Particle study device

Claim 2

In a particle study device comprising a sensing zone, means for passing a fluid suspension of particles through said sensing zone and means for sensing the presence of the particles within the influence of said sensing zone and for producing a signal in response to each particle sensed, the improvement comprising means for ejecting a specific amount of the fluid sample containing a plurality of particles into a flow stream leading to said sensing zone, said ejecting means including means for receiving and temporarily storing a given amount of sample, a thermal expansion device mounted within said receiving and storing means, and means for supplying a predetermined amount of energy to said thermal expansion device to raise the temperature of said device to cause said device to expand thereby to eject a specific minute amount of fluid sample from said receiving and storing means.

Claim 3

The ejecting means according to claim 1 wherein said receiving and storing means is a syringe.

Claim 4

The ejecting means according to claim 1 wherein said receiving and storing means includes a body having a fluid receiving cavity therein and an opening in a wall of the body communicating with said cavity, said thermal expansion device being situated within said cavity.

Claim 5

The ejecting means according to claim 1 wherein said energy supply means includes a voltage source having good regulation to provide a substantially constant voltage independent of current drain.

Claim 6

The ejecting means according to claim 1 wherein said thermal expansion device includes an electric heating element, an expandable element which surrounds said heating element, which is made from a material having a given thermal coefficient of expansion and which has a given volume, and an insulating jacket surrounding said expandable element and said heating element.

Claim 7

The ejecting means according to claim 5 wherein said expandable element is made of silver.

Claim 8

The ejecting means according to claim 5 wherein said expandable element is made of beryllium oxide.

Claim 9

The ejecting means according to Claim 5 wherein said expandable element is made of silver and beryllium oxide.

Claim 10

The ejecting means according to claim 5 wherein said heating element is a wire conductor and said expandable element includes an elongated core on which said wire conductor is wound, said heating element and said core being embedded in a body which forms part of the expandable element.

Claim 11

The ejecting means according to claim 9 wherein said core and said body are made of the same material.

Claim 12

The ejecting means according to claim 1 wherein said thermal expansion device includes an electric heating element and said energy supply means includes a voltage source, an energy storing device for storing a predetermined amount of energy and switch means for connecting said storage means to said heating element to discharge said predetermined amount of energy from said storage device into said electric heating element.

Claim 13

The ejecting means according to claim 1 wherein said thermal expansion device includes an electric heating element and said energy supply means includes a voltage source, switch means for connecting said voltage source to said heating element and circuit means connected to said switch means and said heating element for monitoring the energy input to said heating element and for opening the connection between said voltage source and said heating element after a predetermined amount of energy has been supplied to said heating element.

Claim 14

The ejecting means according to claim 12 wherein said circuit means includes means for intergrating the current blowing through said heating element, a second voltage source, a relay including an operating coil and contacts in the connection between said first voltage source and said heating element, and a comparator having inputs connected to said integrating means and said second voltage source and an output connected to said operating coil, said comparator being operable to compare a voltage developed in said integrating means with a constant voltage supplied from said second voltage source and to energize said coil for causing opening of said contacts when said developed voltage equals said constant voltage.

Claim 15

The ejecting means according to claim 1 wherein said receiving and storing means includes an elongate hollow body, a projection which extends from said body, which is integral with said body, which has a cavity therein communicating with the hollow interior of said body, and which has a tip at the distal end thereof, said tip having an opening therein communicating with said cavity, and a plunger in said body, said plunger having a passageway therein, said passageway having a first end which opens into said hollow body opposite a closed end of said hollow body and a second end which opens onto a side of said plunger and which is adapted to register and communicate with said cavity during at least a portion of the movement of said plunger within said body, and said thermal expansion device being situated in said cavity.

Claim 16

The ejecting means according to claim 14 wherein said body is open at one end opposite said closed end and said plunger has a portion thereof which extends outwardly from said open end of said body, and wherein said receiving and storage means includes means for limiting outward movement of said plunger to a position where said second end of said passageway is completely out of registry with said cavity.

Claim 17

The ejecting means according to claim 14 including means for mounting said body in said particle study device with said tip in a predetermined position relative to said sensing zone in said particle study device.

Claim 18

The ejecting means according to claim 1 wherein said receiving and storing means includes an elongate hollow body and a projection which extends from said body, which is integral with said body, which has a cavity therein communicating with the hollow interior of said body, and which has a tip at the distal end thereof, said tip having an opening therein communicAting with said cavity, and said body having a hole therein opposite said projection and wherein a plunger is received in said body through an open end thereof and has a lateral passageway therethrough which is adapted to be brought into registry with the inner end of said cavity for enabling filling of said cavity with fluid sample through said hole and said passageway.

Claim 19

The ejecting means according to claim 17 wherein the end of said body, opposite said open end thereof is closed, and said plunger has at least one channel therein communicating the space betwen said closed end of said body and the inner end of said plunger to atmosphere.

Claim 20

The ejecting means according to claim 1 including means for mounting said ejecting means in position for ejecting the specific minute amount of fluid sample toward said sensing zone in said particle study device.

Claim 21

In a particle study device of the type wherein a fluid sample containing particles is passed from one body of electrolyte through an aperture to another body of electrolyte, wherein the impedance through the aperture is changed during the passage of a particle through the aperture and wherein the change of impedance is sensed and used to generate an electrical signal representing a particle passing through the aperture, the improvement comprising means for ejecting a specific minute amount of fluid sample containing a plurality of particles into the first body of electrolyte and toward said aperture, said ejecting means including means for receiving and temporarily storing a given amount of fluid sample, a thermal expansion device mounted within said receiving and storing means, and means for supplying a predetermined amount of energy to said thermal expansion device to raise the temperature of said device and to cause said device to expand thereby to eject a specific minute amount of fluid sample, having a volume equal to the volume increase of the expanded thermal expansion device, from said receiving and storing means.

Claim 22

In a particle study device of the type wherein a fluid sample containing particles is passed from one body of electrolyte through an aperture to another body of electrolyte, wherein the impedance through the aperture is changed during the passage of a particle through the aperture and wherein the change of impedance is sensed and used to generate an electrical signal representing a particle passing through the aperture, the improvement comprising means for ejecting a specific minute amount of fluid sample containing a plurality of particles into the first body of electrolyte and toward said aperture, said ejecting means including means for receiving and temporarily storing a given amount of fluid sample, a thermal expansion device mounted within said receiving and storing means, and means for supplying a predetermined amount of energy to said thermal expansion device to raise the temperature of said device and to cause said device to expand thereby to eject a specific minute amount of fluid sample, having a volume equal to the volume increase of the expanded thermal expansion device, from said receiving and storing means.

Claim 23

A particle study device according to claim 1 wherein said ejecting means includes means for mounting said ejecting means in a predetermined position relative to said aperture such that an outlet orifice of said ejecting means from which fluid sample is ejected is located closely adjacent said aperture and such that said outlet orifice is coaxial with said aperture.

Claim 24

A particle study apparatus comprising a sensing zone, means for passing a fluid suspension of particles through said sensing zone and means for sensing the presence of the particles within the influence of said sensing zone and for producing a signal in response to each particle sensed, said means for passing the fluid suspension through said sensing zone including means for ejecting a specific minute amount of fluid sample containing a plurality of particles into a flow stream leading to said sensing zone, and said ejecting means including means for receiving and temporarily storing a given amount of sample, a thermal expansion device mounted within said receiving and storing means, and means for supplying a predetermined amount of energy to said thermal expansion device to raise the temperature of said device to cause said device to expand and increase in volume thereby to eject a specific minute amount of fluid sample from said receiving and storing means, the volume of said specific minute amount of sample being equal to the volume increase of said thermal expansion device.

Claim 25

A particle study apparatus comprising a sensing zone, means for passing a fluid suspension of particles through said sensing zone and means for sensing the presence of the particles within the influence of said sensing zone and for producing a signal in response to each particle sensed, said means for passing the fluid suspension through said sensing zone including means for ejecting a specific minute amount of fluid sample containing a plurality of particles into a flow stream leading to said sensing zone, and said ejecting means including means for receiving and temporarily storing a given amount of sample, a thermal expansion device mounted within said receiving and storing means, and means for supplying a predetermined amount of energy to said thermal expansion device to raise the temperature of said device to cause said device to expand and increase in volume thereby to eject a specific minute amount of fluid sample from said receiving and storing means, the volume of said specific minute amount of sample being equal to the volume increase of said thermal expansion device.

Claim 28

The method according to claim 23 including the steps of supplying electric energy to said thermal expansion device; monitoring the energy being supplied; and terminating the supplying of electric energy after a predetermined amount of electric energy has been supplied to said thermal expansion device.

Claim 29

The method according to claim 24 wherein the step of monitoring the electric energy supplied includes the steps of: integrating the current supplied to the thermal expansion device from a constant voltage source; and comparing the voltage developed by said integrating with a given voltage, said termination of the supplying of electric energy occurring when said developed voltage equals said given voltage.

Claim 30

The method according to claim 23 including the initial step of filling said chamber.

Claim 31

The method according to claim 26 wherein said step of filling said chamber consists essentially in sucking a quantity of a fluid sample containing particles into said chamber through said small orifice.

Claim 32

The method according to claim 26 wherein said chamber is formed in a body having an opening larger than said small orifice communicating with said chamber, and said step of filling said chamber includes the steps of introducing fluid sample containing particles through said opening into said chamber until said chamber is filled and then closing said opening.