Abstract: Hydrostatic test apparatus for pressure testing fire hoses, pressure vessels such as fire extinguishers, or the like, including a small, portable unit having an inlet line for connection to a hose from an ordinary water tap, for example, an outlet line connected to the item to be tested, a pump, a first bypass line between the inlet lines for filling the item being tested, a control valve in the first bypass line which is closed during testing to prevent backflow of test pressure into the water supply, a pressure gauge in the outlet line for reading test pressure, and an adjustable relief valve in a second bypass line between the inlet and outlet lines for setting a predetermined test pressure. Air vents or bleeds allow the apparatus to be completely bled of air before testing to assure accuracy of the test pressure readings. The apparatus operates on very low water volume for safety.

Abstract: Methods of and apparatus for maintaining fluid materials at selected bulk temperatures which employ solar energy as the primary heat source. The methods and apparatus may be used to, for example, protect fluids against freezing and to keep their viscosity from exceeding a predetermined level.