By Todd McMonigle

When repairing a pump that currently has a component mechanical seal* (or packing**), it is worth considering upgrading to a cartridge mechanical seal design. Component seals include multiple parts (rotor, rotor face, stationary face, springs, O-rings, gaskets, and seal gland) that require considerable handling and also require more care and skill during installation. For this reason you can incur potentially more assembly errors, including wrong spring setting—and therefore improperly loaded faces, dirt or grease contamination on sealing faces, damage to sealing components from mishandling, and sometimes just plain forgetting to use a needed part (like omitting a gland gasket…been there!). Any of these will result in immediate or early failure of the mechanical seal.  (Note: It is always a good idea to air test—at 25 psig—a rebuilt pump on the bench prior to putting it back into service).

On the other hand, a cartridge seal is a FULLY pre-assembled mechanical seal. It includes all of the parts mentioned above in the component seal (plus a seal sleeve), but in a prepackaged, preset, factory assembled and factory-TESTED product. All of the potential issues mentioned above with a component seal are eliminated with a cartridge seal. As with any mechanical seal installation, however, careful attention must be paid to proper installation practices and techniques—regardless of whether it’s a component or cartridge seal. Also, cartridge mechanical seals can sometimes require additional seal chamber clearance or axial space requirements; that is another reason to consider upgrading during a pump rebuild, when you have the tools and machining capabilities readily at hand (if needed).


  • Installation time is reduced considerably compared to a component seal installation
  • Seals come with installation grease, tools, a detailed drawing, and sometimes extra set screws and O-ring materials
  • Multiple features, seal designs, materials, single and double configurations, and internal interchangeability
  • Most manufacturers offer “half-price” repair programs or exchanges, often regardless of the poor condition of the seal
  • Manufacturers also provide further deep discounts on new seals when converting a competitor’s cartridge seal

For more information about component and cartridge mechanical seals, contact an OTP Industrial Solutions expert. Our team takes pride in the technical knowledge and broad product support we provide to help our customers build and maintain top performing industrial systems.

*Mechanical Seal – precision sealing device used to virtually eliminate process fluid leakage (as
low as 3 drops/day) along the pump shaft or other process equipment shaft.

**Packing – early method of sealing the pump shaft by means of compressing or squeezing
together multiple flexible rings or “ropes” to create a seal. Generally leakage rates are required to
be a minimum of 60 drops/minute and are often times much greater. Packing is still used today
quite extensively.

Flowserve Pumps and Seals

OTP Industrial Solutions has a been an authorized Flowserve distributor for almost five decades, originally partnering with Flowserve (Worthington Pump at the time) in 1963.  OTP capitalizes on this long history with factory trained associates to provide the best pump and mechanical seal for each application.

Related Photos: OTP Pump Applications – PHOTOS
Product Info: Flowserve Pumps
Product Info: Flowserve Mechanical Seals
Related Article: OTP Industrial Solutions Expands with Flowserve Seals

Flowserve Seals Authorizes OTP in Indiana

INDIANAPOLIS, INDIANA – Flowserve Mechanical Seal Division has expanded it factory support with OTP Industrial Solutions into most of Indiana, Ohio and Kentucky.

OTP Industrial Solutions has been a Flowserve Pump distributor for over four decades and is now expanding this long relationship by moving to Flowserve for mechanical seals applications. “OTP supports a wide range of pump applications,” states Tom Bland, OTP Fort Wayne Manager since 1980. “Flowserve, as the industry leader in both pumps and mechanical seals, complements our broad product line to enable us to deliver complete customer solutions.”

OTP has expanded its mechanical seal inventory in Indiana to include nearly every standard mechanical seal configuration.  This inventory supports both 1-3/8” and 1-7/8” shaft sizes, and is immediately available for new applications and pump repairs.

Utilizing its many experienced pump associates, OTP supports Flowserve with the unique “Ask the OTP Experts” on-line industrial product technical support.  This feature enables the user to easily find technical information about pump related products, and to quickly obtain specific answers to their automation and control questions. “Ask the OTP Experts” enables maintenance, purchasing and engineering associates to easily connect with local technical OTP experts in pumps, fluid power, fluid dispense, mechanical power transmission, bearings, electrical and automation products.

Dave Parks
3192 N Shadeland Ave
Indianapolis, IN 46226

Flowserve ISC2 Mechanical Seals Now in Stock

OTP Industrial Solutions has expanded its mechanical seal inventory to include the newly introduced Flowserve ISC2 family of mechanical seals.

“We are stocking nearly every standard seal configuration possible to service the Durco Group I and Group II pumps,” states Tim Davis, Pump Specialist. “We have both 1-3/8” and 1-7/8” shaft sizes to support both large bore and standard bore stuffing boxes.”

The Flowserve ISC2 Series is a complete family of mechanical seals that provide exceptional reliability and standardization over a wide variety of industrial applications. It is the preferred mechanical seal for ANSI and general service pump applications and the seal design is so versatile it may be the only seal required by some facilities.  Facilities that standardize on the ISC2 will benefit from less inventory, greater flexibility, rapid availability, less downtime, and longer seal life.

The ISC2 mechanical seal introduces new technology exclusive to Flowserve and offers many upgrades to competitive seals.

  • Exclusive Thermal Management Technology – tolerates dry running and cavitation events associated with “bad actors”.  The addition of carbon graphite between the rotary face and metal components acts as a heat sink to lower seal face generated heat.
  • Square Head Pin – centered in the rotary face the square head self-aligns to evenly distribute torque loads, thus reducing face fractures.  The torque carrying capability is three times that of similar competitive seals.
  • Throttle Bushing – increased size of the throttle or “disaster bushing”.  When seal failures do occur, the process can be directed to the drain port for added safety, and to provide an improved housekeeping advantage.
  • Enhanced Barrier Circulation – groove machined in the gland to assist with barrier fluid circulation.  The added circulation further helps to keep the seal faces clean and operating cooler.
  • Thicker Bellows – manufactured bellows thickest in the industry. Available in sizes up to 3.750″.
  • Improved Set Screw Material – made from 17-4 H900 stainless steel to insure a positive bite into the sleeve/shaft, thus reducing slippage and galling of the drive collar.  This upgrade also makes it easier to remove the seal if required.

ISC2 seals meet all major international standards and ISC2-682 seals help customers align their standardization programs with the sealing industry’s most comprehensive best-practice standard: API 682/ISO 21049.

related information:  Flowserve Pumps
related information:  Durco Pumps
related information:  Pump Repair

Tim Davis
1900 Jetway Blvd
Columbus, OH 43219