There are many types of seals used in industry, each with its advantages and disadvantages. Two of the most common seals are mechanical seals and gland packing. There are a few differences between mechanical seals and gland packing like cost, use, and seals.
What Is A Mechanical Seal?
Mechanical seals are sealing devices that use a variety of mechanisms to create a seal between two surfaces. Common mechanisms used in mechanical seals include O-rings, gaskets, and lip seals. Mechanical seals are typically made from metals or plastics and can be used in various applications, including pumps, valves, and compressors.
What Is Gland Packing?
Gland packing is another type of seal that is commonly used in industry. Gland packing is typically made from braided fibers, such as asbestos, graphite, or PTFE. Gland packing is used to seal reciprocating shafts, such as those found in pumps and valves. Gland packing is also commonly used in static applications, such as sealing pipe joints.
Difference Between Mechanical Seal And Gland Packing
- Purchase Cost: A gland packing will cost anywhere from a few dollars to a couple of hundred dollars per installation. A mechanical seal can cost upwards of $1,000 or more per unit.
- Installation Process: Gland packing is a less precise way of sealing. It usually requires equipment disassembly, and the old packing must be removed and replaced with new packing material. Almost anyone can do this process with some basic mechanical skills. An automatic seal installation requires special tools and knowledge to install the seal properly.
- Ongoing Maintenance: Gland packing will need to be replaced periodically as it wears out. Anyone can do this with basic mechanical skills. Mechanical seals generally do not require much maintenance, but they may need to be adjusted or replaced if there is a problem. Overall, mechanical seals are more expensive than gland packing but are also more precise and require less maintenance.
- Energy Usage: Gland packing generally requires more energy to operate than a mechanical seal. This is because gland packing tends to leak more, which causes the equipment to work harder to maintain the desired pressure.
- Life Expectancy: Gland packing will typically last for a few years before it needs to be replaced. Mechanical seals can last for many years or even decades, with proper maintenance.
- Operational Costs: Gland packing will typically cost more to operate than a mechanical seal. This is because gland packing tends to leak more, which causes the equipment to work harder to maintain the desired pressure. Overall, mechanical seals are more expensive than gland packing but are also more precise and require less maintenance.
- Environmental Risk: Gland packing can pose an environmental risk if it is not correctly disposed of. This is because gland packing is made of materials that can harm the environment. Mechanical seals are also made of materials that can damage the environment, but they are less risky than gland packing.
- Predictable lifetime: One of the main benefits of a mechanical seal is its predictable lifetime. A mechanical seal can last many years, or even decades, if properly maintained. Gland packing will typically only last for a few years before it need to be replaced.
When Should You Use Packing Seals?
- Packing seals are most commonly used in low-pressure applications, such as domestic water pumps.
- They can be found in some automotive applications but are not well-suited for high-pressure or high-temperature environments.
- Packing is also more likely to leak over time than a mechanical seal.
When Should You Use Mechanical Seals?
- Mechanical seals are often chosen for their superior performance compared to gland packing.
- Mechanical seals are used when gland packing cannot provide an adequate seal.
- A mechanical seal is usually the best option when you need a reliable, long-lasting seal that can handle high temperatures and pressures.
Why Do Pumps Need To Be Sealed?
Pumps are designed to move fluids, whether water, oil, or something else. But for the pump to work correctly, the fluid being moved has to stay inside the pump and not leak out. That’s where seals come in. Seals are necessary to keep the fluid being pumped inside the pump, and they also help to prevent contamination of the fluid by keeping outside elements from getting in.
Are there any disadvantages to using a mechanical seal?
Yes, there are a few disadvantages to using mechanical seals. One is that they can be more expensive than other types of seals. Another is that they require more maintenance and can fail if not properly maintained.
How can I prolong the life of my gland packing?
Proper installation and regular maintenance are the best ways to prolong the life of your gland packing.
What are the most common causes of gland packing failure?
The most common causes of gland packing failure are improper installation and lack of maintenance.
There are many differences between mechanical seals and gland packing. Both have advantages and disadvantages that must be considered when choosing which one to use. In general, mechanical seals are much more reliable and efficient than gland packing, making them the better choice for most applications.