Abstract: A shell-and-tube heat exchanger includes a shell which defines a passageway extending from a first end to a second end of the shell, a resilient tubesheet having an outer peripheral surface in sealing engagement with an inner peripheral surface of said shell proximate the first end of the shell, the resilient tubesheet supporting a plurality of tubes which extend within the passageway toward the second end, a cap which closes the first end of the shell in a manner in which a space exists between the cap and the resilient tubesheet, and a seal which seals a portion of the inner peripheral surface of the shell between the resilient tubesheet and the first end from the space between the cap and the resilient tubesheet.

Abstract: A shell-and-tube heat exchanger includes a shell which defines a passageway extending from a first end to a second end of the shell, a resilient tubesheet having an outer peripheral surface in sealing engagement with an inner peripheral surface of said shell proximate the first end of the shell, the resilient tubesheet supporting a plurality of tubes which extend within the passageway toward the second end, a cap which closes the first end of the shell in a manner in which a space exists between the cap and the resilient tubesheet, and a seal which seals a portion of the inner peripheral surface of the shell between the resilient tubesheet and the first end from the space between the cap and the resilient tubesheet.

Abstract: A gas piston retrofit assembly is provided for a firearm having a bolt assembly mounted within a receiver, a barrel extending forward from the receiver, and a front sight block mounted on the barrel. The retrofit assembly includes a gas tube extending into the front sight block fluidly connected with the barrel, a piston cylinder having an arcuate-shaped piston chamber fluidly connected to the gas tube, a piston including an arcuate-shaped piston head extending forward from a piston body and telescopically received in the piston chamber, and including a piston rod extending rearward from the piston body and dimensioned and configured to extend into the receiver for engaging with a bolt assembly within the receiver. Upon firing a round of ammunition, pressurized gas within the barrel enters the piston chamber to move the piston rearward, for cycling the bolt assembly. A method of using the same is also disclosed.

Abstract: A gas piston retrofit assembly is provided for a firearm having a bolt assembly mounted within a receiver, a barrel extending forward from the receiver, and a front sight block mounted on the barrel. The retrofit assembly includes a gas tube extending into the front sight block fluidly connected with the barrel, a piston cylinder having an arcuate-shaped piston chamber fluidly connected to the gas tube, a piston including an arcuate-shaped piston head extending forward from a piston body and telescopically received in the piston chamber, and including a piston rod extending rearward from the piston body and dimensioned and configured to extend into the receiver for engaging with a bolt assembly within the receiver. Upon firing a round of ammunition, pressurized gas within the barrel enters the piston chamber to move the piston rearward, for cycling the bolt assembly. A method of using the same is also disclosed.