Load receiver devices according to the present invention are used primarily for the determination of the density of solid bodies. During the density determination, the solid body is held in a surrounding fluid which is inside a container that is not coupled to the weighing cell of the balance. The density determination can be performed with solid bodies that float as well as bodies that sink in the fluid. In the case of bodies that float, the density of the body is lower that the density of the surrounding fluid. In the case of bodies that sink, the density of the body is higher that the density of the surrounding fluid. In order to hold the solid bodies in the surrounding fluid, a load receiver device is needed.
A load receiver device for solid bodies that sink in the surrounding fluid belongs to the known state of the art. This load receiver device has a receiver module with a concavity. The depth of the concavity is oriented in the direction of gravity. A solid body that sinks in the surrounding fluid can be seated in this concavity and thereby be held in place in the fluid. This receiver module is not suitable for determining the density of bodies that float on the fluid, as the floating body will rise to the surface of the fluid. Therefore, an additional load receiver device is needed for the density determination of solid bodies that float in the test fluid. This load receiver device, which likewise belongs to the state of the art, has a receiver module with a concavity, wherein the depth of the concavity is oriented against the direction of gravity. The floating solid body is placed below the receiver module. The force of buoyancy acts on the floating body and pushes the latter from below into the concavity, whereby the body is held in place in the fluid.
These state-of-the-art load receiver devices have the disadvantage that different load receiver devices are required to determine the density of floating and sinking solid bodies, respectively.
This drawback has been eliminated by the load receiver device disclosed in U.S. Pat. No. 6,561,025 B2. This load receiver device includes a rigid flat grid which, in the density determination process, is positioned at a right angle to the direction of gravity. For the density determination of a body that sinks, the body is set on the grid. Then the load receiver device with the body on the grid is submerged in the fluid. The force of gravity acting on the body pushes the latter down against the grid, whereby the body is held in place in the surrounding fluid. For the density determination of a floating solid body, the body is likewise placed on the grid. To prevent the body from rising to the surface of the fluid, a buoyancy constraint is put over the body. The buoyancy constraint is configured so that the constraint and the grid together form a hollow enclosure in which the solid body is held in place during the density determination. To perform the density determination on the floating body, the load receiver device and the solid body, which is enclosed between the grid and the buoyancy constraint, are submerged in the fluid. Due to the buoyant force acting on it, the solid body is pushed against the buoyancy constraint and held in place in the fluid. The gravity force acting on the buoyancy constraint must be greater than the buoyant force acting on the solid body. This load receiver device has the disadvantage that an additional part, specifically a buoyancy constraint, is required for the density determination of solid bodies that float.
This disadvantage is circumvented in the load receiver device that is disclosed in U.S. Pat. No. 7,296,466 B2. The load receiver device as disclosed in this reference has a metallic tube with two ends and a flat bottom plate. In the process of a density determination, the axis of the tube is oriented in the direction of gravity. The bottom plate is held captive inside the tube with the freedom to move in the direction of gravity. When performing density determinations on solid bodies that sink in the fluid, the body is set on the bottom plate. Due to the gravity force acting on the body the bottom plate is pushed downwards. A first stop prevents the bottom plate from sliding out of the lower end of the tube. To determine the density of solid bodies that float, the body is placed below the bottom plate. Due to the gravity force acting on the body during the density determination the bottom plate is pushed in the upward direction. A second stop prevents the bottom plate from sliding out of the upper end of the tube. For the density determination of floating solid bodies, the buoyant force acting on the body needs to be strong enough to push the bottom plate upward against the force of gravity. If the density of the solid body is similar to the density of the fluid, the problem arises that the body cannot be reliably held in place in the fluid.
It is therefore an object of the present invention to provide a load receiver device that can be reliably used for the density determination of solid bodies with densities of any magnitude.
The load receiver device is particularly useful in determining the density of solid bodies having a density similar to that of the surrounding fluid.