KRACHT BT / BTH Low-Speed Gear Pump

Overview

The KRACHT BT series, together with the heated BTH version, comprises low-speed external gear pumps for transferring medium to high viscosity liquids that have a certain minimum lubricity, contain no solid particles and are chemically compatible with the materials of construction. KRACHT GmbH, the German pump specialist within the Atlas Copco Group, builds the KRACHT BT in eight sizes from BT 0 to BT 7 with nominal displacements of 6.9 to 494 cm³/rev, while the BTH covers 97 to 1 056 cm³/rev. The pumps run at 100 to 750 rpm, handle viscosities from 76 to 30 000 mm²/s and media temperatures from -10 to 220 °C, and deliver up to 8 bar on sizes BT 1 to BT 7.

Seven Star LLC supplies the KRACHT BT and BTH gear pumps to tank farms, lubricant blenders, chemical plants and asphalt and bitumen users across the Sultanate of Oman and the GCC, with engineering support in Muscat. We help buyers size the pump against viscosity, flow and drive power using the KRACHT performance tables, and can quote bare pumps or complete units with motor, coupling and base plate for delivery to Muscat, Sohar, Duqm or Salalah.

Operating Principle of the KRACHT BT

The KRACHT BT is a positive displacement pump: a driving gear and a driven gear mesh inside the housing, and liquid trapped in the tooth spaces is carried around the housing wall from the suction port to the discharge port. Because delivery is proportional to speed and largely independent of pressure, the pump gives a steady, controllable flow, and its low operating speed is deliberately chosen for viscous liquids, which need time to fill the tooth spaces completely. As general engineering background, running a gear pump slowly on thick fluids prevents cavitation at the inlet, reduces shear on sensitive products and keeps drive power moderate.

For liquids that only flow at elevated temperature, such as bitumen or wax, KRACHT offers the BTH series. Its housing is double-walled to form a heating jacket through which heat transfer oil or steam circulates at up to 10 bar, keeping the pump chamber warm so that the product does not solidify in the pump during start-up or standstill.

Engineering Design of the KRACHT BT

The housing, bearing cover and stuffing box cover of the KRACHT BT are made of grey cast iron as standard. Shafts and gears are manufactured from case-hardening steel, hardened and ground, and run in bronze plain bearings, with sintered iron as an option. The shaft is sealed by a packed gland of PTFE-filled aramid yarn, and static joints use liquid sealant or gaskets, all asbestos-free. The pumps are foot-mounted, installed horizontally, connected with Whitworth pipe threads (BTH also with flanges) and driven preferably through a flexible coupling. External axial loads are not permitted, while limited radial loads can be absorbed.

Several special constructions extend the range. BT 2 can be built in corrosion- and acid-resistant stainless steel with carbon bearing bushes, limited to 5 bar. BT 1 to BT 4 can be supplied with bronze housings and combinations of stainless steel or bronze gears and stainless shafts. For abrasive and corrosive liquids such as resins, certain paints, varnishes and glues, the code 04 construction protects all wetted parts with a chemically deposited nickel and silicon carbide dispersion layer, available for BT 1 to BT 7. ATEX versions with a mechanical seal and liquid reservoir are offered for sizes BT 3 to BT 7.

Key Features of the KRACHT BT

The KRACHT BT and BTH series offer the following practical benefits:

• Eight BT sizes from 6.9 to 494 cm³/rev and five BTH sizes from 97 to 1 056 cm³/rev.
• Low speed range of 100 to 750 rpm suited to medium and high viscosity liquids.
• Viscosities from 76 to 30 000 mm²/s, with other viscosities on request.
• Media temperatures from -10 to 220 °C, with a heating jacket on BTH for bitumen, wax and similar products.
• Discharge pressure up to 8 bar on BT 1 to BT 7, with higher pressures on request.
• Case-hardened, ground steel gears and shafts running in bronze plain bearings.
• Clockwise and anticlockwise rotation on BT, with stainless, bronze and Ni/SiC-coated special versions.
• Optional complete unit with electric motor, coupling and guard on a common base plate.

Industrial Applications

The KRACHT BT is typically used to transfer and circulate lubricating oils, fuel oils, molasses, resins, paints, varnishes, glues and similar liquids, while the BTH handles bitumen, wax and other products that need heating to flow. In Oman and the GCC this covers lube oil blending and drum filling, fuel oil transfer at power and desalination plants, asphalt and bitumen handling for road construction, resin and paint production in the Sohar and Rusayl industrial estates, and food-grade molasses and syrup transfer where materials are suitable.

Seven Star LLC supplies the KRACHT BT with motors and couplings and can recommend higher-pressure alternatives where needed, for example the KF Series modular gear pump or the KP Series internal gear pump. For measuring the transferred volume, the VCM gear flow meter from the same manufacturer is also available through our team in Muscat.

Technical Specifications

The table below summarises the KRACHT BT and BTH data from the manufacturer datasheet:

How to Order

For a formal quotation on the KRACHT BT or BTH, send Seven Star LLC the liquid, viscosity at pumping temperature, required flow, discharge pressure and any heating requirement. Our engineers in Muscat will select the size and speed, confirm drive power and arrange delivery of a bare pump or complete unit anywhere in Oman or the GCC. The manufacturer datasheet with performance tables, dimensions and weights can be downloaded from this page.