ACHEMA Report on Trends in Pumps / Fittings / Seals

Some time ago, the market leaders began to focus on cost-of-ownership as a selling point. Practical experience has shown that this is an arduous task. When dealing with their customers, manufacturers are continually confronted with the situation that the purchasing, engineering and maintenance functions have diverging interests. Purchasing looks at the price, plant engineering is annoyed that the technology is not 100 percent satisfactory, and the maintenance crew asks itself in amazement why a different pump, fitting or seal is not used despite the fact that faults keep occurring in the same place.

Can this actually be the real situation in the industry? It certainly can in the view of innovative manufacturers, who attempt to pass on high development costs. They claim that the crux of the matter lies in the lack of an interdisciplinary approach. With most operators, no one feels responsible for "moving media X from A to B". Everyone has their eyes fixed on their own cost center.

At ACHEMA 2003 in Frankfurt/M, manufacturers and users will have ample opportunity to hold intensive discussions on the topic of life cycle costs. The result will hopefully be solutions that deliver more efficient facilities. In the unambiguous words of one industry observer: "It's not just the pump – look at the system, stupid!“

Pumps: the focus is back on a unit that does not leak

German centrifugal pump manufacturers saw their business increase in the first half of 2002, exporting 3.3% more than in the same period in the previous year. The situation has deteriorated slightly for positive-displacement pumps (oscillating positive-displacement pumps -1.2% and rotating positive-displacement pumps -3.8%). These results underline the fact that the centrifugal pump market is showing moderate growth following a period of stagnation in recent years. A study conducted by Frost & Sullivan predicts turnover in Europe to increase from $US 2.87 billion in 2000 to $US 3.34 billion in 2006, which equates to an average annual growth rate of 2.5 percent.

Increasing requirements are being placed on centrifugal pumps, leading to strong demand for innovative high-tech products. This is also having a positive impact on quality standards. It is not surprising that sealless pumps show the highest growth rates: Given the enormous pressure and temperatures that are sometimes present in process technology applications as well the toxicity and explosive potential of pumping media, hermetically sealed drives such as canned motors and magnetic couplings already play a very important role in today's chemical process technology. Operators claim that the use of non-leaking aggregates is expected to increase in the future. There is still significant potential to push forward the development of canned motors and magnetic drives and possibly combine the two technologies. More stringent environmental regulations (such as the German Clean Air Act) and an expanded range of applications are the primary reasons why experts expect very high growth rates for sealless pumps. Many observers expect quantum leaps in innovation in the not too distant future. It will be interesting to see what new products the manufacturers will present at ACHEMA 2003.

Plain bearings in hermetically sealed centrifugal pumps are lubricated and cooled by the pumping medium. This can lead to problems in practical application, such as dry running or vaporization of the medium. Magnetic rotor bearings represent a possible solution to the problem, at least for niche applications. One manufacturer claims that by using a self-bearing disk-type motor, it can build a very simple centrifugal pump with a magnetically free-floating impeller. The company explains that a single motor/bearing unit provides both the drive and magnetic bearing function and is capable of magnetically stabilizing the spatial degrees of freedom of the impeller without direct contact with the walls of the pump housing. Pumps of this type move media in biotechnology and ultra-pure chemical applications as well as CMP slurries in the semiconductor industries. However, their performance is limited to low drive power of less than 1 kW.

The increasing importance of attractive service strategies

There is also intense discussion in the industry on the topic of service/maintenance. There is an increasing awareness that condition-oriented maintenance and repair can significantly increase MTBF (mean time between failure), reduce downtime and decrease cost. It is of primary importance that the operator checks from time to time whether the design parameters are still correct (maybe they never were). The focus should be on a detailed analysis of faults, ranging from non-matched materials and a non-optimal operating point to an unsuitable mechanical seal.

The "total pumping concept" is now being offered as well as a service package. A manufacturer of wastewater pumps covers the entire operational performance of pump stations and provides total 24-hour monitoring. The package includes assurance of operational reliability, repair, maintenance, cleaning, refurbishment and operating documentation over a period of 10 to 20 years. The operator has a choice of various service levels tailored to meet his/her individual needs. Benefits include predictable levels of expenditure in the long term, constant monitoring of the facility and permanent operational optimization.

The trend towards integrating intelligence in the shape of electronics directly at the pump remains intact. Sensors monitor the pumps around the clock and send out an alarm in time if a fault is about to occur. In some cases, the alarm is raised in a conventional manner using signal contacts, which are connected to higher-level control circuits. Using a digital field bus appears to have advantages, because a greater volume of more detailed information can be sent. If a variable rotational speed drive is involved, action can be taken to address impending faults and avoid malfunctions. Concepts for remote monitoring and diagnosis of aggregates, including monitoring via the Internet, are becoming increasingly important in this context. A number of manufacturers will be presenting service products of this type (including teleservice) at ACHEMA 2003.

Feasible early recognition of faults begins to take shape

As pumps become more expensive and as the complexity of the circulation system in which they operate increases, there is a greater need to continually record and monitor the condition of the pumps. Because the pumps react to changes in a system, they can act as an indicator of unplanned conditions in the system. Damaged plain bearings, for example, often result from gas penetrating into the pumping medium. To increase system availability, it is important to understand at the outset the relationship between system conditions and the corresponding reaction in the pump. This was the starting point for intelligent state monitoring of centrifugal pumps that only use a minimum of sensor mechanisms. One analysis of failure statistics showed that two or three sensors are sufficient to properly monitor a pump and also to provide a significant amount of diagnostic capability. The sensors are used to detect dry running, to measure bearing temperature and above all to detect vibration.

The frequency spectrum, which describes the sound of the pump, contains a wealth of information. New diagnostic systems relieve personnel from the task of routinely checking the pumps, leaving them free to concentrate on operation and maintenance of the system. Initial field tests have confirmed the potential and functionality of modern diagnostic methods.

Seals: the need to fine tune materials

High pressure, temperatures ranging between -40°C and +300°C, together with ambient conditions such as humidity or heavy levels of contamination are typical in process technology applications. Other factors include strong vibration, pressure peaks, lateral forces, etc. To guarantee functional reliability across the entire range of operational conditions, materials and geometry in sealing systems must be very carefully matched.

Users, however, are no longer satisfied with the reliable command and control of forces. They expect fast, exact predictions about the long-term behavior of sealing elements. On-going basic research is needed to meet these demands. Knowledge of tribological processes is continually increasing. FEM (finite elements method) is being used in the design phase to optimize seal geometry calculations to achieve the desired results in a shorter period of time.

Suppliers of sealing systems are not only faced with meeting the challenge of conforming to legal requirements such as the new version of the German Clean Air Act. They also have to offer their customers economical solutions. Favorable investment costs, long service life and easy access for maintenance are high on the priority list. There is another development that is receiving increased attention. Whereas the focus for a long time was on increasing sophistication in seal geometry, today part of the emphasis is being placed on optimization of materials. Fine-tuning is at the forefront of this effort. Materials are trimmed exactly to match the requirements of a particular application. There are good reasons for this. Today, for example, there are reactors available for the chemical synthesis of small material volumes together with appropriately fine-tuned process management systems. This eliminates the dependency of seal manufacturers on what products the large chemical companies offer.

Experts agree that despite the considerable success of sealless pumps in less demanding pumping applications, the mechanical seal will retain its position of importance. As with pumps, new sensor technology designed to help monitor the condition of dynamic seals is expected to create new application opportunities and also reduce costs. In the past, a mechanical seal was not replaced until it failed. Where safety was an issue or where the potential risk to operational reliability was high, the seal was replaced at regular intervals. Modular diagnosis systems now provide the operator with a continuous stream of information about the state of his/her seals. A seal is not replaced until there is a real need to do so.

What are the inputs from the maintenance engineer? What is on his/her wish list? Because working on seals often involves manual labor, seals should have a higher fault tolerance. Also, it might be better if the facing for rotary shaft seals were to be supplied along with the seals, as is the case with mechanical seals. The facing often proves to be a critical component in many applications.

Fittings: a growing number of automated control fittings

The oil and gas industry represents the largest customer base for industrial fittings in 2002 with a market share of 32.6%. The chemical and petrochemical industry is the second largest sector at 19.9%. The German Engineering Federation has reported that the approximately 170 German manufacturers produced industrial fittings with a value of 2.06 billion Euro in 2001, an increase of 2% compared to the previous year. A 5% increase in exports lifted the industry's export quota to 65% (the direct and indirect export share of production output).

These figures lend support to an industry analysis performed by Frost & Sullivan, which views European producers as holding a firm position in the market for industrial fittings and actuators for the process industry. Sales on the European market are expected to increase annually by 2.2%, from $US 3.53 billion in 2001 to $US 4.1 billion in 2008. Factors such as the increased use of natural gas should stimulate investment in the oil and gas industry, which is the largest application sector. Intelligent fittings equipped with actuators, which are an integral part of all modern fittings systems, together with field bus networks and online systems, will provide impetus for continued growth. A large installed base of fittings and actuators guarantees strong demand for spare parts as well as replacement and upgrade products, and this is also a significant factor in total sales volumes.

The medium determines the fitting design

Materials that are normally transported in the industry through pipelines (gas, process water, acid/alkaline solutions, powder and granulate) as well as operating temperatures determine to a large extent a fitting's design and the materials used to make fittings. If aggressive media are used, components that come into contact with the product must have good corrosion resistance. They must also be able to withstand the operating pressures present in the system. The fittings must prevent leaks within the flow system and above all to the outside environment (chemical, petrochemical and nuclear power applications).

Whether a valve, a butterfly valve, a ball valve or a slide gate valve should be used depends primarily on the type of pumping medium and operating conditions. There are other, higher-order factors to be considered when automation is being introduced for industrial valves (existing drive standards, available interfaces and bus systems, control technology, etc.).

An overall perspective as well as knowledge about individual characteristics are needed to choose the "right" valve design, since the valve is nearly always a component in a complete system. Actuators, which were developed during the introduction of automation in the user industries, are replacing the levers and handwheels that were used in the past to operate the valves. There are two different requirement profiles to consider when automation is being applied to valves. There is pure on/off control, where the valve must only to be moved to one of the end stop positions. In contrast to this, there is variable control, where a nominal value is used to monitor the change of position of the valve in the pipeline flow.

The proportion of automated industrial valves has doubled in recent years. The ratio of manual valves to automatic valves has already reached about the 70/30 level. Experts expect that in process technology applications this ratio will soon reach 50/50. This development is being driven by a reduction in staffing levels. If fewer people are available, manual operation of the widely dispersed valves in the system becomes very problematic. In addition, process automation using central control technology continues to expand, and this of course includes all process control valves.

Apart from pure pneumatic, hydraulic or electrical drive functions, control devices with interactive capability can also perform self-monitoring and diagnostic tasks (early detection of faults and identification of fault source) as well as communications tasks using standardized methods (e.g. field bus).

Intelligent control valves thus enhance safety and contribute to reduced use of resources during production as well as increased process reliability. They exchange information in digital form with their environment and act and react independently as needed in response to changing process requirements.

In addition to the advantages mentioned above, intelligent functionality increases the service life of the valves and reduces life cycle costs. It should be kept in mind that a valve's automation costs depend on the mode of activation (manual, electric or pneumatic) as well as on the choice of the valve itself. Different combinations lead to considerably investment, operating and energy costs.

Joint research helps medium-size companies

As a result of increasing demands in the plant and pipeline construction industry, the research and development departments in the valves and fittings sector, which is principally made up of small and medium-size companies, are often stretched to the limit. A joint industry research effort, operating under the auspices of an industry group at the German Engineering Federation (VDMA), provides a well-proven alternative. A number of industrial valve and fitting manufacturers work closely with universities and research institutes to study optimization opportunities in the product development process. The project is focused on the idea that traditional product design using physical prototypes can be replaced with simulation tools that are less time and cost intensive.

What can the user expect in the future? What are the development trends in the industrial valves sector? In addition to further product development, ACHEMA 2003 will present new approaches to remote monitoring, teleservice and Internet-based control. These are trends that are very similar to those seen with pumps.

ACHEMA 2003

27th International Exhibition-Congress on Chemical Engineering, Environmental Protection and Biotechnology

Frankfurt am Main, 19 - 24 May 2003

(Source DECHEMA e.V.)