A sleeve for pinch valves is an innovative form, consisting of a completely flexible thin wall with a basic construction of two thin sheets of plastic, formed, shaped and bonded together. It is a design that does not contain stiffening or rigid additives. A flexible casing is collapsed by external pressure being exerted, which produces functions related to applications including pumping, metering and mixing. This type of valve and the action produced by it takes the form of a pinch valve.
A membrane or sleeve reside inside the casing of the valve and is protected by the valve casing. In the case of a manual operation when a handle on the valve is operated, the sleeve for pinch valves is 'pinched' closed. A flow of material or fluid may require a fine degree of control, for which this type of valve and its sleeve is particularly suitable. An application involving the processing of abrasive slurry is also handled efficiently and users benefit by being able to replace the sleeve on site due to wear. An advantage over rigid wall systems is provided by the manufacture and usage of a micro-fluidics system, developed from a sleeve for pinch valve form. It is a benefit relative to a decrease in operating costs and fewer chemical issues, particularly when related to compatibility in chemical and biological assays. The monolithic structure in this form with external actuation, it has been claimed, produces a level of accuracy of over 5% during valve action, in pumping, mixing and the metering of fluids.
This type of sleeve for pinch valve is compact and compatible with wafer-level integration and if necessary, pneumatic cylinders may be used to produce increased actuation displacement, as opposed to a membrane actuator. The actuation by pneumatic methods could also be on an isolated and would include sleeve methods, with actuators using pneumatic cylinders. It is usual for plastic fluidics systems to utilize devices that are constructed and have related dimensions to those produced in a silicone form. Within the field of valves, a sleeve for pinch valve is compared with those valves featuring flexible sleeve and is seated against a rigid formed wall. A further aspect is the many types of pumps that operate on a vibration basis, of a sleeve against fluids restrained by a rigid wall.
A sample fluid can be completely isolated from actuators by the utilization of this thin walled, flexible valve form of a membrane for pinch valve. This is an advantage in that the actuators can reside in a form that is not compatible with the processed fluids. It is also a model of valve that creates the potential for the use of thermal actuators. This variety of actuator usually requires designated thermal management to enable the reduction of power consumption and a response. In addition to the external actuation, is the added possibility that the systems of the future will incorporate external optical sensors, which will also be isolated from the processed fluids.