Faced with extreme temperatures, hazardous substances and high pressure, if processes in the chemical industry are not carried out safely, the consequences are severe. In the worst-case, accidents and explosions can occur that endanger human life and cause serious injuries to employees. Extending beyond the hazards in the workplace, the quality of the manufactured products must be ensured. If processes are not stable, deviations from the product specifications can occur. The result: inferior or dangerous end products. However, it is not just people who are at risk due to unsafe processes – the environment is too. If the equipment leaks, chemical substances that cause environmental damage can escape.
Wherever chemical processes are involved, to protect people and the environment, the focus is always on process reliability. Pumps are an integral part of the process and they play a particularly important role. They bear a responsibility; they ensure that the process runs smoothly. For example, pumps are used to convey liquids such as chemical solutions.
Due to the associated high risks, the chemical industry imposes special requirements on the process pumps of the systems. Correct selection, installation, maintenance and monitoring make it possible to carry out chemical processes safely and efficiently. The condition, i.e. the quality, of the pumps must also meet these special requirements.
DURABLE MATERIALS
“From the material to the design and the accessibility for repairs, chemical pumps must function flawlessly in practical application,” says Stefan Anstöter, product manager at Timmer GmbH (above). “Here, there is no room for error. That’s why we have optimised our pumps so that they meet – and exceed – all industry requirements.” Everything starts with deliberate use of suitable pump materials. For example, stainless steel, which has proven to be effective in other industries, is often not suitable for chemical applications because it is subject to attack by alkalis and acids. Instead, the pumps in the timCHEM product line are equipped with a plastic housing. The polytetrafluoroethylene (PTFE) used is compatible with the chemicals that are used.
The optimum choice of materials must be considered holistically and optimised even at the level of the individual pump components. For instance, threaded sleeves that are screwed into the plastic housing are common on the market. External influences such as temperature fluctuations change the shape of the material and the housing then tends to leak at the connections. Timmer uses a design for its pumps that connects the highly-resistant plastic components that are in contact with media, by means of tie rods. The force exerted by the tie rods is distributed by the large-area reinforcement plates – a measure that minimises deformation of the plastic.
To ensure maximum protection, stainless steel sheets encompass the pump and provide stability for the entire construction. However, in the interior of the pump, metal does not come into contact with the medium. Plastic – and plastic only – which has been tested for resistance, completely encloses the processed medium.
The material is FDA-compliant and thus it is food-safe. This is a property, which at first glance may not seem relevant in the chemical industry. However, in this regard it is worth taking a look behind the scenes. The chemical industry is involved in the manufacture of pharmaceutical products. Even if the end product – such as a common pain-relief tablet – does not come into contact with the chemical pump, the specific substances that make up the pain-relief tablet pass through the chemical pump in various processes. Thus, with Timmer chemical pumps these upstream products only come into contact with materials that are FDA-compliant.
SEAL OF APPROVAL
Optimal sealing of a pump is a major aspect of process reliability. It is a characteristic that plays a central role in product development at Timmer. In this regard, the design follows a simple rule: The fewer sealing surfaces, the fewer possibilities of a leak. Consequently, Timmer’s chemical pumps have only four sealing points. In comparison other pumps are sealed at up to twelve points in the media section.
Selected components are safe, leak-proof and can also be replaced quickly if required. The design also enables fast and easy on-site service. In this area, less is more, because the number of wear parts has been minimised, which reduces maintenance effort and costs. “Although design effort and use of high-quality materials initially result in higher investment costs, these costs quickly pay for themselves in practice in the form of longer service life and less maintenance effort,” reasons Anstöter. “This factor is something that users in the chemical industry really appreciate. Other industries often focus on cost-optimised solutions. However, for the chemical industry, process reliability is the top priority.”
In addition to reliable sealing and durable pump materials, there is yet another factor that plays an important role in the chemical industry: explosion protection. The ATEX (atmosphères explosibles) directive specifies the product requirements for explosion protection. Timmer designs and manufactures chemical pumps that meet the requirements stipulated in this directive and are therefore ATEX-compliant – an important and necessary characteristic depending on the system environment.
EASY ACCESS FOR REPAIRS
If a pump should fail, fast repair is essential in the chemical industry. In the worst-case, potentially hazardous substances will escape leading to health issues for humans and a negative impact on the environment. In addition, long downtimes are always associated with economic losses for users. Proactive maintenance and fast repair enable companies to identify potential problems early on and rectify them before they result in major damage.
To this end, Timmer chemical pumps come factory-standard with an intelligent sensor for condition monitoring. The sensor can be integrated directly into the user’s process control system. Integrated in a process control system the sensor shows the real-time status of the pump and by means of an additional system, immediately sounds an alarm should an error occur. The company decides how the pump should be integrated into the system and what data it should display. If an error message occurs and if repairs are required, service technicians benefit from the easy accessibility offered by the pumps. For example, valve balls and valve cages can be replaced without dismounting the side covers. Use of special tools is not necessary.
The heart of the pump, a ceramic latching valve, ensures smooth operation. All of the valve’s friction pairs are made of ceramics in conjunction with precision-ground, high-performance plastics. The result is minimum wear in the valve itself. To increase the service life of the diaphragms, Timmer relies on the short-stroke principle. The reduced stroke path provides long-term protection of the diaphragm. “As simple as the design of our chemical pumps is, the interaction of the specific components is quite complex,” confirms Anstöter.