Step-by-Step Instructions for Installing Mechanical Seals in Centrifugal Pumps
June 5, 2023
Understanding the Role of Mechanical Seals in Preventing Pump Leakage
August 8, 2023
Understanding the Differences Between Mechanical Seals and Pump Packing
Introduction
Without a sealing mechanism, process fluid can easily leak out of pumps via the gap surrounding the pump shaft. Hence, to reduce leakage from pumps, effective sealing technology is needed.
For years, pump packing has been used to minimize leakage; however, with the technology evolution, mechanical seals have come into play for reducing leakage and minimizing the space between the shaft and pump housing.
So which is the best sealing technology for your pump – Mechanical Seals or Pump Packing? There are pros and cons for both mechanical seals and pump packing, so in this blog, we will compare their advantages and disadvantages and determine which is better for your application.
What Is A Mechanical Seal?
A mechanical seal is renowned due to its excellent sealing capability that offers better prevention of leakage of fluid than other methods.
It is used to seal the rotating part of the pump shaft against the stationary part of the pump, which prevents the leakage of fluid into the external area.
Mechanical seals can efficiently sustain aggressive operating conditions and corrosive fluids to ensure the prevention of any fatality or accidents.
There are many types of mechanical seals available in the market for various types of applications. Every mechanical seal has different types of components; however, below are some of the common components of the mechanical seal.
- Rotating Face: It is the main moving component of the seal that is connected to the rotating shaft.
- Fixed Face: It is a stationary part connected to the pump housing.
- Secondary Sealants: It is present between the two faces of the mechanical seal shaft and insert mounting.
- Hardware: Some of the common hardware components used in mechanical seals are pins and billows, glands, compression rings, etc.
What Is Pump Packing?
Pump packing is a traditional method of stopping leakage. They are often braided and fibrous materials rings that are stuffed into the seal chamber between the rotating equipment and the pump body.
By gland tightening against the external ring, the generated pressure is distributed to the pump packing sets. This results in external ring expansion which creates a seal.
However, pump packing does not provide a stoppage to full leakage. It is just kept loose to allow the liquid flow to drain out during operation to generate flushing action, which prevents overheating and excessive wear between the inside and outside of the packing surface.
Differences Between Mechanical Seals and Pump Packing
Pros And Cons Of Mechanical Seals
Mechanical seals are the best option for applications where higher leakage assurance is required. These seals provide safer working conditions, less bearing failure, and pump shaft damage. They are suitable for effectively handling hazardous liquids like petroleum or chemicals.
Pros Of Mechanical Seals:
- Energy Efficient:
They don’t create friction on the rotating pump shaft, which makes it highly energy efficient due to the lower consumption of energy.
- Long Service Life:
The right maintenance and installation prevent pump shaft damage and make them reliable for a longer period of time.
- Low Maintenance:
They require less maintenance, which saves time as well as reduces breakdowns. Thus, pump operations run smoothly without interruption month after month.
- No Leakage:
The major advantage is that leakage problems in the shaft rarely happen; hence, it is ideal for toxic and corrosive applications.
Cons Of Mechanical Seals:
- Expensive:
They require high investment in comparison to pump packing. However, mechanical seals can run for years without adjustment or failure.
- Wear & Tear:
They are durable and sturdy; however, they work under constant pressure and temperature, and this causes wear and tear. Hence the mechanical seal service life depends on the operation conditions, type of liquid, and duration of the operation.
- Require Lubrication:
Depending on the application, proper lubrication is required to avoid seal damage. More importantly, the dry run should be strictly prevented as it can completely damage the seal.
- Higher Downtime:
They usually don’t require maintenance, but when it does, they require more downtime. Maintenance and repair downtime is high as the pump needs to be taken out for mechanical seal replacement.
Pros And Cons Of Pump Packing
Pump packing is an old but most popular method to prevent leakage. It is widely used due to its simple design, quick installation, and low cost.
Pros Of Pump Packing:
It is made of soft non-metal materials, which makes it a cheaper option in comparison to mechanical seals.
- Low Cost:
It is made of soft non-metal materials, which makes it a cheaper option in comparison to mechanical seals.
- Quick Installation:
It doesn’t require decoupling of the drive shaft; hence it can be easily installed.
- Easy Maintenance:
At the time of breakdown, the maintenance is simple and quick, which minimizes operation downtime.
Cons Of Pump Packing:
- More Leakage:
It is expected to leak and can’t assure 100% leakage-proof. Without leakage, the pump packing will burn and cause wear groves into the pump shaft and sleeves. Also, it is not suitable for handling expensive, explosive, and toxic liquids.
- Frequent Maintenance:
It requires constant repair, maintenance, and attention in order to check if there’s any wear and tear.
- Low Energy Efficient:
Improper pump packing can lead to higher power consumption via rotating equipment.
- Wear & Tear:
It can’t handle corrosive materials and high temperatures; hence corrosion problems, bearing failures, and more are possible.
Mechanical Seals Vs Pump Packing: Which Is Right For Your Application?
So, here you know the difference between mechanical seal and pump packing, but which one to use for your application?
Both pump packing and mechanical seals are effective and useful. The selection mainly depends on personal preference and requirement specifications.
However, mechanical seals are highly preferred by industries due to their significant advantages over pump packing. Those advantages are low maintenance, cost-effectiveness, higher leakage prevention, and longer service life.
Bottom Line
If you have decided to make a switch from pump packing to mechanical seals, contact a trusted mechanical seal manufacturer to help you with the right seal for your application.
Mechanical seals are a substantial investment; hence, it is best to get them from the best. Popular Pump Seals is a leading mechanical seal manufacturer in India specializing in providing the best mechanical seals for all types of leakages.
To know more about Mechanical Seals, contact us today.
