fluorescence detecting, analyzing and identification capabilities of blood or other fluids of interest. The sample to be tested may be entered in a disposable microfluidic cartridge (14) which in turn is insertable in a hand-holdable or implantable miniaturized and portable cytometer instrument (10). This cytometer has significant application in biological warfare agent detection, hematology and other clinical and research fields.
Abstract:
A valve assembly may include a main housing and first and second electro-statically actuated valves. The main housing may define at least three chambers, with a first chamber configured to be coupled to a high pressure supply port, a second chamber configured to be coupled to an output port, and a third chamber configured to be coupled to a low pressure exhaust port. The first electro-statically actuated valve may be provided between the first and second chambers, and the first electro-statically actuated valve may allow or substantially block fluid communication between the first chamber and the second chamber responsive to a first electrical signal. The second electro-statically actuated valve may be provided between the second and third chambers, and the second electro-statically actuated valve may allow or substantially block fluid communication between the second chamber and the third chamber responsive to a second electrical signal. Related methods are also discussed.
Abstract:
An adjustable flow field and flow regulation method for an electrochemical device such as a fuel cell is described. The flow field preferably includes a plurality of flow paths between an inlet and an outlet and a plurality of microvalves for regulating fluid flow through the flow paths in response to changes in the operating states of the fuel cell, such as changes in power output or temperature. For example, adjustment of the microvalves may restrict the number of flow paths through which fluid is flowing to alter the effective active area and current density of the flow field. The valves may be selectively opened or closed, either entirely or partially, to maintain a minimum pressure drop between the inlet and outlet. Alternatively or additionally, adjustment of the valves may alter the direction of fluid flow through at least some of the flow paths. The invention improves the stability of the fuel cell in low power and low reactant stoichiometry operating states without significantly increasing the complexity of the system or increasing parasitic loads. For example, the invention may improve water management in low power modes and avoid related performance problems such as low current density failures and voltage oscillations. The invention may also help reduce the cost and complexity of the system power electronics.
Abstract:
A surface-micromachined mass flow controller (MFC) comprises an electrostatically actuated microvalve integrated with a thermal flow sensor. The microvalve comprises a normally-open diaphragm defining an aperture allowing fluid communication between first and second flow channels. The diaphragm includes a second electrode actuable toward a valve seat including a first electrode. Fabricated utilizing a multilayer Parylene process, the active microvalve and the flow sensor are integrated onto a single chip to perform closed-loop flow control. For flow control, both Pulse Width Modulation (PWM) and actuation voltage adjustment are demonstrated.
Abstract:
The fluid filters and fluid flow regulators are capable of accurately handling substantially continuous fluid flow rates as low as about 0.01 cc/day. The filters and flow regulators are so miniaturized, corrosion-resistant and non-toxic that they are suitable for being implanted in the human body; and are capable of being mass produced at costs so low, by using micromachining techniques, such as etching, that they may be considered to be disposable. The filters and flow regulators are passive devices which consume no electrical energy at all. The filters and flow regulators are reliable because they may have as few as only two parts, only one which is a moving part; and because they may handle fluids at very low pressures.
Abstract:
Described embodiments provide devices, systems and methods for sequencing liquid flow in response to a driving force by entrapping and releasing gas between volumes of liquid in a controlled manner. In one particular form, a centrifugal "lab on a disk" device is provided to drive liquid flow and sequencing by virtue of the centrifugal force and in one particular form a radially inward bend conduit is used in connection with controllably trapping and releasing gas between liquid volumes.