ZK-250 Top Drive

The architecture of the ZK-250 Top Drive is patterned after our field-proven line of power swivels. So it also has the simplicity of no gears and simply uses one hydraulic motor splined directly to the stem.

Our patented 10,000 psi washpipe seal assembly is included with quick-change washpipe.  This unique invention is auto-lubricating and provides long seal wear life during high pressure long reach drilling.

Meaningful Innovations

Also included is a patented recirculating oil circuit with numerous features. This circuit cools the hydraulic motor and load bearings when it’s hot outside, and in winter it warms the oil before startup, then cools under load. It also cools and lubricates the bearings with 10-micron filtered oil so there is no worrisome gear oil level to top off and contamination of the oil is eliminated. This patented oiling system also powers the top drive’s pipe handling functions.

Features include a dual load path to prevent tripping loads on the thrust bearing, and elevator kickout to reach out and pick up drill pipe from the mousehole or V-door.

A patented hydraulic backup wrench with a single enclosed hydraulic hose holds the drill pipe against make or break torque and may be operated remotely up in the derrick if required by downhole conditions.

A patented air-suspended thread compensator allows the top drive weight to float, preventing thread damage. No hydraulic cylinders or accumulators or hoses to leak and cause shutdown. Only one air valve, same as a truck tire, with truck tire reliability.

Patented hydraulic-actuated IBOP provides wellbore safety and serves as a mudsaver to minimize mud loss on the rig floor. Manual backup is included.

To react torque, a patented slide assembly rides on a rugged torque track hung between crown and floor. No torque loads are seen by the derrick. One man hanging in a bosun’s chair with a 2” wrench can quickly and safely make or break the patented track sections. First-time torque track rigup includes permanent attachment of our universal base plate to heavy structure, plus welding a padeye under crown for hanging the track.

Power Unit Components
All power unit components including engine, pump, tank, controls, and oil cooler are fully integrated into a well-lit, weather-tight skid-mounted container. Diesel power unit includes a Caterpillar C-18 diesel engine driving a variable-displacement piston-type hydraulic pump. Engine radiator is equipped with a blower-type fan to blow heat out of the house, and the oil cooler also discharges hot air outside. When doors at each end are closed, container is smooth outside. Hydraulic reservoir is designed to maximize floor space and service access, and electric heaters are built in to the reservoir. These heaters and the oil circulating system allow warm oil to circulate before starting the engine and pump in cold weather. A flow-thru diesel tank is included for connection to rig's central fueling system.

ZK-250 Specifications

Max Torque35,000 FT-LBS
Max Speed170 RPM
Max Static Load Rating250 TONS
Max Circulating Pressure5000 PSI
Gooseneck Connection3" API L.P.
Fluid Passage Bore Thru Stem2-3/4 I.D.
Standard Stem Connection4-1/2" I.F.
Weight10,000 LBS
XK-250 TOP DRIVE