Tag Archives: mechanical seal

Case Study: A Single Mechanical Seal, But Twice As Safe Under High Pressure

Mechanical Seal SHVI and Plan 66A for Unmanned Pump Station of an Oil Pipeline

A well-known Canadian operator of an oil pipeline commissioned EagleBurgmann to develop a sealing solution for crude oil pumps. The requirement: It needed to be a single seal that was just as safe as a double seal with buffer pressure system. In addition, the sealing solution was not to be designed for only one pump type but should be installed in various pumps of one station.

SHVI Operating Conditions

The operating parameters were quite extensive: The seal needed to be suitable for a pressure range from 2.5 bar (36 PSI) to 99 bar (1,436 PSI) as well as for shaft diameters from 115 mm to 155 mm (4.53’’ to 6.10’’). Since the pump stations are operated unmanned, the seal must operate without an additional supply system. To protect the environment and personnel, however, the seal housing must not leak if the seal fails unexpectedly.

The solution: Mechanical seal SHVI from EagleBurgmann

These requirements were best met by the SHV series which has proven itself thousands of times over in crude oil pumps and MOL pumps (MOL: Main Oil Line) of all types worldwide for many years. For the Canadian customer, EagleBurgmann developed the SHVI sealing variant with loosely inserted seal face specifically for the high-pressure range. The seal face is single, but is twice as safe under high pressure and is designed such that it always builds a parallel sealing gap with the stationary seat. The deformation behavior of the seal  face was optimized for use in crude oil pumps so that the seal operates reliably even under very high pressures, sliding velocities and temperatures as well as pressure and temperature fluctuations.

Silicon CarbideEagleBurgmann selected a special quality of the silicon carbide material to be used in the pumps of the pipeline operator. This provides the seal face with particularly good emergency running properties and tolerance for partial dry running. In addition, the sliding faces have extremely precisely ground grooves which allow the seal face to be lifted quickly even in the low pressure range and contribute to stable operation in a wide pressure range.

Safety: Optimized API Plan 66A

Plan 66A, which has been available since introduction of API 682 4th Edition, was the obvious choice for the safety concept. Accordingly, the seal housing contains two throttles, and the seal chamber is connected to a pressure transmitter.

SHVI PipelineEagleBurgmann optimized the plan and uses a special inner, floating  throttle. This can withstand a product pressure of 99 bar (1,440 PSI) in an emergency. The pressure transmitter detects pressure changes in the seal chamber and signals an alarm if certain values are exceeded. At the same time, the seal leakage accumulated under low pressure is discharged to a central collection system in the pump station.

Test and Acceptance

The SHVI seal and the optimized Plan 66A were subjected to dynamic and static tests individually and together on EagleBurgmann test benches. The constant and reliable sealing performance in all operating states and the safe function of Plan 66A in the event of a fault provided impressive results. The required system safety was provided at all times.

The new concept of the SHVI single seal with optimized Plan 66A is economical, modular, reliable in operation, and offers the safety of a double seal.

There are plans to convert further pumps of the pipeline operator. The new concept of the SHVI single seal with optimized Plan 66A is economical, modular, reliable in operation and offers the safety of a double seal. For other customers as well, this type of seal has since proven itself in MOL pumps for several thousand operating hours.


To Learn More about the SHV series of mechanical seals, contact us today at 1-800-822-4063 or click the button below.

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H75VN Mechanical Seal for Cumene Pump Station

Retrofitting a Pump with an EagleBurgmann H75VN

Cumene, the common name for isopropylbenzene, is an aromatic hydrocarbon and a colorless liquid under atmospheric conditions with a characteristic smell. It is a component of crude oil and refined fuels and is mainly used in the production of phenol.

The Problem

Ineos in Gladbeck and Degussa in Marl, both located in Germany, are supplied with cumene by a pipeline. The pump station for this pipeline is situated inside the chemical industry park in Marl and is operated by Degussa Infracor. Cumene is classified as hazardous to the environment, so the “TA-Luft” directive (German Clean Air Directive) has to be considered for any sealing solution.

Originally, the pump was equipped with a Flowserve mechanical seal type EUROPAC 613/663 in tandem arrangement. With this seal, the required maximum temperature of the supply medium of 104˚F (40°C) was always exceeded and the seal was continuously squeaking during operation.

Operating Conditions

  • Medium: Cumene
  • Operating temperature: 41˚F – 122˚F (5 – 50˚C)
  • Operating pressure at seal: 17.4 – 34.8 psi (1.2 – 2.4 barg)
  • Pump: Centrifugal pump, type MC 80-260/62
  • Pump manufacturer: Sulzer
  • Speed: 2,975 rpm
  • Seals include materials: H75VN/80-FTA5, AQ1KMG – AQ1KMG
  • Mode of operation: Plan 11 and Plan 52 according to API 682
  • Supply system: TS 2000/M051-A1, operation under atmospheric pressure

The EagleBurgmann Solutionpicture of the H75VN

The critical points of this application are the poor lubrication properties and the low heat capacity of the process medium. The engineered EagleBurgmann H75N mechanical dual seal in tandem arrangement was selected and retrofitted to the pump.

Technical features of the EagleBurgmann H75VN seal:

  • Cartridge unit, easy to install
  • Certified according to API 682/ISO 21049 for the application in flashing hydrocarbons. Meets the requirements for low emission seals based on STLE-limit values
  • Counter-rotating pumping screw to support the circulation of the buffer medium to ensure an optimal cooling and lubrication of the mechanical seal
  • Plan 11 and 52 with multi-point injection: the buffer medium is divided into several sub-currents that are directed towards the sliding face at relatively high flow velocities, improving heat removal from the mechanical seal
  • Self-closing: the seal will remain closed and will keep the full functionality even in situations of pressure reversal or failure of the supply system
  • Perfluoroelastomers due to the chemical resistance

Conclusion

The EagleBurgmann H75VN meets all requirements of the operator regarding the maximum buffer fluid temperature of 104˚F (40°C), and the squeaking of the seal was eliminated. The mechanical seals have been successfully in operation since the beginning of 2006 and have been running to the full satisfaction of the customer, with further pumps retrofitted currently. Additionally, the EagleBurgmann H75VN mechanical seal is now specified as standard for pipeline pumps.


Gallagher Fluid Seals is an exclusive distributor of EagleBurgmann. For more information about custom solutions or mechanical seals, contact our engineering department, or call 800-822-4063.