Taprogge

Schematic representation of the cleaning process and of the filtration technology

The Taprogge GmbH is a medium-sized company based in Wetter, district Wengern, on the river Ruhr in Germany. The limited company was founded by the merchant Ludwig Taprogge (* 18 September 1920) at Duesseldorf-Angermund on 1 March 1953 and has since then been producing tube cleaning systems for condensers and heat exchangers and, at a later stage, also debris filters for water-cooled shell-and-tube heat exchangers and condensers. The family business with a staff of around 350 is regarded as market leader in this technological field and has subsidiaries and agencies in many countries of the world.

Company Development

The first freelancer of the company was the company founder's brother, Josef Taprogge (* 15 November 1914, † 27 November 1961), an engineer for power station technology in the then steam power plant at Essen-Kupferdreh. As the works manager he was responsible for the cleaning of the turbine condenser tubes, a time-consuming and very dirty activity. Cleaning had to be performed while the turbine was out of operation, with the power station not being able to supply any electrical energy to the grid during the turbine outage. On the other hand, the careful elimination of fouling from inside of the tubing is extremely important for a high vacuum in the condenser and thereby for the optimal efficiency of the energy generation through water vapour. After such a cleaning, however, the tubes fouled again very quickly. To avoid economic losses caused by this situation, Josef Taprogge invented a continuously working cleaning system which, during the operation of the steam turbine, kept the condenser free from fouling, and installed a prototype into the cooling water pipe leading to the condenser. During the time of the German Wirtschaftswunder, the process which was marketed and further developed by Taprogge was widespread and very well received in the power stations due to its efficiency. The efficiency of the power stations that are equipped with the systems increases by around 2 – 4 %, so that the investment pays back within few months. The cleaning process became so famous among experts that to date the name "TAPROGGE System" has been used in the technical literature. The company grew rapidly. Already in 1957 a subsidiary could be founded in USA. Further subsidiaries followed in Great Britain (1963) and Japan (1967). The latest foundation was the establishment of a Chinese production site in Shanghai on 15 December 1997.

Tube Cleaning Systems

A typical assortment of cleaning balls

The patented process invented by Josef Taprogge is a matter of sponge rubber balls which are injected into the cooling water flow (1) before it enters into the condenser. The diameter of the cleaning balls is slightly bigger than the nominal diameter of the condenser tubing. Due to their elasticity they generate a contact pressure on their way through the condenser tubes by which all fouling is reliably removed from the inner tube walls. At the condenser outlet a strainer (2) is installed in the connecting pipe which separates the balls from the water flow and feeds them into a DN 80 pipe. From there the balls are pumped back to their starting point by a 4 kW impeller pump via a DN 80 pipe. To inject the balls into the cycle, a pressure vessel with detachable cover is installed downstream of the pump. This so-called collector (3b) is equipped with a screen and a flap. At open flap, the balls can pass and with closed flap they remain in the collector and can be replenished or exchanged. The process works continuously, the tubes remain free from tenacious fouling like mud, algae, bacteria and scaling. The operation of the system is monitored via sight glasses and electronic measuring instruments. The screen surfaces are arranged on shafts with pivoted bearings and can be turned on demand to have fouling removed by the water flow. In this process the balls are caught in the collector. This time-consuming procedure is automatized (3c), gear motors (M) operate the relevant actuators. The nominal diameters of the screens have been adjusted to respond to the developments in power station technology and are produced in sizes from nominal diameter 150 mm to 3600 mm. The cleaning ball diameters range from 14 to 30 mm, and one collector filling normally consists of several hundreds up to far more than 1000 balls. The lifetime of the cleaning balls which are produced of biodegradable natural rubber may last max. 4 weeks.

A specialized technology is the production of tube cleaning systems for seawater desalination plants. As the heated seawater called brine has a particularly corrosive effect, highly resistant materials have to be used for such systems. Due to the large tube diameters in the evaporators, the cleaning balls have diameters of up to 45 mm.

Debris Filtration Systems

Backflush filter with large nominal diameter

In the seventies, the product range was extended by backwash filters to protect the heat exchangers and condensers from macro fouling, like stones, pieces of wood, fibres, plastic foil and mussels. Foreign matter will first settle on the filter surface. As soon as the accumulated fouling has built up a certain differential pressure between filter inlet and outlet, the filter is backwashed. For this purpose an electrically driven rotor covers the filter surface which is connected with a pipe leading outside. Installed in this pipe is a valve that is opened during the backwash process. The accumulated fouling is drawn off and discharged via the pipe which, downstream of the condenser, leads to the main cooling water pipe or a debris container. This technology was spread in power stations and industrial plants the world over. Depending on the flow rates to be filtered, the filters are produced in nominal diameters from 150 mm to DN 3200 mm. The filter surface consists of stainless steel with punched holes. For difficult types of debris, filter surfaces of plastic or grids can be used. A further type produced by the company are fine filters with filtration degrees from 50 to 1000 µm.

Water Intake Systems

Airflushed intake filter with TAPIS® -Design

Since the late 90s, Taprogge offers another filter system which retains fouling already at the intake into the cooling water system – in this way the entire system and the long cooling water pipes can be protected. The system called TAPIS® (Taprogge Air Powered Intake System) is installed in the water at the cooling water pipe inlet in the form of a polyhedral housing with plain filter surfaces. It is cleaned by pressurized air blast. In contrast to submarine rakes for seaborne matter, the stainless steel filter has no moving parts and masters biggest water flows. The filter surfaces are made of coated plastic provided with drilled holes.

Market positioning

Taprogge GmbH is regarded as market leader in its market segment. Taprogge Systems not only cause improved power station efficiency but also contricute to the reduction of carbon dioxide emissions in fossile fired steam power plants. Nearly 90% of all steam power plants of the world are equipped with Taprogge tube cleaning systems and debris filters, and there is a similar market penetration in the industrial sector. Since 1984 the company has been based in Wengern, with subsidiaries and production sites, among others, in Japan, China and USA. Agencies and subsidiaries established in more than 60 countries over the world. One special feature of the products of the company is their ability to be individually adjusted to customers' needs. The products are projected, designed and produced on Taprogge's own premises, the workshop floor has more than 10,000 sqm.

Literature

• Verminderung der Belags- und Korrosionsbildung in Kraftwerken: Handbuch; Brennstoffauswahl, Monitoring, Konstruktive Maßnahmen, Reinigungssysteme / Essen, Ruhr: Publico Publ., 2004 page 256ff Springer VDI publishers ISBN 3-934736-13-0
• Essay on step-by-step filtration of cooling water (http://dbindustrie.work.svhfi.de/AI/resources/bdc89e9eaeb.pdf)

Website

• http://www.taprogge.de (German and English)