Howden Thomassen compressor regrout and resin injection

In Spring 2017, Alphatec Engineering collaborated with BayerNoil at the Neustadt Refinery in Bayern, Germany, to restore the foundation of a Howden Thomassen C.20-4 compressor—an essential asset powered by a 950 kW SMIT electric motor.

The project focused on addressing foundation weaknesses, including cold joints, oil penetration, and inadequate anchoring, which had compromised the compressor’s performance.

Features

Client

Bayernoil Raffinerie GmbH

Final user

Bayernoil Raffinerie GmbH

Project

Foundation Pressure Injection Repair, Realignment, Regrout

Equipment

Thomassen Compressor C.20-4 type

Work period

18–26 February 2017

Location

Neustadt ad der Donau, Bayern, Germany

01 Challenges and Objectives

The original foundation—installed in the early seventies—was plagued by multiple horizontal cold joints and areas of oil flow-out that caused anchor bolt looseness and insufficient clamping.

These issues endangered the stability of the compressor and risked further mechanical damage. The primary objective was to reinforce the foundation using advanced resin injection and regrouting techniques, ensuring both secure anchorage and improved load distribution.

02 Technical Approach and Procedure

To restore the foundation integrity, our team implemented a comprehensive repair strategy:

Preparation and Protection
The technical team prepared the compressor by installing dust and heat protective sheets, dismantling the motor for revision, and removing any obstructing piping and wiring.

Resin Injection and Grout Removal
We drilled 16 holes (65 mm in diameter and 2.5 to 4.0 metres deep) in the foundation to enable pressure injection of Alphatec® 342 resin. This step sealed cold joints and eliminated oil ingress. Concurrently, old cementitious grout was chipped away from the affected areas around the compressor plinth.

Regrouting and Realignment
After thorough surface cleaning—including grinding, wire brushing, and solvent cleaning—the team applied Alphatec® 800 epoxy grout to restore the damaged base. Anchor bolts were reinstalled on steel sleeves, enhanced by square shim plates under the levelling screws to ensure effective clamping. A pneumatic plunger pump was used to inject the resin under pressures up to 300 bar, further stabilizing the foundation.

03 Results

These targeted measures corrected the foundation’s structural deficiencies, reinstated proper alignment, and secured the anchoring system.

The combined resin injection and regrouting solution not only improved the operational stability of the Howden Thomassen compressor but also safeguarded the equipment against future mechanical issues.