Metering pump

Claim 2

In a metering pump for measuring the flow of a fluid, the combination of a variable-volume chamber which expands and contracts as fluid admitted thereto and withdrawn therefrom, respectively, means for reciprocatively altering the volume of the chamber including resilient means urging the chamber toward one direction of volume alteration at a rate determined by the externally-determined rate of the fluid flow and mechanical means for positively altering the chamber volume in the other direction, the mechanical means being ineffective to control the chamber volume during at least a part of the volume alteration in the said one direction, valve means for the chamber arranged to cause fluid flow therethrough upon reciprocative alteration of the chamber volume, and means for counting the alterations of the chamber volume, said counting means being effective only during alteration of the chamber volume in one of said directions.

Claim 3

The metering pump according to claim 1 wherein the pump is an inspirator for measuring the volume of fluid flowing into the chamber at an externally-determined rate, the said resilient means urges the chamber in the direction to expand the chamber volume, and the mechanical means contracts the chamber volume.

Claim 4

The metering pump according to claim 2 wherein the valve means including a normally-closed valve connected to the chamber and means for opening the valve while the chamber is being contracted.

Claim 5

The metering pump according to claim 1 wherein the pump is an inspirator for measuring the volume of a gas flowing into the chamber at an externally-determined rate, the chamber includes a movable wall for altering the chamber volume, the said resilient means urges the wall to expand the chamber volume, the mechanical means is arranged to move the wall to contract the chamber volume, said wall having an opening for the outflow of gas which is normally closed by a valve included in said valve means, said pump having means for opening the said valve when the mechanical means moves the wall to contract the chamber volume, an electrical contact movable with said wall and a second electrical contact movable with the mechanical means, said contacts being arranged to be closed when the mechanical means contracts the chamber volume and open during at least the major part of the movement of the wall to expand the chamber volume, and a control circuit containing, in series, a source of electrical power, said contacts, and an electrical motor, said electric motor being coupled to operate said mechanical means and the counter being coupled to the electric motor.

Claim 6

The metering pump according to claim 1 wherein the pump can expel fluid from the chamber at an externally-determined rate, the said resilient means urges the chamber to contract the chamber volume, and the mechanical means expands the chamber volume.

Claim 7

The metering pump according to claim 1 wherein the pump can expel a gas from the chamber at an externally-determined rate, the chamber includes a movable wall for altering the chamber volume, the said resilient means urges the wall to contract the chamber volume, the mechanical means is arranged to expand the chamber volume, said chamber having an inlet opening for the inflow of gas which is normally closed by a valve included in said valve means, said pump having means for opening the said valve when the mechanical means moves the wall to expand the chamber volume.

Claim 8

The metering pump according to claim 6 which includes an electrical contact movable with said wall, a second electrical contact movable with the mechanical means, said contacts being arranged to be closed when the mechanical means expands the chamber volume and open during at least a major part of the movement of the wall to contract the chamber, and a control circuit containing, in series, a source of electrical power, the said contacts, and an electric motor, said electric motor being coupled to operate said mechanical means and the counter being coupled to the electric motor.

Claim 9

The metering pump according to claim 1 wherein said valve means includes a pair of check valves of which one is arranged to admit fluid into the chamber and the other is arranged to exhaust fluid from the chamber, the latter valve being arranged to open only at a pressure within the chamber which is greater than a predetermined pressure within the chamber which is greater than the pressure within the chamber during inflow of fluid thereinto.

Claim 10

The metering pump according to claim 1 which includes an electrical control circuit having, in series, electrical contacts which are opened when the mechanical means moves in the said one direction and are closed when the mechanical means moves in the said other direction, said control circuit being arranged and connected to control the operation of an electric motor which is mechanically coupled to said counter and to the said mechanical means.

Claim 11

The metering pump according to claim 9 wherein the chamber includes a movable wall for altering the chamber volume, said electrical contacts are mounted one on the movable wall and the other on the said mechanical means, and the mechanical means includes a lever arm pivotally mounted and engagable with a part of the wall to close the contacts and move the wall to alter the chamber volume in the said other direction, said lever arm being actuated by the said electric motor through a cam mechanism.

Claim 12

In a metering pump for measuring the flow of a fluid, the combination of a variable-volume chamber having a movable wall which expands and contracts the volume of the chamber as fluid is admitted and withdrawn therefrom, means for reciprocating said wall including resilient means urging the wall in one direction at a speed determined by the flow of fluid in one direction, as determined externally of the pump, and positive mechanical means for moving the wall in the opposite direction, the said mechanical means being ineffective to control the movement of the wall during at least a part of the movement of the wall in said one direction, valve means for said chamber for causing the fluid to flow therethrough upon reciprocation of the movable wall, and means for counting the movements of said wall including a counter and a circuit connected to the counter having electrical contacts movable with said wall and with said mechanical means, respectively, which contacts are opened to disable said counting means when the mechanical means moves in the said one direction and is separated from the movable wall.

Claim 13

In a metering pump for measuring the flow of a fluid, the combination of a variable-volume chamber having a movable wall which expands and contracts the volume of the chamber as fluid is admitted and withdrawn therefrom, means for reciprocating said wall including resilient means urging the wall in one direction at a speed determined by the flow of fluid in one direction, as determined externally of the pump, and positive mechanical means for moving the wall in the opposite direction, the said mechanical means being ineffective to control the movement of the wall during at least a part of the movement of the wall in said one direction, valve means for said chamber for causing the fluid to flow therethrough upon reciprocation of the movable wall, and means for counting the movements of said wall including a counter and a circuit connected to the counter having electrical contacts movable with said wall and with said mechanical means, respectively, which contacts are opened to disable said counting means when the mechanical means moves in the said one direction and is separated from the movable wall.

Claim 14

The metering pump according to claim 11 wherein said mechanical means is a lever arm pivotally mounted for engaging the movable wall and activated by a cam which is driven by an electric motor, said lever arm carrying at a part thereof which is engagable with a part of the wall one of said electrical contacts, the movable wall carrying the other of said contacts, and said counting means in coupled to said electric motor, said circuit including a source of electrical power, said motor and said contacts.

Claim 15

The metering pump according to claim 1 wherein said valve means is mechanically actuated in at least one of its closed and opened conditions, said actuation being synchronized with the alterations of the volume of said chamber.