Self-sealing container for protecting air sensitive samples
A self-sealing container, used for transferring one or more air sensitive samples between vacuum systems, includes a housing with a cavity that holds the sample(s), and a lid disposed on top of the housing. The lid is configured to interface with the housing to form a seal over the cavity when the lid is closed. At least two flexure systems, each coupled to the housing and the lid, are disposed on opposing sides of the housing. The flexure systems apply forces to the lid that move the lid horizontally and vertically above the housing, into an open position. A pneumatic actuator, movably coupled to the housing and the lid, that is actuated by a change in ambient pressure. When actuated, it applies forces that move the lid horizontally and vertically to the closed position, in opposition to and in excess of the forces applied by the flexure systems.
1. A self-sealing container for use in transferring one or more air sensitive samples into and out of a vacuum system, the container comprising:
a housing comprising a cavity configured to receive the one or more samples;
a lid, disposed on top of the housing, that is configured to interface with the housing to form a seal capable of sealing the one or more samples in the cavity when the lid is in a closed position;
two or more flexure systems, each flexure system coupled to the housing and the lid, one of the flexure systems is disposed on one side of the housing and the other flexure system is disposed on an opposing side of the housing, the flexure systems configured to apply forces to the lid that move the lid horizontally and vertically above the housing, into an open position; and
a pneumatic actuator actuated by a change in ambient pressure, movably coupled to the housing and the lid, that is configured to apply forces to the lid, when the pneumatic actuator is actuated, that move the lid horizontally and vertically from the open position to the closed position, in opposition to and in excess of the forces applied by the flexure systems.
2. The self-sealing container of claim 1 , wherein the pneumatic actuator is positioned at an angle relative to the lid.
3. The self-sealing container of claim 2 , wherein the pneumatic actuator is positioned at a ten (10) degree angle relative to the lid.
4. The self-sealing container of claim 1 , wherein each flexure system includes at least two stages.
5. The self-sealing container of claim 4 , wherein each flexure system is formed from a single piece of material.
6. The self-sealing container of claim 4 , wherein each stage comprises a strip of material coupled to one other stage in series.
7. The self-sealing container of claim 1 , wherein one end of a first stage is attached to the housing and one end of a second stage is attached to the lid.
8. The self-sealing container of claim 1 , wherein each stage of a flexure system includes a strip of material comprising titanium, brass, a steel alloy, or combinations thereof.
9. The self-sealing container of claim 1 , wherein the pneumatic actuator is a double-acting cylinder having a piston movable within the cylinder, the cylinder coupled to the housing and the piston movably coupled to the lid.
10. The self-sealing container of claim 9 , further comprising a valve in one end of the cylinder, wherein the valve is configured to connect to a pump that actuates the piston by drawing air out of the one end to form a vacuum therein.
11. The self-sealing container of claim 9 , wherein the pneumatic actuator is actuated when a difference in the pressure on one side of the piston compared to the pressure on the other side of the piston within the cylinder reaches a predetermined value.
12. The self-sealing container of claim 9 , further comprising coatings on surfaces of the cylinder and the piston that contact one another, to reduce friction.
13. The self-sealing container of claim 1 , wherein the pneumatic actuator is a bellows.
14. The self-sealing container of claim 1 , wherein the pneumatic actuator is expanding foam.
15. The self-sealing container of claim 1 , further comprising a flow resistor coupled to the pneumatic actuator and configured to affect a rate of change in the pressure within the pneumatic actuator in order to delay movement of the lid to the open position by the flexure systems.
16. The self-sealing container of claim 1 , further comprising a square o-ring that is disposed around a perimeter of the cavity and configured to form the seal between the lid and the housing.
17. The self-sealing container of claim 1 , wherein the container includes four flexure systems, each flexure system includes three (3) stages in series, two of the flexure systems are disposed on one side of the housing, and the other two flexure systems are disposed on an opposing side of the housing.
18. The self-sealing container of claim 1 , further comprising electrical contacts disposed in the cavity, the electrical contacts in electrical communication with the one or more samples.
19. The self-sealing container of claim 1 , wherein the housing includes aluminum and an inner surface of the cavity includes an anodized coating.
20. A method of transferring an air-sensitive sample into and out of a vacuum system, the method comprising:
providing a container having a cavity in a housing, the cavity configured to receive a sample, a lid disposed on the housing, the lid having an open position and a closed position and configured to seal the sample in the cavity when the lid is in the closed position and is spring-biased in the open position and a piston assembly
configured with a first side thereof coupled to ambient pressure and a second side thereof coupled to a valved port, wherein the piston assembly
includes a piston coupled to the lid and configured to move the lid to the closed position when net forces on both sides of the piston owing to pressure differences are sufficient to overcome the spring bias and to retain the lid in the closed position;
placing the container in a glove box flooded with inert gas and with the valved port open, whereupon ambient pressure exists on the first and second sides of the piston assembly so that the pressures are approximately equal and the spring-biased lid is in the open position;
placing the sample in the cavity;
coupling a pump to the valved port, running the pump to bring down pressure on the second side of the piston assembly to a desired level of vacuum, and closing the valved port, so that the lid is retained in the closed position;
moving the container into a chamber of the vacuum system;
evacuating the chamber of the vacuum system, whereupon the ambient pressure on the first side of the piston assembly drops to match the vacuum pressure on the second side of the piston assembly and the pressures are approximately equal and the spring-biased lid is in the open position, so that the sample can be analyzed by the vacuum system;
after analyzing the sample, flooding the chamber of the vacuum system with inert gas, whereupon ambient pressure on the first side of the piston assembly is increased and the pressure difference between the first and second sides of the piston assembly is again sufficient to overcome the spring bias and to retain the lid in the closed position; and
removing the sample from the chamber of the vacuum system.
21. A container comprising:
a cavity in a housing, the cavity configured to receive a sample;
a lid disposed on the housing, the lid having an open position and a closed position and configured to seal the sample in the cavity when the lid is in the closed position and is spring-biased in the open position; and
a piston assembly
configured with a first side thereof coupled to ambient pressure and a second side thereof coupled to a valved port, wherein the piston assembly
includes a piston coupled to the lid and configured to move the lid to the closed position when net forces on both sides of the piston owing to pressure differences are sufficient to overcome the spring bias and to retain the lid in the closed position.