Abstract: A removeable circular lid with a sealant coating on said inner surface, with vacuum release apparatus, has a lid, and a lid cap. The lid has one or more through holes. The lid cap has one or more protrusions, equal to the number of through holes, wherein the protrusions align with the through holes, and protrude through the holes. The lid cap is rotatable relative to the lid, and the through holes are larger than the protrusions, such that when the cap is rotated relative to the lid, rotation is allowed for the play of the protrusions in the through holes. The sealant coating is applied to the lid with the lid cap in a position such that the protrusions are seated at the furthest clockwise position of the through hole when looking from the top allowing for clearance for the sealant to cover the cut edges of the hole.

Abstract: An educational device to measure the strength and deflection of a sample truss comprises a mounting base having opposing posts, an adjustable sliding force plate, a load clip, a pulling means, a force measuring means, and a deflection measuring means. The truss has a longitudinal side and an opposing side with a load point, and a first end and an opposing second end. The truss is laid on the sliding force plate such that the longitudinal side is against the opposing posts, wherein one post is at the first end and one post is at the second end. The load clip is mounted on the sliding force plate, and centered relative to the opposing posts, such that when the truss is placed on the sliding force plate, the load clip is against the truss load point. The pulling means functions to pull the load clip against the truss load point, which in turn pulls the truss first longitudinal side against the opposing posts, causing a load on the truss.

Abstract: This is a kit for demonstrating Archimedes' principle and comprises a tub having an overflow spout, such that when a fluid level reaches the overflow spout, all additional fluid added to the tub will flow out of the overflow spout; and a stable boat sized to float in the tub without touching the sides of the tub. The kit may further comprise a balance beam which can balance on an edge of the tub, wherein one end of the balance beam has an attachment mechanism for attaching a counter weight, and the other end has an attachment mechanism for attaching a sample weight such that when the sample weight attached to this end, and the balance beam is balancing on the too edge of the tub, the sample weight will be submerged in the fluid in the tub. There is also provided a method for using this kit to demonstrate Archimedes' principle both for the buoyancy of a floating body, and the buoyancy for objects that do not float.

Abstract: A sanitary pump station for removing waste from recreational vehicle and pleasure craft waste tanks is provided. A pump station housing encloses a motor driven pump provided with at least a pair of one-way valve arrangements in both inlet and outlets to the pump. A waste hose is connected to the pump inlet and stored on a reel device within the housing. A water hose connected to an external water source is also provided. The water hose is also stored in the housing on a second reel. The respective hoses may be pulled from the housing, selectively, and after use, may be rewound on the reels by a rewind mechanism selectively engageable with drive pulleys associated with the respective reels. A universal adaptor is also provided to enable connection between the waste hose and the termination valve of the waste tank.