Stepped check valves

A check valve, comprising:

• an upper housing defining an inlet of the check valve, a lower housing defining an outlet of the check valve, and a cavity formed between the upper housing and lower housing for fluidly connecting the inlet and the outlet, the lower housing comprising a biasing post disposed in a central portion of the cavity;
• and
• a stepped valve member to selectively permit a fluid flow in a first direction and restrict fluid backflow in a second direction opposite to the first direction, the stepped valve member seated in the cavity on the biasing post such that, when a downstream pressure is applied to the stepped valve member, an outer edge of the stepped valve member is configured to deflect toward and engage against a sealing surface of the upper housing to resist fluid communication between the inlet and the cavity.

A method for providing a check valve, the method comprising:

• providing an upper housing defining an inlet of the check valve;
• providing a lower housing defining an outlet of the check valve and a biasing post disposed in a central portion of a cavity formed between the upper housing and lower housing;
• providing a stepped valve member seated in the cavity on the biasing post such that an outer edge of the stepped valve member is resisted from engaging against the upper housing, wherein the stepped valve member permits a fluid flow in a first direction from the inlet toward the outlet, and resists the fluid flow in a second direction from the outlet toward the inlet.