{"id":1588588,"date":"2025-06-13T16:53:12","date_gmt":"2025-06-13T13:53:12","guid":{"rendered":"https:\/\/steiner.com.ua\/?post_type=product&p=1588588"},"modified":"2026-08-31T13:11:05","modified_gmt":"2026-08-31T10:11:05","slug":"kral-trygvyntovyj-nasos-z-series","status":"publish","type":"product","link":"https:\/\/steiner.com.ua\/en\/catalog\/kral-trygvyntovyj-nasos-z-series\/","title":{"rendered":"KRAL \u2013 Twin-screw pump (Z Series)"},"content":{"rendered":"

The KRAL Z Series twin-screw pump handles media that triple-screw pumps cannot handle: bitumen, heavy petroleum products, contaminated and non-lubricating fluids. Manufacturer: KRAL, Austria. This is the series with the highest flow rate in the manufacturer\u2019s range: from 330 to 17,660 litres per minute, i.e. 20\u20131,060 m\u00b3\/h, with viscosities up to 100,000 mm\u00b2\/s and media temperatures ranging from \u221240 to +300 \u00b0C.<\/p>\n

How does a twin-screw pump differ from a triple-screw pump?<\/h2>\n

In a triple-screw pump, the drive screw rotates the two driven screws via the fluid itself; therefore, the fluid must have lubricating properties. In the Z Series, the screws are synchronised by a gear train and do not come into contact with one another, whilst the bearings are located outside the flow path and are not washed by the product. Consequently, the series can handle fluids without lubricating properties, those containing mechanical impurities, or chemically aggressive fluids \u2014 this is precisely how KRAL positions it.<\/p>\n

The casing features a double-suction design: the flow is split and enters the screw pair from both sides, which balances the axial forces without internal bypass. The Delta-design housing geometry reduces hydraulic losses and improves suction capacity.<\/p>\n

For a general explanation of how a screw pair works, see the article Features of screw pumps<\/a>.<\/p>\n

Technical Specifications of the KRAL Z Series<\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nValue<\/th>\n<\/tr>\n<\/thead>\n
Type<\/td>\ntwin-screw pump with synchronised screws and double suction<\/td>\n<\/tr>\n
Capacity<\/td>\n330\u201317,660 litres per minute (20\u20131,060 m\u00b3 per hour)<\/td>\n<\/tr>\n
Standard sizes<\/td>\nZ03000 \u2014 up to 270 m\u00b3\/h \u00b7 Z05000 \u2014 up to 490 m\u00b3\/h \u00b7 Z11000 \u2014 up to 1,060 m\u00b3\/h<\/td>\n<\/tr>\n
Max. differential pressure<\/td>\n25 bar<\/td>\n<\/tr>\n
Fluid temperature<\/td>\n\u221240\u2026+300 \u00b0C<\/td>\n<\/tr>\n
Operating viscosity<\/td>\n0.7\u2013100,000 mm\u00b2\/s<\/td>\n<\/tr>\n
Housing material<\/td>\nspheroidal graphite cast iron or welded carbon steel<\/td>\n<\/tr>\n
Screws<\/td>\nsolid or composite<\/td>\n<\/tr>\n
Gaskets<\/td>\nsingle or double end-face, optional leak detection<\/td>\n<\/tr>\n
Bearings<\/td>\nlocated externally, outside the medium being pumped<\/td>\n<\/tr>\n
Installation<\/td>\nhorizontal and vertical<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Design and construction<\/h2>\n

Casing heating \u2014 integrated heating jacket; available in electric, steam or heat-transfer fluid versions. A circulation valve is fitted to protect against overpressure. Seals are fitted with supply systems in accordance with API specifications, with leak detection where required. The manufacturer states that the series is capable of dry running.<\/p>\n

Manufactured in accordance with API 676. Classification society certificates: ABS, BV, DNV-GL, LRS, RINA.<\/p>\n

The external bearings have another practical advantage: replacing the seal and servicing the unit do not require contact with the product, which is important when dealing with bitumen and heavy residues.<\/p>\n

Where is the Z Series twin-screw pump used?<\/h2>\n