Micromachined fluid handling devices

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein said regulator does not comprise a coiled spring that is mounted in compression between said substrate and said flexure at a position surrounding said regulator seat;
• wherein, during operation of said regulator, there is a driving pressure of said fluid at said fluid inlet means;
• wherein, in response to an increase in said driving pressure, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure, wherein, in response to a decrease in said driving pressure said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure;
• and wherein said flexure's top surface is not exposed to said fluid during operation of said fluid flow regulator.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• and wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference;
• wherein said source of fluid comprises a reservoir containing a reservoir supply of said fluid;
• wherein said reservoir has an outlet;
• wherein, during use, said regulator is adapted to be located within said reservoir, with said regulator's fluid outlet means located over said reservoir's outlet;
• and wherein, during use, said regulator is adapted to be immersed in said reservoir supply of said fluid, with said reservoir supply of said fluid in direct contact with said flexure's top surface, to eliminate any need for said regulator to have a cover for said flexure's top surface.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator can and to exit from said regulator;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• and wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference;
• wherein said fluid flow regulator comprises a micromachined fluid flow regulator;
• wherein said membrane comprises a first layer that is etchable by a first etchant, and a second layer that is not etchable by said first etchant;
• wherein said second layer has a thickness about equal to said flexure;
• and wherein at least part of said first layer is micromachined away by said first etchant, to produce said flexure from said membrane.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• and wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference;
• wherein said regulator has a predetermined driving pressure difference operating range;
• and wherein, over said predetermined driving pressure difference operating range, said regulator has a maximum fluid flow in the range of from about 0.01 cc/day to about 20.00 cc/day;
• wherein said regulator seat comprises a micromachined regulator seat which has been etched into said substrate;
• wherein said fluid inlet means comprises a micromachined fluid inlet means;
• wherein said micromachined fluid inlet means comprises at least one micromachined area of said substrate which been etched into said substrate;
• and wherein said fluid inlet means further comprises at least one corresponding portion of said membrane which extends over said micromachined area.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• and wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference;
• wherein said regulator has a predetermined driving pressure difference operating range;
• and wherein, over said predetermined driving pressure difference operating range, said regulator has a maximum fluid flow in the range of from about 0.1 cc/day to about 2 cc/day;
• wherein said fluid flow regulator comprises a micromachined fluid flow regulator;
• wherein said regulator seat comprises a micromachined regulator seat which has been etched into said substrate;
• wherein said fluid inlet means comprises a micromachined fluid inlet means;
• wherein said micromachined fluid inlet means comprises at least one micromachined area of said substrate which been etched into said substrate;
• and wherein said fluid inlet means further comprises at least one corresponding portion of said membrane which extends over said micromachined area.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises;

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein said regulator does not comprise a coiled spring that is mounted in compression between said substrate and said flexure at a position surrounding said regulator seat;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference;
• wherein said regulator has a predetermined driving pressure difference operating range;
• wherein said regulator seat has a regulator seat radial width;
• wherein said regulator gap has a regulator gap height;
• wherein the ratio of said regulator seat radial width to said regulator gap height is about 200:1 and wherein when said regulator is subjected to a driving pressure difference which is in excess of said predetermined driving pressure difference operating range, said regulator reduces said fluid flow to a value which is less than said predetermined fluid flow range, as a safety measure, to help prevent fluid flows in excess of said predetermined fluid flow range.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein said regulator does not comprise a coiled spring that is mounted in compression between said substrate and said flexure at a position surrounding said regulator seat;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference;
• wherein said regulator has a predetermined driving pressure difference operating range;
• wherein when said regulator is subjected to a driving pressure difference which is in excess of said predetermined driving pressure difference operating range, at least a portion of said flexure is deflected against at least a portion of said regulator seat;
• and wherein said portion of said regulator seat supports said portion of said flexure, as a safety measure, to help prevent said flexure from being ruptured by said driving pressure difference which is in excess of said predetermined driving pressure difference operating range.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• and wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference;
• wherein said membrane's mounting portion is anodically bonded to said substrate.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat:
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• and wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference:
• wherein said regulator comprises at least one exposed portion which is exposed to said fluid during operation of said regulator;
• wherein said regulator further comprises a corrosion-resistant layer on at least part of said exposed portion;
• and wherein said corrosion resistant layer is anodically bonded to said exposed portion.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• and wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference;
• wherein said fluid inlet means comprises at least two inlet channels;
• wherein at least one of said inlet channels is a sealed inlet channel, which is sealed to prevent any flow of said fluid through said sealed inlet channel;
• and wherein said predetermined fluid flow range may be at least partially selected by selecting how many of said inlet channels is a sealed inlet channel.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• and wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference;
• wherein said fluid inlet means comprise an inlet channel;
• wherein at least a portion of said inlet channel follows a course;
• and wherein said course comprises a course selected from the group consisting of circular, spiral and sinuous.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein said regulator does not comprise a coiled spring that is mounted in compression between said substrate and said flexure at a position surrounding said regulator seat;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference;
• wherein said fluid outlet means comprises a laser drilled outlet port;
• wherein said laser drilled outlet port is automatically given a curved, non-cylindrical, venturi-like configuration by said laser when it is drilled by said laser, for better fluid flow through said outlet port;
• wherein said outlet port has an outlet port inlet and an outlet port outlet;
• wherein at said outlet port has a length measured between said outlet port inlet and said outlet port outlet;
• and wherein at least a majority of said outlet port's length comprises said curved, non-cylindrical, venturi-like configuration.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• and wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference;
• wherein said regulator seat, said flexure, and said regulator gap are elongated and extend from said fluid inlet means to said fluid outlet means;
• wherein at least a portion of said regulator seat, said flexure and said regulator gap follow a course from said fluid inlet means to said fluid outlet means, and wherein said course comprises a course selected from the group consisting of circular, spiral and sinuous.

A fluid flow regulator for maintaining a fluid flow from a source of fluid within a predetermined fluid flow range, wherein said regulator comprises:

• a substrate;
• a regulator seat located on said substrate;
• a membrane comprising at least one mounting portion secured to said substrate, and a flexure extending over said regulator seat, wherein said flexure has a top surface and a bottom surface;
• a regulator gap located between said flexure's bottom surface and a top surface of said regulator seat;
• fluid inlet means for permitting a fluid to enter said regulator from said source of fluid and to enter said regulator gap;
• and fluid outlet means for permitting said fluid to exit from said regulator gap and to exit from said regulator;
• wherein, during operation of said regulator, there is a driving pressure difference of said fluid between said fluid inlet means and said fluid outlet means;
• wherein, in response to an increase in said driving pressure difference, said flexure bows towards said regulator seat an increased amount, to reduce the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said increase in said driving pressure difference;
• and wherein, in response to a decrease in said driving pressure difference, said flexure bows towards said regulator seat a decreased amount, to increase the size of said regulator gap and to tend to hold said fluid flow within said predetermined fluid flow range, despite said decrease in said driving pressure difference;
• wherein said regulator seat, said flexure, and said regulator gap are elongated and extend from said fluid inlet means to said fluid outlet means;
• wherein said regulator gap has a height measured between said regulator seat and said flexure, a length, a width, and a length to width ratio;
• and wherein said length to width ratio of said regulator gap is selected to be in the range of from about 5:1 to 1000:1.

A flow switch for selectively controlling a fluid flow from a source of fluid, wherein said flow switch comprises:

• a substrate, a single membrane, and a switch gap;
• wherein said substrate comprises a mounting portion, an inlet switch seat, and outlet port means for permitting said fluid to flow from said inlet switch seat and out of said flow switch;
• wherein said membrane comprises a mounting portion, a resilient flexure which extends over at least a portion of said inlet switch seat, and an inlet port means in said single membrane;
• wherein said inlet port means in said single membrane is located over said inlet switch seat, and is for providing a fluid path from a source of said fluid to said inlet switch seat;
• wherein, at all times during operation of said flow switch when said fluid is flowing from said outlet port, all of said fluid that flows from said outlet port is supplied only by said inlet sort means in said single membrane;
• wherein said switch gap is located between said flexure and said switch seat;
• wherein said membrane and said substrate are secured together at their respective said mounting portions;
• wherein, when a positive driving pressure difference of said fluid across said flow switch, which is less than a predetermined driving pressure difference switch point, is applied to a top surface of said flexure and to said inlet port means, said fluid flows continuously into said flow switch through said inlet port means, flows continuously radially outwardly across a top surface of said inlet switch seat through said switch gap;
• and flows continuously out of said flow switch through said outlet port means;
• wherein, at said predetermined driving pressure difference switch point, said flexure automatically collapses against said inlet switch seat, to automatically close said switch gap, switch off said flow switch, and stop said fluid flow through said flow switch;
• and wherein, at a driving pressure difference across said flow switch which is less than said driving pressure difference switch point, said resilient flexure automatically moves away from said inlet switch seat, to automatically open said switch gap, switch said flow switch back on, and permit said fluid to flow continuously through said flow switch once again.

A flow switch for selectively controlling a fluid flow from a source of fluid, wherein said flow switch comprises:

• a substrate, a membrane, and a switch gap;
• wherein said substrate comprises a mounting portion, an inlet switch seat, and outlet port means for permitting said fluid to flow from said inlet switch seat and out of said flow switch;
• wherein said membrane comprises a mounting portion, a resilient flexure which extends over at least a portion of said inlet switch seat, and an inlet port means, which is located over said inlet switch seat, for providing a fluid path from a source of said fluid to said inlet switch seat;
• wherein said switch gap is located between said flexure and said switch seat;
• wherein said membrane and said substrate are secured together at their respective said mounting portions;
• wherein, when a positive driving pressure difference of said fluid across said flow switch, which is less than a predetermined driving pressure difference switch point, is applied to a top surface of said flexure and to said inlet port means, said fluid flows continuously into said flow switch through said inlet port means, flows continuously radially outwardly across a top surface of said inlet switch seat through said switch gap;
• and flows continuously out of said flow switch through said outlet port means;
• wherein, at said predetermined driving pressure difference switch point, said flexure automatically collapses against said inlet switch seat, to automatically close said switch gap, switch off said flow switch, and stop said fluid flow through said flow switch;
• and wherein, at a driving pressure difference across said flow switch which is less than said driving pressure difference switch point, said resilient flexure automatically moves away from said inlet switch seat, to automatically open said switch gap, switch said flow switch back on, and permit said fluid to flow continuously through said flow switch once again;
• wherein said source of fluid comprises a reservoir containing a reservoir supply of said fluid;
• wherein said reservoir has an outlet;
• wherein, during use, said flow switch is adapted to be located within said reservoir, with said flow switch's outlet port means located over said reservoir's outlet;
• and wherein, during use, said flow switch is adapted to be immersed in said reservoir supply of said fluid, with said reservoir supply of said fluid in direct contact with said flexure's top surface, to eliminate any need for said flow switch to have a cover for said flexure's top surface.

A flow switch for selectively controlling a fluid flow from a source of fluid, wherein said flow switch comprises:

• a substrate, a membrane, and a switch gap;
• wherein said substrate comprises a mounting portion, an inlet switch seat, and outlet port means for permitting said fluid to flow from said inlet switch seat and out of said flow switch;
• wherein said membrane comprises a mounting portion, a resilient flexure which extends over at least a portion of said inlet switch seat, and an inlet port means, which is located over said inlet switch seat, for providing a fluid path from a source of said fluid to said inlet switch seat;
• wherein said switch gap is located between said flexure and said switch seat;
• wherein said membrane and said substrate are secured together at their respective said mounting portions;
• wherein, when a positive driving pressure difference of said fluid across said flow switch, which is less than a predetermined driving pressure difference switch point, is applied to a top surface of said flexure and to said inlet port means, said fluid flows continuously into said flow switch through said inlet port means, flows continuously radially outwardly across a top surface of said inlet switch seat through said switch gap;
• and flows continuously out of said flow switch through said outlet port means;
• wherein, at said predetermined driving pressure difference switch point, said flexure automatically collapses against said inlet switch seat, to automatically close said switch gap, switch off said flow switch, and stop said fluid flow through said flow switch;
• and wherein, at a driving pressure difference across said flow switch which is less than said driving pressure difference switch point, said resilient flexure automatically moves away from said inlet switch seat, to automatically open said switch gap, switch said flow switch back on, and permit said fluid to flow continuously through said flow switch once again;
• wherein said flow switch comprises a micromachined flow switch;
• wherein said membrane comprises a first layer that is etchable by a first etchant, and a second layer that is not etchable by said first etchant;
• wherein said second layer has a thickness about equal to said flexure;
• and wherein at least part of said first layer is micromachined away by said first etchant, to produce said flexure from said membrane.

A flow switch for selectively controlling a fluid flow from a source of fluid, wherein said flow switch comprises:

• a substrate, a membrane, and a switch gap;
• wherein said substrate comprises a mounting portion, an inlet switch seat, and outlet port means for permitting said fluid to flow from said inlet switch seat and out of said flow switch;
• wherein said membrane comprises a mounting portion, a resilient flexure which extends over at least a portion of said inlet switch seat, and an inlet port means, which is located over said inlet switch seat, for providing a fluid path from a source of said fluid to said inlet switch seat;
• wherein said switch gap is located between said flexure and said switch seat;
• wherein said membrane and said substrate are secured together at their respective said mounting portions;
• wherein, when a positive driving pressure difference of said fluid across said flow switch, which is less than a predetermined driving pressure difference switch point, is applied to a top surface of said flexure and to said inlet port means, said fluid flows continuously into said flow switch through said inlet port means, flows continuously radially outwardly across a top surface of said inlet switch seat through said switch gap;
• and flows continuously out of said flow switch through said outlet port means;
• wherein, at said predetermined driving pressure difference switch point, said flexure automatically collapses against said inlet switch seat, to automatically close said switch gap, switch off said flow switch, and stop said fluid flow through said flow switch;
• and wherein, at a driving pressure difference across said flow switch which is less than said driving pressure difference switch point, said resilient flexure automatically moves away from said inlet switch seat, to automatically open said switch gap, switch said flow switch back on, and permit said fluid to flow continuously through said flow switch once again;
• wherein said flow switch comprises a micromachined flow switch;
• wherein said outlet port means comprises a outlet cavity in said substrate;
• wherein said inlet switch seat is a micromachined inlet switch seat;
• wherein said outlet cavity is a micromachined outlet cavity;
• and wherein at least one of said micromachined inlet switch seat and said micromachined outlet cavity have been etched into said substrate.

A flow switch for selectively controlling a fluid flow from a source of fluid, wherein said flow switch comprises:

• a substrate, a membrane, and a switch gap;
• wherein said substrate comprises a mounting portion, an inlet switch seat, and outlet port means for permitting said fluid to flow from said inlet switch seat and out of said flow switch;
• wherein said membrane comprises a mounting portion, a resilient flexure which extends over at least a portion of said inlet switch seat, and an inlet port means, which is located over said inlet switch seat, for providing a fluid path from a source of said fluid to said inlet switch seat;
• wherein said switch gap is located between said flexure and said switch seat;
• wherein said membrane and said substrate are secured together at their respective said mounting portions;
• wherein, when a positive driving pressure difference of said fluid across said flow switch, which is less than a predetermined driving pressure difference switch point, is applied to a top surface of said flexure and to said inlet port means, said fluid flows continuously into said flow switch through said inlet port means, flows continuously radially outwardly across a top surface of said inlet switch seat through said switch gap;
• and flows continuously out of said flow switch through said outlet port means;
• wherein, at said predetermined driving pressure difference switch point, said flexure automatically collapses against said inlet switch seat, to automatically close said switch gap, switch off said flow switch, and stop said fluid flow through said flow switch;
• and wherein, at a driving pressure difference across said flow switch which is less than said driving pressure difference switch point, said resilient flexure automatically moves away from said inlet switch seat, to automatically open said switch gap, switch said flow switch back on, and permit said fluid to flow continuously through said flow switch once again;
• wherein said substrate's and membrane's mounting portions are anodically bonded to each other.

A flow switch for selectively controlling a fluid flow from a source of fluid, wherein said flow switch comprises:

• a substrate, a membrane, and a switch gap;
• wherein said substrate comprises a mounting portion, an inlet switch seat, and outlet port means for permitting said fluid to flow from said inlet switch seat and out of said flow switch;
• wherein said membrane comprises a mounting portion, a resilient flexure which extends over at least a portion of said inlet switch seat, and an inlet port means, which is located over said inlet switch seat, for providing a fluid path from a source of said fluid to said inlet switch seat;
• wherein said switch gap is located between said flexure and said switch seat;
• wherein said membrane and said substrate are secured together at their respective said mounting portions;
• wherein, when a positive driving pressure difference of said fluid across said flow switch, which is less than a predetermined driving pressure difference switch point, is applied to a top surface of said flexure and to said inlet port means, said fluid flows continuously into said flow switch through said inlet port means, flows continuously radially outwardly across a top surface of said inlet switch seat through said switch gap;
• and flows continuously out of said flow switch through said outlet port means;
• wherein, at said predetermined driving pressure difference switch point, said flexure automatically collapses against said inlet switch seat, to automatically close said switch gap, switch off said flow switch, and stop said fluid flow through said flow switch;
• and wherein, at a driving pressure difference across said flow switch which is less than said driving pressure difference switch point, said resilient flexure automatically moves away from said inlet switch seat, to automatically open said switch gap, switch said flow switch back on, and permit said fluid to flow continuously through said flow switch once again;
• wherein said flow switch comprises at least one exposed portion which is exposed to said fluid during operation of said flow switch;
• wherein said flow switch further comprises a corrosion-resistant layer on at least part of said exposed portion;
• and wherein said corrosion-resistant layer is anodically bonded to said exposed portion.