Planned and Systematic Measures in the Quality Assurance Process


LEKO Fans will supply the world’s largest black liquor evaporator in South Africa with two dual turbo blower sets, two lines in parallel, with a combined engine power of 16 MW and an evaporation capacity of 400 tonnes per hour. In addition to spare parts, this very extensive project also includes commissioning services and warranty testing.

LEKO Fans Quality Control Process Starts at the Drawing Board

Starting from the definition of customer needs, quality control includes all planned and systematic measures to ensure the product meets all its quality requirements. As the manufacturer is responsible for the conformity of the product with the EU Pressure Equipment Directive, as well as legislation and regulations, the inspections and the final evaluation shall be carried out by a knowledgeable third party to maximize reliability. DEKRA Industrial Oy is an inspectorate accredited by the Finnish Accreditation Service FINAS and acts as an inspection body approved by the Finnish Safety and Chemicals Agency Tukes as an inspector of pressure equipment under national law. The Ministry of Economic Affairs and Employment of Finland has certified with the European Parliament and the Council (EU) that DEKRA is a Notified Body 0875 in accordance with the Pressure Equipment Directive PED 2014/68/EU. In accordance with the necessary assessment procedure, DEKRA will carry out a conformity assessment for the product by approving the plan, verifying the quality material required for the preparation of the product and reviewing the product at a pressure test.

In accordance with the high requirement level of the application, the blower material is made of extremely corrosion-resistant and acid-proof duplex steel. Duplex stainless steels are suitable for many corrosive environments. Lehtosen Konepaja uses high-quality materials, and their partner in procurement is Outokumpu, which specializes in steel production.

Water Pressure Test Ensures Compliance with Design and Manufacturing Values

For each turbo blower unit, DEKRA monitors a water pressure test to verify that the manufacturing process has been carried out according to the plan. The pressure test reveals, among other things, any possible leak points. During the pressure test, the product must prove to be durable and shape-preserving. The manufacturer is also required to carry out welding quality monitoring in the manufacture of pressure equipment. In order to meet the requirements, the manufacturer must perform coordinated welding and use only certified welders. In the manufacture of the product, weldability in particular must be taken into account already at the time of designing the product and selecting the materials.

LEKO Fans turbo blowers are an exceptional target for pressure testing. Testing was carried out in accordance with PED regulations to meet the requirements of the customer and the product’s final destination. The audit was focused on the visual quality of the product and the quality of welding. The performance of the pressure test was documented in the test protocol and the certification body’s Certificate of Conformity allows the manufacturer to CE mark the product.

Lehtosen Konepaja Quality Assurance Also with PMI Measurement

The quality assurance of Lehtosen Konepaja covers the entire manufacturing process from the material selection to the welding quality requirements and assembly. Systematic quality control is essential for all metalworking, especially for checking safety-critical positive materials. The PMI measurement distinguishes pure metals from alloys quickly and accurately. All parts and materials associated with the same process must be tested to ensure the best possible quality for the customer and to prevent problematic situations caused by the wrong metal alloy.

The PMI measurement was carried out by Kiwa Inspecta, which operates as a control body under several EU directives and national legislation. The supplied PMI measurement confirmed that the turbo blower materials were duplex steel, and the measurement technology also allowed the checking of a small/narrow point, e.g. the weld seam. Inspecta also examines the technical documentation submitted by the customer. In module G, the Pressure Equipment Directive does not directly require a separate certificate of the examination of the plan, but in accordance with the generally accepted practices in the field, Inspecta provides an opinion on the acceptability of the design data and other technical documentation.