{"id":1588571,"date":"2025-06-12T12:21:56","date_gmt":"2025-06-12T09:21:56","guid":{"rendered":"https:\/\/steiner.com.ua\/?post_type=product&p=1588571"},"modified":"2026-08-31T16:13:12","modified_gmt":"2026-08-31T13:13:12","slug":"kral-trygvyntovyj-nasos-w-series","status":"publish","type":"product","link":"https:\/\/steiner.com.ua\/en\/catalog\/kral-trygvyntovyj-nasos-w-series\/","title":{"rendered":"KRAL - Three screw pump (W Series)"},"content":{"rendered":"

The KRAL W-series coolant pump is designed for fluids that damage conventional pumps: water-miscible lubricating and cooling fluids, cutting emulsions and lubricants, and contaminated media containing abrasive particles. Manufacturer: KRAL, Austria. The challenge here lies not in viscosity, but in the combination of low viscosity with high pressure and solid particles \u2014 this is precisely what the W series screw pump pair is designed for.<\/p>\n

For which liquids is the W series designed?<\/h2>\n

The manufacturer describes the scope of application as \u2018complex fluids\u2019: low-viscosity fluids that need to be delivered under high pressure and which contain abrasive particles. A typical example is the coolant circuit on a machine tool: the fluid is diluted with water, its viscosity is close to one, and swarf dust is present in the flow.<\/p>\n

A standard three-screw pump quickly loses its clearance in such an environment. In the W series, the screws are made of nitrided steel and fitted almost tightly, whilst the housing is available with a polymer coating \u2014 this ensures a long service life even where viscosity is insufficient to maintain a hydraulic film.<\/p>\n

On the principle of operation of a screw pair \u2014 how a screw pair works<\/a>.<\/p>\n

Technical specifications of the KRAL W Series<\/h2>\n
\n\n\n\n\n\n\n\n\n
Size<\/th>\nQth flow rate (1450 min\u207b\u00b9, 0 bar)<\/th>\n<\/tr>\n<\/thead>\n
15-26<\/td>\n15\u201326 l\/min<\/td>\n<\/tr>\n
32-54<\/td>\n32\u201354 l\/min<\/td>\n<\/tr>\n
55-85<\/td>\n55\u201385 l\/min<\/td>\n<\/tr>\n
105-118<\/td>\n105\u2013118 litres per minute<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Parameters common to a number of items:<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nValue<\/th>\n<\/tr>\n<\/thead>\n
Type<\/td>\nthree-screw pump<\/td>\n<\/tr>\n
Pressure at the discharge flange<\/td>\nup to 120 bar<\/td>\n<\/tr>\n
Pressure at the suction flange<\/td>\nup to 6 bar<\/td>\n<\/tr>\n
Minimum viscosity<\/td>\n1.0 mm\u00b2\/s<\/td>\n<\/tr>\n
Maximum viscosity<\/td>\n10,000 mm\u00b2\/s<\/td>\n<\/tr>\n
Housing material<\/td>\nhigh-strength EN-GJS-400 cast iron, with a polymer coating, or other materials to order<\/td>\n<\/tr>\n
Screws<\/td>\nnitrided steel<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

The manufacturer\u2019s specifications cover a wider range of sizes \u2014 from W 15 to W 275. Sizes outside these four ranges are available to order on a case-by-case basis.<\/p>\n

The seal determines the operating temperature<\/h2>\n

In the W series, the temperature depends not on the housing but on the type of seal. This is the key factor in choosing a model.<\/p>\n

\n\n\n\n\n\n\n\n\n\n
Gaskets<\/th>\nMax. fluid temperature<\/th>\n<\/tr>\n<\/thead>\n
Cuff-type, NBR<\/td>\n90 \u00b0C<\/td>\n<\/tr>\n
Cuff-type, FKM<\/td>\n150 \u00b0C<\/td>\n<\/tr>\n
Standard end-face<\/td>\n150 \u00b0C<\/td>\n<\/tr>\n
End-face made from hard materials<\/td>\n180 \u00b0C<\/td>\n<\/tr>\n
Magnetic clutch<\/a><\/td>\n300 \u00b0C<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

For the mechanical seal, the manufacturer\u2019s instructions specify 80 \u00b0C instead of 90 \u00b0C. This difference should be taken into account when performing calculations at the limits of the range.<\/p>\n

The polymer-coated casing has its own temperature limit \u2014 up to 60 \u00b0C, according to the manufacturer\u2019s instructions.<\/p>\n

Where are W-series pumps used?<\/h2>\n