Methods for restricting backflow of solids in a pump assembly

A system comprising:

• a feed injector;
• and
• a pump assembly coupled to said feed injector, said pump assembly comprising:
• a rotating component;
• a stationary component coupled to said rotating component such that said stationary component substantially circumscribes at least a portion of said rotating component;
• a high pressure outlet extending at least partially through each of said rotating component and said stationary component;
• an inlet positioned a predefined distance from said high pressure outlet, said inlet extends at least partially through each of said rotating component and said stationary component, a solid fuel flow is channeled from said inlet to said high pressure outlet as said rotating component rotates;
• and
• a flow control member coupled to said rotating and said stationary components in a first predefined position, wherein said flow control member is selectively moveable from the first predefined position to a second predefined position to form a seal within said pump assembly such that the solid fuel flow and a fluid flow are substantially restricted from being channeled back into said inlet.

A method of restricting a backflow of solids using a pump assembly, said method comprising:

• coupling the pump assembly to a feed injector, wherein the pump assembly includes a stationary component coupled to a rotating component such that the stationary component substantially circumscribes at least a portion of the rotating component;
• channeling a solid fuel flow from a solid feed source to an inlet that extends at least partially through each of the rotating and stationary components;
• rotating the rotating portion such that the solid fuel flow is channeled from the inlet to a high pressure outlet positioned a predefined distance from the inlet, wherein the high pressure outlet extends at least partially through each of the rotating and stationary components;
• and
• imparting a motion to a flow control member coupled to the rotating and stationary components at a first predefined position to selectively move the flow control member from the first predefined position to a second predefined position to form a seal within the pump assembly such that the solid fuel flow and a fluid flow are substantially restricted from being channeled back into the inlet.