The present disclosure generally relates to a system for managing bulk liquids and/or bulk solids for in-vitro diagnostics.
In-vitro diagnostic assays are nowadays typically automated. A large number of diagnostic instruments are available, which may conduct different types of assays. Depending on throughput, these diagnostic instruments may consume large amounts of bulk supply liquids such as wash liquids, system liquids and reagents as well as a large amount of bulk supply solids, such as reaction vessels and disposable pipetting tips required for processing samples. On the other hand, the same diagnostic instruments may generate large amounts of bulk waste liquids such as samples, reagents, wash and system liquids, mixtures thereof, as well as bulk waste solids such as sample vessels, reaction vessels, reagent vessels, disposable tips used for processing samples. These bulk waste liquids and solids generate significant disposal problems due to possible contamination with various infectious diseases. As a result, rules and regulations for the handling and disposal of waste have been imposed by various governmental and regulatory agencies, requiring the use of automated controls to protect from exposure.
Various systems have been implemented in the field of in-vitro diagnostics for managing bulk liquids and bulk solids.
A technical problem encountered when automatically managing bulk liquids and/or bulk solids is the fill volume detection, that is the detection of the amount of bulk liquid or solid in a bulk container in order to determine at least when it is empty or nearly empty in the case of a bulk supply container and when it is full or nearly full in the case of a bulk waste container.
Commonly used sensors for fill volume detection are normally suitable only for specific applications, for example, only for bulk liquids. For example, several liquid level detectors are known. Some of these are invasive, requiring, for example, a probe such as a floating or immersed assembly, for example, an electrode. Invasive methods present major disadvantages for diagnostic applications. Invasive sensors are expensive, are dependent on the characteristics of the liquid such as chemical composition, conductivity, presence of foam, viscosity and temperature. They are also prone to chemical deposition and contamination and require cleaning and maintenance.
Other types of liquid level detectors, which are non-invasive, are also known, like for example acoustic or optical detectors. These detectors, however, depending on container type and material, may be difficult to position and to handle, they are more expensive, and may present issues with long-term stability and space requirements. The characteristics of the liquid such as the presence of foam may also affect the performance.
Gravimetric detectors to measure the weight of bulk containers are also known. These are however expensive, complex, large in size whereas the space in the instrument is typically limited, difficult to position and not reliable as they may be influenced by other elements coupled to the bulk containers.
Pressure detectors such as strain gauge detectors are also known. They suffer however from long-term stability and environmental factors such as humidity and temperature.
Also, both invasive and-non invasive detectors have a low applicability for continuous loading/unloading of bulk containers, i.e., during operation of the instrument.
Therefore, there is a need for a system for managing bulk liquids and/or bulk solids, which is cheap, compact, more accurate, more robust, more reproducible, more long-term stable, and less influenced by environmental and handling factors and that it is applicable for both bulk supply liquids and bulk supply solids, as well as for both bulk waste liquids and bulk waste solids so that the system is independent from the characteristics of a bulk liquid such as chemical composition, conductivity, presence of foam, viscosity and temperature.