FREQUENTLY ASKED QUESTIONS ABOUT SIMSITE®
1.) WHAT IS SIMSITE?
Simsite is a graphite-fiber 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-fiber reinforced composite material
with phenolic resin. Depending on the application, the fibers are interwoven in a bi-directional or tridirectional weave. The reinforcing fibers are all continuous for high strength. The Simsite composite
consists of equal amounts of structural fibers 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.
2.) WHAT ARE A FEW OF THE MANY USES OF SIMSITE?
IMPELLERS LIQUID PISTON RINGS
CASING RINGS PUMP VALVE DISCS
WEAR RINGS GEARS
GUIDE BEARINGS PULLEYS
PUMP CASINGS HEAT EXCHANGER COVERS
POWER ENDS-ANSI PUMPS TUBE SHEETS
STERN TUBE BEARINGS VIBRATION BLOCKS
RUDDER BEARINGS CHECK VALVES
EXHAUST GAS FANS ROLLER WHEELS
ROTOR VANES WEAR PLATES
STRAINER BOXES CONDENSER HEAD COVERS
COMPRESSOR RINGS BUTTERFLY VALVES
3.) HOW CORROSION RESISTANT IS SIMSITE?
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.
4.) WHAT ARE THE SPECIAL CHARACTERISTICS OF SIMSITE?
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.
5.) WHAT EFFECT WILL SIMSITE HAVE ON ELECTROLYSIS?
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.
6.) What is the resin system used in Simsite®?
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.
7.) What types of filaments are used in Simsite®?
We use continuously, interwoven graphite fibers, glass fibers, and synthetic fibers. The fibers are always
continuous, and are interwoven in a tri-dimensional weave for higher strength applications such as
impellers.
8). 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 molded and use chopped or cut fibers (filaments). These composites are referred to as
Ansitrophic (Non uniform mechanical properties). These composites have 36 independent variables.
Simsite® composites however use continuous fibers (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.
Material & Coordinate System 3Dimensional
Number of Nonzero
Coefficients
Number of Independent
Coefficients
Anisotropic (Most Composites)
36
21
Specially Orthotropic -- (Structural
Composites)
12
9
Balanced Orthotropic -- SIMSITE®
Structural Composites
12
5
Isotropic -- Metallics
12
2
9). 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.
10). What is the maximum thickness of a Simsite® Structural Composite?
The maximum thickness of a Simsite® composite is 48 inches high. 50" wide X 100" long X 36" high.
11). What coating can be used on the Simsite® Impellers and why?
Simsite® Impellers are not coated. They can however be coated with a Sims Epoxy or a Sims Ceramic
coating to enhance erosion or chemical resistance.
12). What are the largest Simsite® parts produced to date?
The largest Simsite® Impeller is 50" in diameter located at the Department of Water for New York City. The
largest Simsite® Casing Rings are 60" in Diameter located at Long Island Lighting Company. The largest
custom Simsite® Ring is 84" in Diameter located in Germany. The largest pump is 40 feet long and 3 feet in
diameter located at Potomac Electric Power Company.
13). What is the highest temperature application for Simsite®?
The highest temperature for our standard grades of Simsite is 300 degrees F. Our high temperature
composite is good up to 400 degrees F. It is possible to make structural composites for higher temperatures;
however, it gets very expensive.
14). What is the highest horsepower impeller produced to date?
The highest horsepower impellers produced to date are 2000 BHP circulators.
15.) WHY SHOULD I USE SIMSITE IMPELLERS IN ALL MY PUMPS?
Simsite impellers are hydraulically and mechanically superior to other impellers because they are 100%
machined on the outside and inside. Simsite impellers are hydraulically superior to cast metal impellers
because they are free from casting imperfections and have a much lower coefficient of friction.
Simsite impellers are designed to operate at maximum efficiency. The hydraulic design of each impeller is
checked against performance data to insure proper operation of the pump. Should a engineering
modification be required, the design of impeller can easily be changed to provide the customer with the best
possible design for his specific application. Simsite impeller vanes are machined to maximize efficiency and
provide the customer with the best possible vane shape for his particular service.
Simsite impellers are mechanically superior to cast metal impellers because they are light weight which
reduces the static deflection of the shaft and because they are machined as opposed to being cast. Simsite
impellers are approximately 1/6 the weight of bronze and stainless impellers. By reducing the mass of the
impeller, you permanently alter rotor dynamics. When you reduce the weight of the impeller, you reduce
shaft deflection which in turn reduces the radial forces in the pump. The result is that the entire rotating
element lasts much longer.
16.) WHY SHOULD I USE SIMSITE CASING RINGS AND WEAR RINGS IN ALL MY PUMPS?
Simsite casing rings seal very tightly into the casing ring landing areas. When the composite becomes
immersed in the fluid it is pumping, it swells slightly, forming an excellent seal against the metal casing. This
prevents the "wash out" of the landing areas that is the most common problem with pump maintenance.
Also, Simsite Casing Rings and wear rings will not seize or gall; therefore, a tighter clearance can be
maintained which reduces leakage though the rings and increases efficiency.
17) HOW DO I SET THE CLEARANCE BETWEEN THE CASING RINGS AND THE WEAR
RINGS?
The clearances are set at the factory and Simsite impellers and casing rings are sold as a set whenever
possible. The clearances between the impeller wear rings and the casing rings are already calculated when
you purchase the rings and includes a clearance for swell and thermal expansion. However, if the customer
wishes to machine his own rings, Simsite rings may be purchased undersize and oversize and the factory
will tag the rings with the correct clearance.
18.) WHY SHOULD THE CUSTOMER USE SIMSITE GUIDE BEARINGS WHENEVER
POSSIBLE?
Simsite guide bearings will not corrode like bronze bushings. As the bronze bushings corrode and wear,
they allow radial movement of the rotating element which causes premature failure of the wear rings and
casing rings. In extreme cases, this radial movement can cause a shaft to break. Simsite bearings also have
a lower coefficient of friction because of the composition of the material and because of the loose graphite
that is embedded in the resin. The Simsite bearing not only protects the shaft but extends its life.
19.) ARE SIMSITE PARTS SELF-LUBRICATING?
Yes, Simsite parts have loose graphite embedded in the resin system as well as structural graphite. This
loose graphite is an outstanding lubricant and will permit a certain amount of dry running. We have had
situations where the coolant was accidentally shut off to the Simsite composite guide bearings and the pump
did not fail. If, however; the coolant is not restored to the Simsite guide bearings, heat will build up and when
the temperature exceeds 500 deg F the bearings will start to "char". Although the Simsite bearings will not
melt or catastrophically fail like other bearings, the clearances will eventually open up in a dry operating
condition until there is no more wall thickness available.
20.) CAN SIMSITE IMPELLERS BE REPAIRED?
Yes, Simsite impellers can be repaired if the damage is not too extensive. This is a big selling feature. The
product can be sent back for repair and overhaul. When a customer uses Simsite he substantially improves
the time between overhauls. When you take into consideration the fact that the impeller can be repaired, then
the customer's operating costs are lowered even more. All repairs to Simsite parts should be performed at
the factory.
21.) I ALREADY HAVE BRONZE IMPELLERS AND RINGS IN MY PUMPS -- SHOULDN'T I USE
THEM UP FIRST?
No. Bronze impellers and rings in a salt water environment will contribute to the electrolysis inside the pump
and you will jeopardize the life of your pump casing. If you replace the existing bronze impellers and rings
with Simsite, you are replacing metal with an inert material and therefore you are reducing the amount of
electrolysis in the pump. The bronze impellers and rings should be removed and used only as spares. In
addition, as bronze impellers corrode they go into an imbalance situation which will cause premature wear
on all other rotating parts.
22.) IF THE WEAR RINGS SWELL SLIGHTLY, HOW DO YOU ACHIEVE THE CORRECT FIT
FROM THE CASING RINGS TO THE IMPELLER WEAR RINGS?
All composites swell and are subject to thermal expansion. Simsite swells but very minimally. To
compensate for this, the impeller is sold with the casing rings as a unit whenever possible. The clearances
between the impeller wear rings and the casing rings are calculated and set at the factory. Unlike metallic
rings which must maintain a certain clearance, Simsite rings will not seize and gall. Simsite rings are self
lubricating and can endure a certain amount of dry running. If the clearances are accidentally set too close
they will "wear in" with a smooth concentric pattern between the rings rather than seize or gall.
23.) WHY ARE SIMSITE IMPELLERS SUPERIOR TO METAL IMPELLERS?
Simsite impellers are hydraulically and mechanically superior to metal impellers. They are hydraulically
superior because they are machined as opposed to being cast and therefore are not subject to casting
imperfections. Even an investment casting can only hold about .015 accuracy. Simsite impeller vanes can
easily be modified to maximize efficiencies and provide the customer with the best vane shape for his
particular service. Simsite impellers are mechanically superior because they are light weight which reduces
static deflection of the shaft and will therefore reduce radial forces in the pump. Also, Simsite impellers will
not corrode in a salt water or brackish water environment. Simsite impellers are machined from a solid block
and because they are machined from a center point they do not have the balance problems that a casting
would have. When the customer receives a Simsite impeller it is balanced and remains balanced even after
years of service.
24.) WHY SHOULDN'T I PURCHASE INEXPENSIVE "BOOTLEG" METAL IMPELLERS?
Most companies who sell "bootleg" impellers rough cast them or have metal impellers cast for them based
upon a sample that is sent to them. The sample may or may not be accurate and most of these companies
have little or no knowledge of hydraulics and have no way of checking the impeller for performance or
efficiency. They often will follow the cheapest route which can mean disaster for the end user. Sometimes
patterns which are close in design are substituted to save money in pattern costs and the result is the
customer ends up with an impeller which has an incorrect performance. This can cause terrible problems
such as recirculation damage, cavitation, radial reaction and vane tip frequency problems.
Often, cheaper grades of bronze or stainless steel are substituted to save money. The net result of this is
that the impellers or rings wear out very quickly and the "customer" ends up paying more in the end,
because his operating time is substantially reduced with an inferior product.
25.) WHY IS SIMSITE A STRUCTURAL COMPOSITE AND HOW DOES IT DIFFER FROM OTHER
COMPOSITES ON THE MARKET?
Almost all other pump parts manufactured from other composites are either cast or compression molded.
Other manufacturers use chopped up fibers as reinforcement. When you use chopped up fibers to make
parts, you do not have control over the displacement of the reinforcement on complex shapes such as
impellers and you are limited in structural strength.
Sims does not cast or mold the parts it manufactures. Simsite is a structural composite laminate utilizing a
continuous weave graphite carbon fiber reinforcement with phenolic or epoxy resin. All of the pieces are
machined from a structural block of Simsite material. We do not chop any of our reinforcement. Rather, the
reinforcement is interwoven with a certain weave per cubic inch. The amount of weave per cubic inch, the
thickness of the carbon fiber, the type of weave, and the amount of resin per cubic inch determines the
structural strength of the Simsite material. For maximum strength, Simsite utilizes a fiber reinforcement in
three dimensions x, y, and z. Therefore, the Simsite composite can achieve tremendous strength and
integrity.
26.) I HAVE A PUMP WHICH IS ALWAYS A PROBLEM -- CAN SIMSITE HELP?
Yes. If you have a pump which is always giving you a problem, Sims can analyze the problem and in most
cases can redesign the impeller or other rotating parts involved to alleviate the situation. Since Simsite is
machined, costly pattern charges are not involved.
27.) SHOULD I USE SIMSITE FOR SALT WATER APPLICATIONS ONLY?
No. Although the use of Simsite impellers is extremely important in salt water applications because it does
not corrode, it is just as important in fresh water applications. Because Simsite impellers are light weight and
completely machined, they do not have the balance problems that cast metal impellers will have. It is the
imbalance problem that leads to premature wear for the complete rotating element.
28.) DOES SIMSITE® HAVE NOISE ABSORBING CHARACTERISTICS?
Since Simsite is not metallic, it does not reflect noise or vibrations the same way a metallic piece would.
Simsite has noise absorbing characteristics in that it absorbs a percentage of the noise and vibrations as
opposed to reflecting them. Simsite material has been used as a noise barrier to reduce the effects of noise
and vibrations.
Simsite impellers run more smoothly and quietly than metallic impellers primarily because they operate at a
slightly higher efficiency. Simsite impellers do not have casting imperfections, hydraulic or mechanical
balance problems, and they have fewer hydraulic losses.
29.) HOW HARD IS THE SIMSITE COMPOSITE?
Simsite has a reading of "120" on the Rockwell M Scale for composites. Compared to most composites it is
very hard. We can add a ceramic coating to the material to make it much harder which helps against abrasion
attack. However, Simsite impellers should not be use in heavy abrasive or "trash pump" applications.
30.) WHAT IS THE MAXIMUM RECOMMENDED PERCENTAGE OF SUSPENDED SOLIDS THE
SIMSITE MATERIAL CAN WITHSTAND?
We recommend that Simsite Impellers not be used in solutions with greater than 15% solid matter or granular
solids in solution.
31.) WHAT GRADE OF SIMSITE® CAN WE USE WHEN WE CAN NOT USE ANY MATERIAL
THAT CONTAINS GRAPHITE?
Simsite grade SMS-250 has almost the same properties as our standard marine grade Simsite SMS-300 only
it does not have any graphite or carbon reinforcement. Instead we use a combination of other reinforcements
which have no effect on the medium being pumped including smell or taste.
32.) WHAT IS THE DIFFERENCE IN TEMPERATURE LIMITATIONS BETWEEN THE DIFFERENT
GRADES OF SIMSITE?
Our standard grade of Simsite SMS-300 is good up to 300 deg. F. Above that temperature we must switch to
a high temperature resin Simsite SMS-400 when we are manufacturing Simsite to achieve a limit of up to and
including 400 deg. F. continuously.
33.) WHAT IS SIMSITE EPOXY COATING?
As is well known in the industry, one of the largest problems in a pump, aside from the wear of metallic
impellers and casing rings, is the erosion, corrosion, and cavitation damage on the inside of the pump
casing. These pump problems will be substantially reduced with the installation of Simsite Impellers, Casing
Rings and the use of Simsite Epoxy Coating on the casing volutes.
Simsite Coating is the result of long research and development and will give supreme protection to the
inside of pump casings, pipes and heat exchanger covers, as well as many other applications where erosion
or corrosion is a problem.
Simsite Epoxy Coating is a two part coating used to line the casing volutes and protect the casing against
corrosion, erosion and cavitation damage. Simsite Coating is a two part mixture utilizing an epoxy resin
system, Simsite fiber reinforcement, and a special hardener. For ease of application and convenience, the
Simsite Coating is mixed in a 1 - 1 mixture of resin and hardener. The coating can be brushed on or it can be
put on thicker after it is allowed to set up with a spatula or a trowel. The set up time is 45 -60 minutes or it
can be expedited with a little heat. Simsite Coating has a maximum continuous operating temperature of 300
deg. F (150 deg. C). and is resistant to all organic and petroleum solvents as well as most acids and alkaline
solutions.
Coatings of any type work fine on stationary items but are not recommended for rotating equipment. For best
results the pump casing or metallic piece should be grit blasted, cleaned, warmed to remove any possible
moisture and then coated with Simsite Epoxy Coating.
34.) WHAT GRADE OF SIMSITE SHOULD I SPECIFY WHEN ORDERING NEW PARTS.
When ordering new impellers, rings or other parts, please specify Simsite Grade SMS-300. This is our
standard grade of Simsite composite, which is excellent in salt water, brackish water and most chemical
applications. Simsite Grade SMS-300 can withstand a vane tip peripheral speed of 500 ft./sec. pressures up
to 600 psi and can withstand 300 degrees F continuously.
Simsite Grade SMS-325 is our premium grade bearing material which contains two lubricants which are built
into the resin system. This grade is softer (65 of the Rockwell M Scale) and will support a longer life for the
shaft or sleeve on which the bearing is running.
For applications with temperatures over 300 degrees F but under 410 degrees F, please specify Simsite
Grade SMS-400. This grade of Simsite is manufactured with our high temperature phenolic resin.
Simsite Grade SMS-375 should be specified for slurry or abrasive conditions. This grade of Simsite utilizes
an epoxy resin system for greater abrasion resistance.
Should an application require a higher temperature or greater mechanical strength, please call the factory for
analysis.
35.) WHAT ARE THE STANDARD DELIVERY TIMES?
Our standard delivery time is as follows:
Simsite Impellers up to 20" diameter..................4 - 6 weeks ARO.
Simsite Impellers 20"- 48" diameter....................call the factory.
Emergency:
Simsite Impellers up to 24" in diameter.............1 - 2 weeks ARO.
Premium for the overtime:
1 week ARO...................................30%
2 weeks ARO.................................20%
Simsite Pumps.................................................10 - 12 weeks ARO
Simsite Epoxy Coating..................................... 1 - week ARO.
Simsite Casing Rings........................................1 - 2 weeks ARO.
Simsite Guide Bearings....................................1 - 2 weeks ARO.
Simsite Sleeves..................................................1 - 2 weeks ARO.
Simsite Split Rings............................................ 2 - 4 weeks ARO.
Simsite Split Guide Bearings........................... 2 - 4 weeks ARO.
Simsite Compressor Rings............................... 2 - 4 weeks ARO.
Simsite Condenser Door Covers...................... 2 - 4 weeks ARO.