Proprietary Innovation

Proprietary Prowess in Screw Plug Heat Exchangers: Unleashing Next-Level Efficiency

The 1992 explosion and fire of a High-Pressure Breech Lock Heat Exchanger in Japan, along with other global failures, reduced trust in the Breech Lock design. Tema India conducted research to enhance its safety and reliability.

Identifying the problem

FEA analysis revealed issues with uneven thermal expansion causing stress, leading to bell mouthing in the threads, reducing shear area, and potentially causing an explosion. Thread galling can also occur due to plug displacement, making parts seize and creating a seal lock.

Finding the solution

Bending stress can be three times the longitudinal stress in the undercut area, leading to radial displacement and channel dilation. To prevent this and reduce shear area, the threaded region’s wall thickness needs to be increased. Extensive analysis showed the need for added steel in this area, and testing confirmed it reduces distortion and facilitates plug removal.


Shrink Ring Screw Plug Heat Exchangers(SRXTM)

Our Shrink Ring Screw Plug Heat Exchangers (SRXTM) are known all over the world for patented Shrink Ring technology used for high pressure, high temperature, corrosive, hazardous and dirty service applications in Hydrocrackers, Hydrotreaters and Desulphurization plants of a refinery.

It is designed and fabricated as per the ASME Code. In addition, analysis is carried out to determine the differential thermal expansion between the channel wall and channel internals to counter additional stresses on the gasket, leading to its premature failure.

Additionally, measures are implemented in the exchanger design to mitigate operational stresses on the threaded portion at the end of the channel. This involves incorporating a shrink-fit steel ring to prevent radial flaring, a phenomenon referred to as bell-mouthing.

We manufacture Shrink Ring Screw Plug Heat Exchangers in two variants:


Presentation of technical papers at ASME PVP Conference

In 2016, Tema India’s Haresh Sippy presented a pioneering paper on screw-plug design at the 50th ASME PVP Conference in Canada. The paper tackled critical issues with Screw Plug Heat Exchangers and offered practical solutions. It is available for download on the ASME website, with copyrights assigned to ASME.

These findings have influenced global heat exchanger design, enabling refiners to retrofit and refurbish exchangers during routine turnarounds and meet emission standards like US EPA Tier 4/ EURO VI.

In 2017, ASME accepted another paper titled “Design of Threaded Closures for High-Pressure Screw Plug Heat Exchangers(SRXTM) Designed to ASME Section VIII Division 2.” It is expected to be available for download from the ASME website by December 2017.


Innovative Solutions

Tema India has several innovative solutions: