Tanker pump
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Marketed by George Meller, a Blackmer sliding-vane positivedisplacement tanker pump of stainless steel is made by Stainless Steel Pumps for handling oil and chemical products and foods. It is known as the Model STNP3 and the maker claims that the design is such that galling and seizing of metal-to-metal surfaces is eliminated.
The main wearing parts of the pump are non-metallic sliding vanes of composite construction. To prevent galling of the rotor and heads, a replaceable carbon disc is inset into each pump head which improves the pump's ability to withstand periods of dry-running at the end of each unloading and cleaning operation.
In two mounting positions, the STNP3 pump is selfdraining. Its internal cavities have been designed to assure unobstructed draining flow and this makes flushing and cleaning procedures easier and more effective. When the pump is mounted with the intake port at the top, all liquid within the pump flows downward and out of the discharge port or drain plug near the port if hose couplings prevent complete draining. If the pump is mounted with the discharge port at the top draining is through the intake port. There are no recesses, ledges or pockets to trap and retain the liquid.
The pump maintains its close internal clearances because the vanes automatically self-adjust for wear. As its tip wears, each vane moves farther out of its rotor slot to give the same close contact with the pump cylinder as a new vane.
Pump delivery at 50 psi is 260 gal /min at 640 rpm and at the lower end of the scale, 120 gal /min at 300 rpm. Corresponding horsepower requirements are 9.4 hp and 3 hp respectively. Its maximum differential pressure is 150 psi, while its maximum liquid temperature is 250 deg C.
Marketed by: George Meller Ltd, 26 Hallam Street, London W1.