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Knowing whether or not to seal your application is relatively simple. Knowing how to seal can be a challenge in certain operations depending on the environment and product being sealed. Here are a list of reasons of why an operation needs to be sealed and its benefits:
Does Your Operation Leak?
The simplest way to tell if you should seal your machines and operations is to check if there is any kind of fluid leakage, even if the only leakage is sanitary room temperature water that can cost money over time. Sealing any kind of benign leak is a matter of cost-benefit analysis. If the cost of a seal and replacing it as it wears down is higher than the money saved when the leak is nontoxic and not a slipping hazard, then don’t seal it. Realistically, those situations are extremely few and far between.
Most leaks will cost money over the long and even short term. Loss of product is often an easy way to ruin profitability. While your product may be benign, it can still become a health hazard if ingested through particulates in the air. The possibility of a slipping fall is also very real and can cause a worker’s compensation situation.
The leakage may also wear down the machines by causing rust, erosion, or additional friction in any moving parts.
Are Fumes a Problem?
Fluid isn’t the only thing that escapes through gaps in machinery. Fumes can be even deadlier, being invisible or slow-acting in their toxicity. Many products now require zero-emissions due to environmental regulations. Short term savings are not worth pursuing over potential fines or worker health issues. The toxicity of the emitted vapors is not the only factor to consider. Temperature can be an issue, as well. Extremely hot or cold air escaping machines can be dangerous to workers and the machines themselves.
Do Pressure and Heat Need to be Maintained?
Some operations require that their product be kept under certain pressure conditions. If a machine isn’t sealed properly, the pressure level will drop and may even cause a rupture if fluid or air escapes too quickly. If an application requires the escape of pressure, seals can be made to compensate for this need.
The same can be said for temperature. A seal can ensure that heat doesn’t escape or enter through a space in the machine, helping to regulate temperature.
Is There Friction?
When metal rubs against metal it wears down, vibrates, and damages machinery. So, even if there isn’t product loss or the escape of dangerous material, it may be necessary to seal joints. Dislocation and misalignment of machines can cause catastrophic damage and failure. Even just vibrations can cause these same issues over time. Seals can act as a buffer and dampener for these forces, saving the machinery from damage.
Is Contamination a Concern?
Fluids, solids, and vapors escaping aren’t the only concern. The inverse can also be just as big of a problem; invasive particles or liquids can wreak havoc on an operation. Contamination can cause massive loss of product, making the entire operation shut down so it can be cleansed from the systems. These contaminants can also damage the machines themselves. Keeping out material is often just as important as keeping it in.
Still Unsure?
Are you still unsure whether your application requires seals? Before moving forward you should be one hundred percent certain if you are going without seals. If you need help deciding how to seal, or whether you need to seal, consulting an expert is the right decision. Contact Real Seal today to discuss all your sealing needs.
In a centrifugal pump, a component or cartridge seal may be interchanged, depending on the application. By understanding the advantages and disadvantages of each, you can ensure the optimal performance of your pump.
Component Mechanical Seals
Most standard mechanical seals fall under this category. Replacements of these seals typically include seal faces, holding brackets, O-rings, boots, and parts which must be installed by an experienced pump technician. This is important, as the seal housing’s limited access requires a precise and accurate hand. If just one component is installed incorrectly, the risk of seal failure will increase significantly. There are many components of the seal which need to be installed just right, including seal faces which must be properly seated on the shaft or seal housing, and sliding O-rings and elastomers over shaft shoulders, key ways, and other parts. A mistake installing any of these parts can result in misalignment, damage, and incorrect seal tension.
Cartridge Mechanical Seals
While cartridge seals share many components in common with component seals, there are a few essential differences. Some of the parts come preassembled, like the stationary components which come in a housing; and the rotating components, which come on a shaft-mounted sleeve and are sealed with an O-ring or elastomer. Because of this, installation errors are far less likely.
A key part of successful seal installation is setting the spring tension. Component seals are set manually by adjusting the length of the seal’s spring. Cartridge mechanical seals, on the other hand, have preset spring tensions. A retaining device is used during the installation process to hold the rotating and stationary elements in alignment.
Whether you will be able to install a cartridge mechanical seal will depend on many complex factors affecting the pump. One of the main factors is which side the seal installs from. Most cartridge mechanical seals cannot be installed on the wet side of a pump’s seal chamber, behind the impeller. These seals are generally incompatible with submersible pumps for a similar reason.
Comparing the Two
Deciding between the two seals largely depends on the cost and ease of installation. While the presence of a competent pump technicians might make ease of installation seem like a non-issue, being able to replace a seal during an emergency outage should be a concern.
Unfortunately, cartridge seals cost two to three times more than component seals, so most competitive repair bids you will see often refer to component seals. Although they cost more upfront, in the long-term, cartridge seals are more cost-effective. While component seals require in-service replacement, cartridge seals require less labor costs and less production lost from seal replacement. You’ll also save money on potential errors resulting from potential installation errors of component seals.
In short, mechanical seals are the best choice for users who need a long-term, cost-effective solution for pump maintenance, while component seals are best-suited for users who place a higher priority on a lower upfront cost. For more information or seals and other related components, visit Real Seal.
Are you confident that your system is protected against a seal failure? If not, it could mean a significant setback in production and costs you didn’t have to spend. Protect the investment you invested in by taking these four steps.
1. Choosing the Right Seal
The application, operating conditions, and off-design usage of the seal must be considered carefully before purchase. Even if you simply need a seal to function in hot water, not any seal will do. Boiler feedwater, for example, will not properly lubricate and cool seal faces, resulting in premature seal failure if the wrong seal is installed.
The user must therefore determine that proper operating parameters are maintained. Then, contact must be made with the seal supplier to choose the correct American Petroluem Institute (API) flush plan, seal face combination, and elastomer. It is important to ensure that the proper seal is in place, since every application has its own unique requirements.
2. Proper Installation
Many seal failures could have been prevented simply by a proper installation. Too often, seals are installed without referencing the manufacturer’s instructions, or without taking the proper care to prevent damage on the seal faces or O-rings. Some of the more common issues include: forgetting to tighten set screws before removing setting clips, damaging O-rings, and not tightening gland bolts evenly. Many of these issues can be avoided simply by opting for a cartridge seal over a component seal. The cartridge seal has many of the delicate parts preassembled, reducing the chance for errors significantly.
3. Prevent Excess Heat Generation
Heat generation between seal faces can reduce a seal’s life dramatically by causing problems such as dry-running. The cause is often due to a flooded pump, or an incorrectly vented seal chamber before startup. Another cause might be shaft runout or elevated vibration.
For nearly every application, API 682 will almost always be recommended. No matter if you decide on Plan 11 (a flush line from pump discharge) or Plan 13 (recirculation to pump suction), these systems will keep the seal faces clean, cool, and well-lubricated. Your seal support system will also have an impact on the success of your system. Be sure to discuss these carefully with your seal manufacturer to ensure a cool-running seal.
4. Manage Proper Storage Conditions
Mechanical seals have many unique parts comprised of various materials. If you are not aware of the environments the seals must be stored in, the seals may lose a considerable amount of functionality due to the delicacy of their components.
The seals must be stored in a clean environment, where the temperate and humidity are regulated. If proper care is taken, seals may be stored effectively for up to five years.
Different steps must be taken depending on how long the seals will be stored. A new seal being stored for the next two years should be placed in a clean and cool environment. To prevent face lock and loss of face flatness, rotate the seal faces against each other using the sleeve or shaft two turns every three months, if the seal is not being used.
For new seals being stored for more than two years, or for a seal that has already been in use and will be stored for more than a year, the process is more complicated. Disassemble the seal, clean and dry every component, then store each of its parts individually. O-rings must be in a relaxed state, and placed in their proper environmental conditions, depending on its material. Plug all openings of the seal’s gland in addition to the pump’s seal chamber (if it has not been used). Seal faces should be separated and stored in separate bubble-wrapped packages.
When reassembling the seal after storage, check O-rings for cracks, cuts, and wear. Then, lubricate them to facilitate assembly. Be sure to replace damaged or compression set O-rings. Check the mating ring for cracks or chips, paying special attention to the sealing faces. Contact the vendor for a replacement if damage is found.
To purchase seal components or to learn more about them, please visit Real Seal.
There are many options when it comes to choosing a rubber seal. The profiles can be made of elastomeric compounds through the process of molding or extrusion. The lengths needed for the application are then custom-fabricated from standard rubber products.
There are many different rubber molding processes, including injection, compression, transfer molding, and extrusion. Each process has its own unique advantages, but extrusion is capable of producing complex cross-sections and a smooth surface. These options are available with several different seals, including bulb, bulb trim, lip, door, and accordion seals. There are also extrusions available in solid rubber and sponge rubber, which may then be converted into specialty seals to suit your needs.
There are five different types of extruded seals to consider:
Bulb Seals
Bulb seals have either open, rounded, or teardrop-shaped areas that give them their characteristic look. There are less common shapes as well, such as the crescent and the flat-bottom. Physical dimensions vary, but they usually refer to the height of the inner and outer diameters. Bulb gaskets are typically made of sponge rubber, and are often placed within the door frame of a car or building. Softer bulb seals can be made with EPDM foam in order to create a watertight seal. When used in the automotive industry or construction, bulb seals may be taped instead of mechanically fastened.
Bulb Trim Seals
Bulb trim seals have both a bulb section and a trim section, each with its own durometer. The bulb is usually made from a medium-density sponge rubber such as EPDM. The trim portion is made from materials such as PVC. This unique design allows bulb trim seals to resist water, ozone, sunlight, and temperature extremes. They also come in thermoplastic elastomers, which are weather-resistant, reusable, and recyclable.
Lip Seals
Lip seals have an edge or sealing lip, and sometimes even an opening. Lip seals protect bearings attached to rotating shafts or bores. They retain the lubricant of the bearing, while also preventing dust and other contaminants from entering the seal. One variation on this seal is the radial lip, used in high-speed crankshaft mechanisms found in diesel and gasoline engines.
Lip seals are common in other applications, such as various industrial machines, vehicles, pumps, and mills. If you need this type of seal, choose a material with the right properties for your application.
Door Seals
As their name implies, door seals fill gaps between doors and door frames in order to keep the elements out of vehicles and buildings. Unlike the other extruded seals on this list, door seals are defined by the application they are used in, rather than their shape. Door seals are commonly found in cars and trucks, as well as construction, residential, and industrial facilities. A subset of the door seal known as the hatch seal is used in fuel tanks, electronic enclosures, and rooftop HVAC systems. Certain types of bulb seals also fall under the category of door seals, but these door seals have custom weather stripping as well.
Accordion Seals
Like accordions, accordion seals have folds which allow them to change their dimensions when stretched or compressed. This property makes seals like the accordion boot seal useful in automotive and transportation applications, such as weather-proofing the access points between a truck cab and a trailer. Accordion seals are made from EPDM rubber, and may even contain an internal spring steel loom.
To learn more about the extruded seals available for your application, contact the experts at Real Seal today.
Rubber products, or elastomers, are useful in a wide variety of applications. From industrial seals to medical products, rubber products are an important part of many industries. There are, however, a wide variety of elastomer choices, making it difficult to decide which one is best for your particular application.
One elastomer which many find particularly useful is silicone. Silicone has a number of properties that make it the first choice for many applications.
Temperature Resistance
Silicone is an excellent choice for many applications because it retains elasticity under extreme temperatures. Unlike the material found in rubber bands, silicone does not lose elasticity or become brittle in colder temperatures, and resists damage even at much higher temperatures. Silicone is even used in paint to make the exteriors of houses more resistant to freeze and thaw cycles. Whether the application involves extreme cold, extreme heat, or both, silicone will be an excellent choice.
Flame Retardancy
It takes a lot to make silicone catch fire. This makes it particularly useful in consumer electronics, which need to self-extinguish quickly in case of emergency. For this reason, silicone is used in sealing joint components found in computers and small appliances. It is also commonly found in commercial ovens, food carts, and other industries where higher temperatures are a concern.
Permeability
Silicone’s permeability makes it very useful in applications where the elements are an issue. By using a silicone seal in the door of a car or house, or even the cockpit of an aircraft, silicone will seal out even the most extreme elements.
Durability
Silicone’s durability makes it a common component in the medical industry. Silicone is used as a material for implants because it is accepted by the body, withstands a lot of wear and tear, and allows certain substances to pass through it. These properties also make it useful as a seal covering a wound, protecting it as it heals.
Silicone offers a wide variety of advantages that might make it the best choice for your application. Whether you need gaskets, O-Rings, hoses, door seals, or implants made, silicone is a great choice for many jobs. To learn more about silicone and its applications, contact the experts at Real Seal today.
Rubber seals are some of the most versatile products out there, and navigating the vast array of seals available can be daunting on your own. To help you determine which rubber seal is right for your needs, refer to these rubber seal categories conveniently outlined below:
Silicone
Silicone is a material which demonstrates high resilience, temperature stability under extreme heat, and inertness. Silicone comes in several different forms, such as solid, sponge, and foam. Each of these forms has its own special advantages.
Silicone sponge has a closed cell structure, making it ideal for environmental sealing. It can be either soft (2-5 psi) or firm (in the 14-20 psi range).
Like silicone sponge, silicone foam has a closed cell structure and remains stable under UV light.
Other advantageous properties of silicone include being waterproof, flexible (protecting it from damage at extreme temperatures), and shrink-proof.
Neoprene
Neoprene is a type of synthetic rubber made of polymerized chloroprene, which forms a permanent seal. With resilience, tear-strength, and resistance to both UV and ozone damage, neoprene can be a very useful material as long as it avoids petroleum-based fuels. It has excellent resistance to temperatures as low as -40°F and as high as 250°F. Neoprene is also resistant to water and corrosion.
Urethanes
Urethane is a flexible, waterproof, and elastic material that also demonstrates aging and abrasion resistance. It is vulnerable to high temperatures, however. Urethanes come in a variety of blends and formulations.
EPDM
EPDM is a waterproof material with compressibility and aging properties which protect it from UV light, ozone, and oxidation. It comes in varying degrees of density. EPDM combines the closed structure of silicone with the wide temperature resistance of neoprene (from -60°F to 300°F).
This is just a sample of the many materials available at Real Seal. For more industry expertise, contact us today for all of your rubber seal questions and needs.
O-rings and other gaskets are most often used in static seal applications, meaning that the seal is attached and held firmly in place on a gland. Such applications are not damaged by friction or abrasion. If, however, the gland surface moves in relation to the seal, it is a dynamic seal that may require a lubricant to improve performance.
Dynamic applications have two additional factors to consider: break-out friction and running friction. Break-out friction refers to the force that initiates a seal’s movement, while running friction refers to the force needed to keep the seal in motion. Break-out friction can be up to three times greater than the force of running friction.
Choosing the Right Rubber Compound
Some compounds are better suited for dynamic applications than others. While nitrile and EPDM are suitable for dynamic applications, they do tend to have above-average break-out or running friction when used without lubrication.
Silicone and fluorosilicone have poor tensile strength, meaning that they rupture very easily. This makes them a poor choice for high-rate dynamic applications. Reserve these materials for low movement dynamic applications with smooth gland surfaces.
Fluorocarbon is significantly costlier than most other compounds, and cannot be used with steam. It does, however, have better temperature and chemical performance, as well as better running and break-out friction than most other elastomers.
Choosing a Rubber Seal Lubricant
Once you have chosen your material, an OEM engineering team will measure the friction on the seal. This will help you decide whether you need a lubricant to improve the efficiency or longevity of the seal.
External Lubricants
Hydrocarbon lubricants, as well as silicone and barium-based greases, can be applied to lubricants in-stock. These and powder-based lubricants (such as molybdenum disulfide and graphite) are often the best choice for initial reduction of friction. They are compatible with most elastomers and meet high temperature requirements. Additionally, they can provide extra protection from oxygen or ozone damage.
However, there are some negatives to consider as well. If the elastomer and the external lubricant are not chemically compatible, it may cause parts to stick together or otherwise impede assembly operations. Moreover, external lubricants may be lost through dilution into fluids which contact the seal, or through collection away from the seal.
Chlorination
Like external lubricants, chlorination can also be applied to stock O-rings. It is a permanent process which provides a smoother seal surface, reducing running friction. Though it has little effect on break-out friction, it can be used together with an external lubricant to great effect.
Internal Lubricants
Internal lubricants are friction-reducing agents like PTFE, graphite, and molybdenum disulfide, which are mixed into an elastomer. Due to the fact that an internal lubricant is chemically incompatible with the elastomer it is applied to, the elastomer will excrete the lubricant over time. Internal lubricants reduce friction, allow for more consistent performance, and have better assembly productivity in comparison to other lubricants. As with external lubricants, make sure that the internal lubricant is chemically compatible with the fluids it contacts.
Once your elastomer and lubricant are chosen, run the final tests to ensure optimal performance. To learn more or to purchase O-rings and lubricants, contact Real Seal today.
The word “seal” conjures up numerous images, depending on the person, but remarkably, we all use a number of devices that have seal systems every day. The water system in our homes must have a seal system in order to direct the flow of water to showers, sinks, washers, etc, and this becomes more complex when we add hot water heaters and water softening or RO systems. The quality, pressure, and in many ways the cost of your water system can be quite dependent on the sealing system utilized. When you drive a car, the fuel distribution system, hydraulic brake system, cooling system, suspension system, steering system, transmission, and air conditioning all depend on a solid seal system. Most consumer products are produced on an assembly line with extensive pneumatic systems which require seal systems for robotics. It is a unique field, but an extensive one… and Real Seal has more than 40 years of experience with seal systems here in San Diego.
Most engineers are trained in the mechanical engineering basics, or have a specific background in electronic, computer, civil, aeronautical, or other engineering disciplines. Seals and Gaskets have their own unique set of engineering driven features and constraints. When considering the performance of a seal system, the following is a basic framework for consideration:
- What is the media that the seal will be in contact with?
- What temperature is the application likely to endure?
- What physical constraints will the seal see (pressures, friction, elongation, set, etc)?
- Are there specific performance or longevity requirements?
- Are there regulatory requirements (FDA, NSF, ACS, etc)?
- Are there any special assembly requirements?
- Are there any aesthetic requirements?
Once these basic questions are answered, Real Seal engineers can normally make the best material recommendation, and provide design support for the application.
Real Seal has developed a multitude of materials for specific applications, and many have proven to be quite challenging. Examples of successful seal system material development would include:
- An FKM material developed for the soft drink dispensing industry, which stands up to the wide range of soft drinks on the market today. Although it may seem mundane from the outside perspective, the chemistry of today’s soft drinks covers the gambit of ph, and many of the newer energy drinks have ingredients which can be quite harsh on dispensing systems. The Real Seal material stands up to all of these drinks, and does not swell like conventional materials, which allowed a precision solenoid valve to work flawlessly. The material also passed Coke’s taste test, and was submitted for NSF approval.
- A Silicone material developed for the Integrated Circuit chip manufacturing process, when the chips are cured in a vacuum tube. Conventional seals were degrading in the high heat environment, and the smoke that was emitted contaminated the chips… the new silicone alleviated this issue.
- An EPDM material formulated to stand up to a high shear strength challenge in a filter application. The EPDM material had to be formulated to meet a number of regulatory requirements, including NSF, ACS, and WRC, yet still have physical properties that would withstand tensile and tear strength requirements that other materials fell apart in. Real Seal developed the material in less than (30) days, and had prototypes in the hands of the engineer within days of development. The material worked, and is now specified in multiple applications throughout the products the customer sells.
Real Seal has developed a unique way to provide seal systems across numerous applications, and do it quickly and effectively here in San Diego. For your challenging seal system needs, please consider Real Seal as a resource to help overcome the challenges that the market brings to your high performance products.
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