Translate the given Spanish text to English

A valve body (26) is received within the seat (20) and comprises a curved surface (28) and a planar surface (30) that extends across the curved surface (28).

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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Un cuerpo de valvula (26) es recibido dentro del asiento (20) y comprende una superficie curveada (28) y una superficie plana (30) que se extiende a traves de la superficie curveada (28).