Various embodiments of exhaust valves are described. In an example, an exhaust valve assembly includes a valve body having a cylinder, a piston disposed within the cylinder, and a sealing material disposed within a trough at the bottom of the cylinder. The selection of the sealing material may be based on an operational temperature that is above a melting point of the sealing material.
1. A method, comprising:
placing a raw material in a container comprising an opening;
removably coupling the opening in the container with an exhaust valve assembly comprising:
a valve body comprising a cylinder and a trough disposed within the cylinder along a bottom portion of the valve body;
a piston slideably engaged within the cylinder, wherein at least a portion of the piston is configured to reside within the trough when the piston is in a resting position; and
a piston sealing material disposed within the trough, wherein the piston sealing material has a melting point below a first operational temperature;
heating the container holding the raw material to generate an exhaust gas, wherein the exhaust gas passes through the opening, elevates the piston, and melts the piston sealing material; and
allowing the container to cool to cease generation of exhaust gas, wherein a decrease in exhaust gas pressure allows the piston to return to the resting position, and wherein the piston sealing material solidifies as the container cools, thereby creating an air-tight seal.
2. The method of claim 1 , further comprising removing the exhaust valve assembly from the opening of the container.
3. The method of claim 1 , wherein the raw material is lithium iron phosphate.
4. The method of claim 3 , wherein the first operational temperature is based on an exhaust gas temperature for a lithium iron phosphate pre-sintering process.
5. The method of claim 1 , wherein the first operational temperature is between 200° C. and 400° C.
6. The method of claim 1 , wherein the first operational temperature is between 200° C. and 500° C.
7. The method of claim 1 , wherein the first operational temperature is between 300° C. and 400° C.
8. The method of claim 1 , wherein the first operational temperature is between 300° C. and 500° C.
9. The method of claim 1 , wherein the exhaust valve assembly is removably coupled to the opening of the container by screwing a threaded surface on an outer periphery of the valve body into a receptive threaded surface disposed along an inner periphery of the opening of the container, and wherein a thread sealing material is compressed between the threaded surfaces of the valve body and the opening of the container.
10. The method of claim 9 , wherein the thread sealing material comprises a powdery mixed metallic material.
11. The method of claim 10 , further comprising forming the thread sealing material into a shaped wire band.
12. The method of claim 1 , further comprising positioning a retention plate within the valve body above the piston.
13. The method of claim 1 , wherein the piston comprises a high temperature resistant ceramic material.
14. The method of claim 1 , wherein the valve body further comprises a spring configured to exert a downward force on the piston.