Products > Mechanical Seals

Mechanical Seals Supply - Pumps & Rotating Equipment

Mechanical Seals

A.R. Thomson Group Inc. offers a comprehensive range of mechanical seals designed to handle the most demanding industrial applications, providing customers with high-quality and reliable sealing solutions. With our on-site experience and expertise, A.R. Thomson Group Inc. offers technical support, prompt delivery, and personalized service, ensuring customers receive the right mechanical seals and the assistance they need for successful installation and operation. 

Quality Assured:

A.R. Thomson Group Inc. maintains an ISO 9001:2015 Quality Management System. Manufacturing, assembly and distribution of CNC cut products, gaskets, sealing products and fasteners, distribution of instrumentation valves and fittings, and repair of mechanical seals.

Standard Stock Mechanical Seals:

  • Standard Cartridge Spring Seals
    Standard cartridge seals are pre-assembled mechanical seals designed for common industrial applications, offering a convenient and efficient solution by integrating all the necessary sealing components into a single, easily replaceable unit.
     
  • API Cartridge Seals
    The 9000 series pusher seals are all stationary flexible element as a standard. Available in single and dual cartridge. Mechanical seals for the oil & gas industry.

  • Split Seals
    Single and double split seals.

  • Special Duty
    Slurry, gas liftoff, mixer. 

  • Single Spring Seals
    Component style seals to replace most common OEM designs.

  • Bellows
    Chem Pro, TBH, TBS.

  • Mechanical Seal Repair
    Repairs, seal face refurbishment, seal reconditioning, reverse engineering, material upgrades, performance enhancement, custom solutions and seal failure analysis.

  • Seal Replacements for major brands
    John Crane, Flowserve, AES, Chesterton, Eagle Burgmann and More.

Downloads:

Standard Cartridge TAC Brochure

API Cartridge Seals Brochure 

Mechanical Seal Repair Brochure


Mechanical Seals Cartridge
Cartridge Mechanical Seals

Cartridge mechanical seals are pre-assembled units that provide a convenient and efficient sealing solution for various industrial applications, ensuring reliable performance and ease of installation.



Browse Cartridge Seals 

Mechanical Seals Component
Component Mechanical Seal

Component mechanical seals offer a versatile sealing option as they allow for the replacement and customization of specific seal components, providing flexibility to meet specific requirements and optimize sealing performance in diverse operating conditions.

Browse Component Seals  

Mechanical Seal Repair
Mechanical Seal Repair

Mechanical seal repair involves diagnosing and addressing issues such as leaks, wear, or damage in the seal components, restoring the seal's functionality and extending its lifespan, ultimately saving costs compared to complete seal replacement.

Learn About Seal Repairs  


Question: What Does A Mechanical Seal Do? 

A mechanical seal is a critical component used in various rotating equipment, such as pumps, compressors, and agitators, to prevent leakage of fluids or gases between the rotating shaft and the stationary housing. It serves as an effective and reliable sealing solution to contain the internal pressure of the equipment and prevent external contaminants from entering the system. Here's what a mechanical seal does:

1. Prevents Leakage: The primary function of a mechanical seal is to prevent leakage along the rotating shaft. It creates a barrier between the high-pressure process fluid inside the equipment and the external environment. By maintaining this seal, it ensures that the process fluid or gas remains contained and doesn't escape, avoiding potential hazards and environmental issues.

2. Maintains Efficiency: A well-functioning mechanical seal is crucial for maintaining the efficiency of the equipment. By reducing or eliminating leakage, the system can operate at its designed capacity, ensuring optimal performance and minimizing energy losses.

3. Handles Different Fluids: Mechanical seals are designed to work with various types of fluids, including water, oil, chemicals, and gases. They can be customized with different materials and configurations to handle specific fluid characteristics and operating conditions.

4. Adapts to Operating Conditions: Mechanical seals are versatile and can adapt to a wide range of operating conditions, such as varying temperatures, pressures, and rotational speeds. Depending on the application, seals can be chosen to withstand extreme conditions, ensuring reliable performance across different environments.

5. Extends Equipment Life: By preventing fluid leakage and reducing wear and tear on the equipment, mechanical seals contribute to extending the lifespan of rotating machinery. They help to protect the shaft and other critical components from corrosion and erosion caused by contact with the process fluid.

6. Reduces Maintenance Costs: Reliable mechanical seals require less frequent maintenance compared to traditional packing seals. This leads to reduced downtime and maintenance costs, making them a cost-effective sealing solution in the long run.

7. Increases Safety: Mechanical seals play a vital role in ensuring the safety of personnel and the environment. By containing hazardous or volatile substances, they help prevent accidents, spills, and leaks that could pose health and environmental risks.

8. Minimizes Product Contamination: In applications where product purity is crucial, such as food and pharmaceutical industries, mechanical seals provide an effective barrier to prevent contamination from external sources.

9. Accommodates Shaft Movement: Rotating equipment experiences shaft movement due to thermal expansion or other factors. Mechanical seals are designed to accommodate these movements while maintaining a reliable seal, ensuring smooth operation of the equipment.

In summary, a mechanical seal is an essential component that ensures the efficient and safe operation of rotating equipment by preventing fluid leakage, minimizing downtime, reducing maintenance costs, and extending the equipment's lifespan. Its ability to adapt to various operating conditions and handle different fluids makes it a widely used sealing solution in numerous industrial applications.

5 Common Mechanical Seal Failures (And How to Prevent Them)

Mechanical seals are critical components in rotating equipment like pumps, compressors, and mixers, tasked with preventing fluid leakage along the shaft. Despite their precision engineering, they remain a common point of failure, leading to costly downtime, environmental hazards, and safety risks. Understanding the most frequent failure modes is essential for effective maintenance and prevention. Here are the top culprits:

  1. Dry Running (Lubrication Failure):

    • Cause: This occurs when the seal faces lack the fluid film they rely on for lubrication and cooling. It can happen during startup before fluid reaches the seal, during process upsets causing loss of suction, or due to improper venting of air or vapors trapped in the seal chamber.
    • Symptoms: Rapid, catastrophic failure. Severe scoring, cracking, or even melting of the carbon face (often visible as deep grooves or bluish discoloration). A distinct high-pitched squealing noise may be audible. The elastomers (O-rings) can also be charred or hardened.
    • Prevention: Ensure proper pump priming and venting before startup. Implement adequate minimum flow recirculation systems. Consider dual seals with a barrier fluid system for applications prone to vaporization or intermittent service. Use seals designed to handle brief periods of dry running if unavoidable.

  2. Heat Degradation (Thermal Failure):

    • Cause: Excessive heat at the seal faces is a primary enemy. Sources include high process temperatures, insufficient cooling (jacket failure, clogged lines), high pressure causing excessive face load, or poor heat dissipation due to inadequate flush plans or incorrect seal design for the application.
    • Symptoms: Carbon faces show signs of blistering, charring, or excessive wear. Elastomers become hard, brittle, cracked, or compressed (taking a permanent "set"). The seal may leak excessively, often with discolored fluid or signs of coking.
    • Prevention: Ensure the seal is correctly rated for the operating temperature and pressure. Implement appropriate seal flush plans (API Plans) like Plan 21 (recirculation from discharge through a cooler) or Plan 23 (recirculation through a cooler and back to the seal chamber via a pumping ring). Maintain cooling systems diligently. Select materials (e.g., SiC faces, perfluoroelastomers) suitable for high temperatures.

  3. Chemical Attack (Incompatibility):

    • Cause: The seal materials (face materials, elastomers, metal components) are incompatible with the process fluid or cleaning chemicals. This can cause swelling, shrinking, dissolution, embrittlement, or corrosion.
    • Symptoms: Elastomers may swell significantly, become soft and gummy, or shrink and crack. Face materials can show pitting, etching, or discoloration. Metal parts (springs, drive pins) may corrode or weaken. Leakage often starts gradually but accelerates.
    • Prevention: Thoroughly analyze the entire process stream, including trace components, cleaning agents, and potential upsets. Consult material compatibility charts and seal manufacturer databases. Select chemically resistant materials (e.g., Viton®/FKM for many chemicals, EPDM for water/steam, PTFE for aggressive fluids, SiC or alumina faces). Consider dual seals with a compatible barrier fluid.

  4. Installation & Handling Errors:

    • Cause: Improper installation is surprisingly common. This includes incorrect setting of spring compression (too tight causes excessive heat/wear; too loose causes leakage), contamination of seal faces or O-rings with dirt or grease during installation, misalignment of the seal faces, damaging O-rings during assembly, or using incorrect tools.
    • Symptoms: Leakage immediately upon startup or shortly after. Premature, uneven wear patterns on the faces. Cut, nicked, or twisted O-rings. Visible damage to seal components.
    • Prevention: Follow manufacturer installation instructions meticulously. Work in a clean environment. Use proper installation tools (sleeves, setting tools). Ensure shaft/sleeve runout and end float are within tolerance. Train maintenance personnel thoroughly. Handle seals with care, avoiding impacts or dropping.

  5. Vibration & Misalignment:

    • Cause: Excessive vibration from the pump (imbalance, cavitation, bearing failure, poor foundation) or significant shaft misalignment puts dynamic stresses on the seal. This can cause face separation, hammering, and accelerated wear of drive mechanisms (pins, set screws).
    • Symptoms: Intermittent or erratic leakage. Visible fretting or wear on the shaft/sleeve under dynamic O-rings. Loosened or broken drive pins/screws. Premature bearing failure often accompanies seal failure.
    • Prevention: Address the root cause: balance rotating elements, eliminate cavitation (ensure adequate NPSH), maintain bearings properly, align the pump and driver meticulously (using laser alignment is best), ensure a rigid foundation. Consider seals with more robust drive mechanisms or anti-vibration features if vibration is inherent to the process.

By recognizing these common failure modes and implementing proactive prevention strategies – proper selection, correct installation, diligent maintenance, and addressing root causes like vibration or heat – operators can significantly extend mechanical seal life, enhance reliability, and reduce the total cost of ownership for their critical rotating equipment. Consulting with seal specialists during the selection and troubleshooting process is invaluable for achieving optimal performance.