Simsite is a graphite-fibre reinforced composite material manufactured by the Sims Pump Valve Company. Simsite is a heavy duty structural composite laminate material which must be machined to create such parts as impellers and casing rings. Specifically, it is a graphite combination-fibre reinforced composite material with phenolic resin. Depending on the application, the fibres are interwoven in a bi-directional or tri-directional weave. The reinforcing fibres are all continuous for high strength. The Simsite composite consists of equal amounts of structural fibres and resin for high physical properties and a wide range of chemical resistance.
The physical characteristics of the Simsite composite can be changed to accommodate the required structural strength and service of the part being manufactured. For example, the tensile strength of Simsite might be 20,000 psi - 120,000 psi depending on the application.
Simsite will not corrode in salt water or in brackish water. Simsite is corrosion resistant to most salts, all hydrocarbon fuels and solvents as well as most acids and alkaline solutions.
CORROSION RESISTANCE -- Simsite will not corrode in salt water or brackish water. It is also excellent with most acids, and is not damaged by gasoline, oil or refinery products.
HIGH MECHANICAL STRENGTH -- Simsite can be used to replace many metal products which are subject to corrosion and erosion.
EXCELLENT MOISTURE RESISTANCE -- The Simsite composite is virtually unaffected by water or salt water and therefore is perfect for the replacement of pump parts and bearings. Simsite bearings are not very hygroscopic, and therefore will not become soft and spongy giving way to radial movement.
LIGHT WEIGHT -- The high strength to weight ratio makes Simsite the correct choice for impellers. By reducing the weight of the impellers you are reducing static deflection and are changing the length to diameter characteristics of the shaft. The light weight becomes a safety factor when assembling or disassembling a Simsite part.
PROTECTS METAL SHAFTS -- The use of Simsite as a sleeve, impeller or bearing will protect the shaft from corrosion and wear. Because Simsite is softer than metal it will not score the surface of the shaft. Should abrasive particles enter the system they will sink below the surface of the Simsite and will not scratch the surface.
LOW COEFFICIENT OF FRICTION -- Simsite has an extremely low coefficient of friction because it has loose graphite embedded in the resin which acts as a lubricant. When lubricated by water, it is ideal for use as guide bearings and stern tube bearings.
REDUCES NOISE AND VIBRATION -- Simsite absorbs noise and vibrations, and cushions shock waves passing through it. The reduction of noise becomes an important safety factor on rotating equipment.
Simsite is an inert material and therefore will not conduct or contribute to electrolysis. The graphite in Simsite is non conductive. By retrofitting inert composite materials into your pump you actually reduce the electrolysis in the pump. The more Simsite you put in your pump the lower the electrolysis. If the pump is 100% Simsite or coated with Simsite Epoxy Coating and fitted with Simsite Internals, then electrolysis will not be present in the pump at all.
For most of our product lines we are using a Hybrid Phenolic-Epoxy Thermosetting Resin Matrix which we blend ourselves. This resin exhibits superior mechanical property qualities as well as good chemical resistance. We have also use Polyimide, and Melamine Resins for some of our special grades of structural composite.
We use continuously, interwoven graphite fibres, glass fibres, and synthetic fibres. The fibres are always continuous, and are interwoven in a tri-dimensional weave for higher strength applications such as impellers.
Are the mechanical properties directional in composites?
One of the big advantages of composites is that the required mechanical properties can be engineered and designed into the finished product.
Since composites are not homogeneous like metallics, mechanical properties are directional. Most composites are moulded and use chopped or cut fibres (filaments). These composites are referred to as Anisotropic (Non uniform mechanical properties). These composites have 36 independent variables.
Simsite composites however use continuous fibres (interwoven) and by definition are structural. Simsite composites are referred to as Balanced Orthotropic and have only 5 independent variables. Metallics have 3 independent variables.
Does water or liquid absorption affect the properties of Simsite composites?
No. The only time a liquid would affect the properties of a structural composite would be if the liquid was a chemical that was not compatible with the matrix and was attacking (destroying) the resin.
As a matter of fact, the liquid absorption (although it is minimal) actually helps the performance of the Simsite Impellers and Casing Rings because it closes the clearance between the rings and the impeller which reduces losses and increases performance and efficiency.
What are the largest Simsite parts produced to date?
The largest Simsite Impeller is 1270mm (50") in diameter located at the Department of Water for New York City. The largest Simsite Casing Rings are 1524mm (60") in Diameter located at Long Island Lighting Company. The largest custom Simsite Ring is 2134mm (84") in Diameter located in Germany. The largest pump is 12.2m (40 feet) long and 915mm (3 feet) in diameter located at Potomac Electric Power Company.
