Patent ID: 8491272

Claim:
A pumping-out apparatus, comprising: a pump; a follow plate that is placed on a fluid surface of a stored fluid stored in a container, a suction port of the pump being attached to an attachment hole of the follow plate, and the stored fluid being able to be pumped up from the suction port and discharged by the pump; a post on which the pump is fixedly provided; a lifted and lowered portion capable of holding the container and provided so as to be able to be lifted and lowered along the post; and a spring, one end of which is coupled to the lifted and lowered portion, and which biases the lifted and lowered portion in an upward direction to cause the fluid surface of the stored fluid in the container to press the follow plate, and wherein a lifting and lowering handle is operatively coupled to the lifted and lowered portion to raise and lower the lifted and lowered portion, wherein the spring is set such that when the stored fluid in the container is pumped up by the pump and a weight of the stored fluid in the container decreases, the container is lifted solely by a biasing force of the spring, and the fluid surface of the stored fluid is caused to press the follow plate by a substantially constant predetermined force; and the spring is a tension spring, the lifted and lowered portion is hung by the spring, and an upper end of the spring is lifted and lowered by the lifting and lowering operation portion, wherein the spring constant k of the spring is calculated according to the formula: k=γ×D; where γ=specific weight of the stored fluid, and where D=cross-sectional area of the container; and wherein the lifted and lowered portion may be lifted and/or lowered via the handle to selectively increase or decrease the biasing force exerted by the spring and the resultant substantially constant predetermined force exerted by the fluid surface on the follow plate; and wherein the follow plate and fluid surface are maintained at substantially the same height while the lifted and lowered portion is lifted as the pump pumps the stored fluid out of the container, and the weight of the container decreases, causing the container to be lifted by the spring, while maintaining the substantially constant predetermined force on the follow plate.