Infusion device

Claim 2

A power module for a drug infusion device comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being of constant volume and being under partial vacuum and said first chamber containing a vacumm-stable viscous fluid therein; whereby, as said viscous fluid flows from said first chamber into said constant volume second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; and means for connecting said piston to a sryinge module for operating said syringe module as said piston advances from extended to retracted positions.

Claim 3

The power module of claim 1 in whih said casing has concentric cylindrical inner and outer walls; said second chamber being disposed within said inner wall and said first chamber being disposed between said inner and outer walls.

Claim 4

The power module of claim 2 in which said piston is annular and slidably engages opposing surfaces of said inner and outer walls.

Claim 5

The power module of claim 1 in which said viscous fluid undergoes a viscosity change at different temperatures within the operative temperature range of said module; said second chamber under partial vacumm containing a small amount of a volatitle fluid having an offsetting change in partial pressures within said operative range and being immiscible in said viscous fluid.

Claim 6

The power module of claim 1 in which said viscous fluid is polyisobutylene.

Claim 7

The power module of claim 1 in which said casing has concentric cylindrical inner and outer walls with said first chamber being disposed between said inner and outer walls and said second chamber being disposed within said inner wall; said piston being annular and slidably engaging opposing surfaces of said inner and outer walls; and detachable means temporarily joining said annular piston and casing for preventing rotation of said annular piston within said first chamber until said means is detached.

Claim 8

A syringe module adapted for connection to a power module as recited in claim 1, comprising a syringe barrel of generally cylindrical configuration having an outlet at one end for the discharge of a drug received in said barrel and having attachment means at its opposite end for irreversibly engaging the connecting means of a power module.

Claim 9

The syringe module of claim 7 in which said attachment means includes a plurality of circumferentially-spaced lugs adapted to be non-removably received in bayonet slots of a power module.

Claim 10

The syringe module of claim 8 in which said lugs are flexible and are provided with ratchet teeth.

Claim 11

The syringe module of claim 7 in which a resilient plunger is disposed within said barrel; said plunger having retraction means accessible through said opposite end of said barrel for gripping and retracting said plunger when said barrel is to be filled with a drug through said outlet.

Claim 12

The syringe module of claim 7 in which a plunger is slidably disposed within said barrel; a piercable membrane within said barrel adjacent said outlet; and a hollow needle within said barrel having a lumen communicating with said outlet and having a pointed tip for piercing said membrane as said plunger is advanced within said barrel.

Claim 13

A power module for a drug infusion devision comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; means for connecting said piston to a syringe module for operating said syringe module as said piston advances from extended to retracted positions; said casing having concentric cylindrical inner and outer walls; said second chamber being disposed within said inner wall and said first chamber being disposed between said inner and outer walls; said metering flow passage comprising an opening in said inner wall; said valve means comprising a valve member movably mounted in said casing for controlling flow through said opening.

Claim 14

A power module for a drug infusion devision comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; means for connecting said piston to a syringe module for operating said syringe module as said piston advances from extended to retracted positions; said casing having concentric cylindrical inner and outer walls; said second chamber being disposed within said inner wall and said first chamber being disposed between said inner and outer walls; said metering flow passage comprising an opening in said inner wall; said valve means comprising a valve member movably mounted in said casing for controlling flow through said opening.

Claim 15

The power module of claim 12 in which said valve means comprises a closure member rotatably received in said inner chamber and forming an end wall for said chamber; said opening in said inner wall being in the form of an elongated slot extending in the direction of rotation of said closure member.

Claim 16

The power module of claim 13 in which said closure member also has an elongated slot extending in the direction of, and alignable with, said slot of said inner wall.

Claim 17

The power module of claim 12 in which said valve means includes a closure member rotatably received in said casing and forming a wall portion of said inner chamber; said closure member having a partition with a port extending therethrough; and vacuum integrity indicating means comprising a resilient member having a stem extending through said port and having a deformable head portion normally sealing said port and held against the external surface of said partition by atmospheric pressure; said deformable head portion assuming an altered configuration when the vacuum within said inner chamber is dissipated and atmospheric pressure no longer forcefully urges said head portion against said partition.

Claim 18

The power module of claim 15 in which said closure member includes a transparent or translucent panel engaged by said head portion and through which said head portion may be viewed when said head portion assumes said altered configuration.

Claim 19

A power module for a drug infusion device comprising a casing having a first chamber and a secodn chamber and having a metering flow pasage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; means for connecting said piston to a syringe module for operating said syringe module as said piston advances from extended to retracted positions; said casing having concentric cylindrical inner and outer walls with said first chamber being disposed between said inner and outer walls and said second chamber being disposed within said inner wall; said piston being annular and slidably engaging opposing surfaces of said inner and outer walls; and detachable means temporarily joining said annular piston and casing for preventing rotation of said annular piston within said first chamber until said means is detached; said annular piston having an outer surface portion extending beyond said outer wall; sad means for preventing rotation of said annular piston comrpising a band of tape adhesively and removably engaging both the outer surface of said outer wall and said surface portion of said annular piston.

Claim 20

A power module for a drug infusion device comprising a casing having a first chamber and a secodn chamber and having a metering flow pasage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; means for connecting said piston to a syringe module for operating said syringe module as said piston advances from extended to retracted positions; said casing having concentric cylindrical inner and outer walls with said first chamber being disposed between said inner and outer walls and said second chamber being disposed within said inner wall; said piston being annular and slidably engaging opposing surfaces of said inner and outer walls; and detachable means temporarily joining said annular piston and casing for preventing rotation of said annular piston within said first chamber until said means is detached; said annular piston having an outer surface portion extending beyond said outer wall; sad means for preventing rotation of said annular piston comrpising a band of tape adhesively and removably engaging both the outer surface of said outer wall and said surface portion of said annular piston.

Claim 21

A drug infusion device having a power section and a syringe section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being of constant volume and under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said constant volume second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; and means for operatively connecting said power and syringe sections to that retraction of said piston causes advancement of said syringe plunger.

Claim 22

A drug infusion device having a power section and a syringe section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being of constant volume and under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said constant volume second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; and means for operatively connecting said power and syringe sections to that retraction of said piston causes advancement of said syringe plunger.

Claim 23

The device of claim 18 in which said power and syringe sections constitute separate modules; said means for connecting said sections comprising interfitting portions of said sections.

Claim 24

The device of claim 19 in which said syringe section is provided with a piercable membrane within said barrel adjacent said outlet; and a hollow needle within said barrel having a lumen communicating with said outlet and having a pointed tip for piercing said membrane as said plunger is advanced within said barrel.

Claim 25

The device of claim 18 in which said casing has concentric cylindrical inner and outer walls; said second chamber being disposed within said inner wall and said first chamber being disposed between said inner and outer walls.

Claim 26

The device of claim 21 in which said piston is annular and slidably engages opposing surfaces of said inner and outer walls.

Claim 27

The device of claim 18 in which said viscous fluid undegoes a viscosity change at different temperatures within the operative temperature range of said module; said second chamber under partial vacuum containing a small amount of a volatile fluid having an offsetting change in partial pressures within said operative range and being immiscible in said viscous fluid.

Claim 28

The device fo claim 18 in which said viscous fluid is polyisobutylene.

Claim 29

The device of claim 18 in which said casing has concentric cylindrical inner and outer walls with said first chamber being disposed between said inner and outer walls and said second chamber being disposed within said inner wall; said piston being annular and slidably engaging opposing surfaces of said inner and outer walls; and detachable means temporarily joining said annular piston and casing for preventing rotation of said annular piston within said first chamber until said means is detached.

Claim 30

A drug infusion device having a power section and a syringe section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow passage therebeween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; means for operatively connecting said power and syringe sections so that retraction of said piston causes advancement of said syringe plunger; said power and syringe sections constituting separate modules and said means for connecting said sections comprising interfitting portions of said sections; said interfitting portions including lugs provided by one of said sections and lug-receiving slots provided by the other of said sections.

Claim 31

A drug infusion device having a power section and a syringe section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow passage therebeween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; means for operatively connecting said power and syringe sections so that retraction of said piston causes advancement of said syringe plunger; said power and syringe sections constituting separate modules and said means for connecting said sections comprising interfitting portions of said sections; said interfitting portions including lugs provided by one of said sections and lug-receiving slots provided by the other of said sections.

Claim 32

The device of claim 26 in which said lugs are provided by said syringe barrel at one end thereof and said slots are provided by said piston of said power section.

Claim 33

The device of claim 26 in which at least one of said lugs and piston have ratchet teeth for preventing disengagement following coupling of said sections.

Claim 34

A drug infusion device having a power section and a syring section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; means for operatively connecting said power and syringe sections so that retraction of said piston causes advancement of said syringe plunger; said power and syringe sections constituting separate modules; said means for connecting said sections comprising interfitting portions of said sections; said power unit including a portion of said casing that engages the plunger of said syringe, and advances said plunger a limited distance to discharge a bolus of drug from said barrel, as said sections are connected together.

Claim 35

A drug infusion device having a power section and a syring section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; means for operatively connecting said power and syringe sections so that retraction of said piston causes advancement of said syringe plunger; said power and syringe sections constituting separate modules; said means for connecting said sections comprising interfitting portions of said sections; said power unit including a portion of said casing that engages the plunger of said syringe, and advances said plunger a limited distance to discharge a bolus of drug from said barrel, as said sections are connected together.

Claim 36

A drug infusion device having a power section and a syring section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; means for operatively connecting said power and syringe sections so that retraction of said piston causes advancement of said syringe plunger; said power and syringe sections constituting separate modules; and means for connecting said sections comprising interfitting portions of said sections; said syringe section being provided with a piercable membrane within said barrel adjacent said outlet; and a hollow needle within said barrel having a lumen communicating with said outlet and having a pointed tip for piercing said membrane as said plunger is advanced within said barrel; said power unit including a portion of said casing that engages the plunger of said syringe, and advances said plunger a limited distance to cause piercing of said membrane by a needle and a discharging of a bolus of drug from said barrel, as said sections are conected together.

Claim 37

A drug infusion device having a power section and a syring section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; means for operatively connecting said power and syringe sections so that retraction of said piston causes advancement of said syringe plunger; said power and syringe sections constituting separate modules; and means for connecting said sections comprising interfitting portions of said sections; said syringe section being provided with a piercable membrane within said barrel adjacent said outlet; and a hollow needle within said barrel having a lumen communicating with said outlet and having a pointed tip for piercing said membrane as said plunger is advanced within said barrel; said power unit including a portion of said casing that engages the plunger of said syringe, and advances said plunger a limited distance to cause piercing of said membrane by a needle and a discharging of a bolus of drug from said barrel, as said sections are conected together.

Claim 38

A drug infusion device having a power section and a syringe section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; means for operatively connecting said power and syringe sections so that retraction of said piston causes advancement of said syringe plunger; said casing having concentric inner and outer walls; said second chamber being disposed within said inner wall and said first chamber being disposed between said inner and outer wals; said piston being annular and slidably engaging opposing surfaces of said inner and outer walls; said metering passage comprising an opening in said inner wall; said valve means comprising a valve member movably mounted in said casing for controlling flow through said opening.

Claim 39

A drug infusion device having a power section and a syringe section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; means for operatively connecting said power and syringe sections so that retraction of said piston causes advancement of said syringe plunger; said casing having concentric inner and outer walls; said second chamber being disposed within said inner wall and said first chamber being disposed between said inner and outer wals; said piston being annular and slidably engaging opposing surfaces of said inner and outer walls; said metering passage comprising an opening in said inner wall; said valve means comprising a valve member movably mounted in said casing for controlling flow through said opening.

Claim 40

The device of claim 31 in which said valve means includes a closure member rotatably received in said casing and forming a wall portion of said inner chamber; said closure member having a partition with a port extending therethrough; and vacuum integrity indicating means comprising a resilient member having a deformable head portion normally sealing said port and held against the external surace of said partition by atmospheric pressure; said deformable head portion assuming an altered configuration when the vacuum within said inner chamber is dissipated and atmospheric pressure no longer forcefully urges said head portion against said partition.

Claim 41

The device of claim 32 in which said closure member includes a transparent or translucent panel engaged by said head portion and through which said head portion may be viewed when said head portion assumes said altered configuration.

Claim 42

A drug infusion device having a power section and a syringe section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow paassage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; means for operatively connecting said power and syringe sections so that retraction of said piston causes advancement of said syringe plunger; said casing having concentric inner and outer walls; said second chamber being disposed within said inner wall and said first chamber being disposed between said inner and outer walls; said piston being annular and slidably engaging opposing surfaces of said inner and outer walls; said valve means comprising a closure member rotatably received in said inner chamber and forming an end wall for said chamber; said opening in said inner wall being in the form of an elongated slot extending in the direction of rotation of said closure member.

Claim 43

A drug infusion device having a power section and a syringe section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow paassage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacuum-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; means for operatively connecting said power and syringe sections so that retraction of said piston causes advancement of said syringe plunger; said casing having concentric inner and outer walls; said second chamber being disposed within said inner wall and said first chamber being disposed between said inner and outer walls; said piston being annular and slidably engaging opposing surfaces of said inner and outer walls; said valve means comprising a closure member rotatably received in said inner chamber and forming an end wall for said chamber; said opening in said inner wall being in the form of an elongated slot extending in the direction of rotation of said closure member.

Claim 44

The device of claim 34 in which said closure member also has an elongated slot extending in the direction of, and alignable with, said slot of said inner wall.

Claim 45

A drug infusion device having a power section and a syringe section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacumm-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; means for operatively connecting said power and syringe sections so that retraction of said piston causes advancement of said syringe plunger; said casing having concentric cylindrical inner and outer walls with said first chamber being disposed between said inner and outer walls and said second chamber being disposed within said inner wall; said piston being annular and slidably engaging opposing surfaces of said inner and outer walls; detachable means temporarily joining said annular piston and casing for preventing rotation of said annular piston within said first chamber until said means is detached; said annular piston having an outer surface portion extending beyond said outer wall; said means for preventing rotation of said annular piston comprising a band of tape adhesively and removably engaging both the outer surface of said outer wall and said surface portion of said annular piston.

Claim 46

A drug infusion device having a power section and a syringe section; said power section comprising a casing having a first chamber and a second chamber and having a metering flow passage therebetween; adjustable valve means for opening and closing said passage; a piston slidably received in said casing and constituting a movable wall of said first chamber; said second chamber being under partial vacuum and said first chamber containing a vacumm-stable viscous fluid therein; whereby, as said viscous fluid flows through said passage from said first chamber into said second chamber in response to said vacuum, said piston progressively slides in said casing from an extended position into a retracted position; said syringe section including a barrel for containing a liquid drug to be infused, an outlet for discharge of said drug from said barrel, and a plunger slidably received within said barrel and capable of being advanced within said barrel to displace drug therefrom; means for operatively connecting said power and syringe sections so that retraction of said piston causes advancement of said syringe plunger; said casing having concentric cylindrical inner and outer walls with said first chamber being disposed between said inner and outer walls and said second chamber being disposed within said inner wall; said piston being annular and slidably engaging opposing surfaces of said inner and outer walls; detachable means temporarily joining said annular piston and casing for preventing rotation of said annular piston within said first chamber until said means is detached; said annular piston having an outer surface portion extending beyond said outer wall; said means for preventing rotation of said annular piston comprising a band of tape adhesively and removably engaging both the outer surface of said outer wall and said surface portion of said annular piston.