A process generally undergoes initial development within a laboratory and is then made production ready in pilot or mini plants. During this scale-up, a range of different problems can emerge, e.g., in the way temperatures behave. In a laboratory, a process may be endothermic but becomes exothermic in production. How pumps behave in relation to peripheral equipment can change under full-scale production conditions, Sven Borghoff describes a coordinated pump and drive concept which makes scaling up easier.
Dosing pumps with multifunctional extensions for different pump types often used in laboratories generally have no particularly high temperature or pumping ranges. However, when scaling up, these aspects take on major significance. Gather uses its magnetic-driven pumps (Fig. 1) here. They are available in such a broad range that when scaling up from the laboratory to production via a mini or pilot plant, the pumping and control technology can be retained. The company cooperates with the chemical industry, institutes and universities to make process development from initial laboratory trials through to production easier.
Requirements on pumps vary widely. A new product undergoes development within a laboratory and the initial production capabilities are tested using small quantities. The new concept is then made production ready under real conditions within mini plants. The scale-up of the new chemical production process then takes place in the production plant. 1:8000 scale-ups are today the norm. The shift from laboratory to mini plant and then to production has a multitude of obstacles which need to be overcome with the equipment and instruments being used. To apply modern measurement and control technology for small quantities requires, for example, powerful pumps that are also able to pump, pulsation-free, the smallest quantities of material thereby ensuring precision and reproducible metering. Such pumps also need to be made of chemically and thermally resistant materials such as stainless steel, Hastelloy, titanium or other special alloys.
The drive systems being used (including speed control) must be universally applicable and easy to integrate into measurement and control systems. The pump system must also fulfil additional needs in the lab, mini plant and production.
- In laboratories, maximum flexibility in applying different pump systems (displacement and turbine pumps) is required.
- In mini plants, hermetically sealed pumps are needed, especially in the chemicals industry, in order to prevent any health hazard. These pumps need to convey small amounts, pulsation-free, across the largest possible measuring ranges and must also be capable of pumping hot solvents for system cleaning. Their service lives must be that of process pumps to prevent production downtimes because, ultimately, small-scale production under real conditions is taking place – something that should never be forgotten. The pumps require integration within a control loop (e.g. flowmeter) for better control and evaluation. Measurement and control technology in combination with drive and control technology need to be depicted as for production to enable time and costs to be saved.
- The demands on pump systems in production plants are similar to those in the mini plants. However, process parameters are relatively fixed so a high level of flexibility is no longer necessary. Service life and easy maintenance are major issues so as to avoid production downtimes. Furthermore, pump operation takes place here within a control loop for inclusion in production planning to ensure end-product quality documentation and a high level of automation.
Although these demands may at first seem very different, it is soon evident that they can be reduced down to two core needs: non-pulsating pumping of chemical process pumps; and multifunctional drive technology.
The first need is quick to satisfy. All Gather pumps (turbine and gear pumps) have non-pulsating pumping characteristics and are hermetically sealed through magnetic coupling (compliant to clean air guidelines (TA-Luft)). However, non-pulsating does not always mean non-pulsating. A distinction should be made between oscillation and pulsation. Gear pumps oscillate and are always non-pulsating because they do not generate distinct pulsations as in simple diaphragm or piston pumps. The term pulsation is often used when oscillation is actually meant.
How minimal a Gather gear pump oscillates is shown by the values recorded using piezo quartz (Fig. 2). Oscillations are under 10 mbar and are practically imperceptible to flowmeters at this size and frequency. This significantly increases dosing reliability because there is also no overall strong oscillation of the loop control. Gather pumps are robustly constructed to guarantee durability and reliability.
Different drive technologies are available that are designed specifically for laboratories, pilot plants or production. Overarching models are also available. The basis is the tried and tested LAB drive and control series. LAB 10 is the classical compact laboratory drive (Fig. 3). It is a basic DC servo-motor installed within a housing with speeds being adjusted either with a potentiometer or external setpoint (010 V, 020 mA). It can be used to drive both gear and turbine pumps.
The LAB 20 and LAB 22 controllers can be universally applied from laboratories through to production. Because these essentially concern frequency-converter supported drive models, programming parameters can be transferred to plant concepts with explosive atmospheres (Atex) and/or to specific user control standards.
The institutes, universities and industrial enterprises working together with Gather praise the major time savings that are possible by using Gather products to take a process from the laboratory through to the end production plant. The modular-based pump systems enable simple adaptation to changing pump, temperature and pressure conditions. The especially time-consuming adaptation of control parameters to coordinate systems at the different development stages then becomes practically unnecessary.
Detailed overall pump concepts including drive techniques therefore not only help reduce costs but are also faster at getting products ready for market.