This invention relates to liquid dispensers and more particularly comprises a dispenser particularly suitable for mixing and dispensing high density liquids such as barium sulphate and liquids in suspension. A particular application of this dispenser is in X-ray laboratories where barium sulphate is dispensed to patients before undergoing examination. In the following description, the dispenser is described in terms of its use as a barium sulphate dispenser but it will be appreciated that the invention has wider application.
At the present time, barium sulphate is regularly mixed and dispensed from a container by mixing the prescribed amount of barium sulphate with water (usually tap water) and then pouring the mix into a cup for the patient to drink. Because the mixture is warm or at best only slightly cool, the patient is reluctant to drink it because of the taste. Moreover, the mix is not always consistent.
Heretofore, automatic dispensers have been considered unsuitable for this use because of the difficult problems involved in handling the barium sulphate. For example, the barium sulphate is not soluable in water and tends to settle to the bottom of the liquid. Consequently, the liquid must be shaken constantly to avoid the settling action or kept in suspension by a constant paddling. A more acute problem in handling barium sulphate arises from the tendency of the liquid to dry and block the discharge opening of its container. If a valve controls flow through the discharge, the valve must be heavy enough or have biasing means which are sufficiently forceful to cause the valve to close. In addition, the valve must be so constructed that the liquid does not collect in the discharge passge, exposed to the atmosphere, and be permitted to dry there which would very quickly clog the valve.
One important object of this invention is to provide a dispensing valve which will not clog when called upon to dispense such high density liquids as barium sulphate.
Another important object of this invention is to provide a liquid dispenser having a circulator capable of handling heavy liquids that have a density two or more times that of water without a great amount of settling of theinsoluable particles in the mix.
Yet another important object of this invention is to provide a liquid dispenser having cooperating circulation and refrigeration systems capable of maintaining the temperature of heavy liquids in the range of 35.degree. F.
To accomplish these and other objects, the dispenser of this invention includes a bowl having a variable speed paddle-type mixer-circulator and an evaporator coil which together mix and circulate and refrigerate the liquid. The mixer-circulator and evaporator are free of restricted passages so as not to impede the flow of liquid having a specific gravity of two or more. The dispenser also includes a specially designed valve which is vented so as not to allow any liquid to accumulate in the valve after it is closed. As a result, no liquid is trapped in the valve beyond the influence of the circulating system in the bowl.
These and other objects and features of this invention will be better understood and appreciated from the following detailed description of one embodiment thereof, selected for purposes of illustration and shown in the accompanying drawing.