Case Histories

PTFE-Lined Piping

Service: Caustic, chlorine, and chlorinated organics flowing through PTFE lined piping at ambient temperature

Problem

Expanded PTFE gaskets were flimsy and difficult to install. The gaskets crept and the liners relaxed, which led to leaks. Spring washers were required to keep a seal on the ePTFE gaskets and PTFE-lined piping.

Significance

Difficult installation, cycling, and piping and gasket relaxation caused unacceptable leakage, which led to potential fines and tighter monitoring by the EPA.

Solution

The high maintained contact stress of the spring inserted PITA® gasket overcomes and compensates for PTFE Creep, eliminating leakage and ensuring safety and environmental compliance.

For us, the major advantage (of the PITA® gasket) comes from the corrugated insert keeping the joint loaded even as the PTFE liner relaxes over the life of the connection.

- Engineer, Chemical Plant

General Process Piping

Service: Ethyl Chloride Autoclave. 340 psig operating at 270˚F

Problem

The customer was using compressed non-asbestos gasketing in this application. A significant blow-out failure led to the search for a more reliable blow-out resistant gasket.

Significance

Failure and leakage led to a significant fine from the EPA and triggered tighter monitoring requirements. Enhanced employee safety and overall connection reliability were identified as key factors in the search for an improved gasketing material. VSP engineers were called upon to assist with identifying and qualifying the improved material/design.

Solution

VSP engineers qualified the LoadLock™ material in a unique OPRA™ design to ensure optimal maintained gasket stress, blow-out resistance, and provide equipment specific assembly procedure and torque.

Paper Mill

Service: Green Liquor in clarifier operating at 212˚F under atmospheric pressure

Problem

Improper bolting and installation led to leakage, which required disassembly/reassembly of the manway. A great deal of time was lost due to mechanics collecting needed parts and components.

Significance

Manway re-assembly was a high-cost, labor-intensive project that resulted in environmental issues and the loss of expensive product.

Solution

VSP Torq-Kit™ provided proper bolting, torque, and installation recommendations in one box with all the rework components. This contributed to significant time and material cost savings.

Precipitator Mix Tank Manway Gasket

Service: Black Liquor kept at 175˚F under atmospheric pressure

Problem

Thin, under-bolted API 650 manway flanges cannot develop sufficient gasket stress for a reliable seal with standard full-face gaskets. Ring gaskets were used which allowed the flanges to bend/warp and prevent uniform, proper gasket compression resulting in chronic leaks.

Significance

Improper bolting, installation and gasketing - of both material and size - led to leakage, loss of expensive product and environmental issues. Leakage required costly disassembly and reassembly of the manway.

Solution

ePTFE Gore GR gaskets were designed for the flanges using VSP’s patented OPRA™ reduced area design technology. The resulting gaskets achieved required compression during assembly, without flange bending/warping, and provided long term connection reliability and NO LEAKAGE.

Chemical Plant Process piping

Service: Chlorinated organics at elevated temperatures flowing through process piping

Problem

Due to higher temperatures causing gasket blowouts, PTFE gaskets were replaced by traditional spiral wound gaskets. However, many of the flanges were slip on or lap joint with available bolt loads too low to properly seat the Class 150 spiral wound gaskets. This solution was not reliable.

Significance

PTFE gaskets required retorquing and had problematic blowouts causing process downtime and excessive maintenance. The existing pipe network could not accommodate traditional spiral wounds, especially those with inner rings.

Solution

Low stress to seal AB-326™ anti-buckling spiral wound gaskets were installed eliminating gasket failure and significantly reducing production loss and maintenance time.

Chemical Terminal

Service: Tergitol™ solutions, amines, alcohols, and acetates flowing through hose flanges at 40 PSI operating between ambient to 130˚F

Problem

PTFE gaskets are initially selected solely for chemical resistance without any awareness of the material's mechanical/thermal (creep) limitations. Frequent retorquing of the flanges was required to minimize leakage.

Significance

Leakage of these hazardous chemicals created personnel safety, leak containment/mitigation and environmental issues leading to tighter monitoring requirements by the EPA in addition to potential fines.

Solution

Due to its broad chemical resistance, low stress to seal, spring-energized core and zero leakages, VSP’s PITA® gasket was selected. The superior torque retention eliminated the creep the customer was experiencing and stopped the leakage.

The PITA® gasket is the best gasket we have ever used. We are always able to get a seal and never have to go back and retorque the gasket after initial installation

-Maintenance Supervisor, Chemical Plant