MWD Pulse Generator Principle

Pulse DL_W is consisted of sealed communication joint, fluid pressure balance device, magnetic drive, drive bar, valve stem of flow distribution, flow distribution valves, drainage sets, pressure springs, piston stem device and the signal valves.

Sealed  communication connectors are at the top of the fluid pressure balance device and connected with the magnetic drive.

Sealed joints send electrical pulse signal to the magnetic drive by connecting  communication wire, the body of the drive in magnetic drive does mechanical reciprocating motion  according to signals of pulse generator , drive drive bar, stem of flow distribution, flow distribution valve moved together.

In order to ensure the drive and  the allocation valve stem to move normally, they are sealed in the oil chamber and not in contact with drilling fluid. Fluid pressure balance device  is used to balance the pressure between oil cavity and outside drilling fluid , in order to reduce the resistance.

At the same time, the device together with the sealed communication joints, magnetic drive casing canister consist pressure and erosion-resistant shell, and ensure the normal work of machines.

When the sealed communication connectorhas dont receive  electrical pulse signals, the magnetic drive is not acting, the flow distribution valve head makes the flow distribution valve in closed state under the action of the spring in the drive bar , the fluid inside the drill string flows along the pulse generator shell at a high-speed, and all out through the signal valve annulus .

As a result of the above cross-section of different sizes and different pressure, fluid have thrust upwardin at the signal valve seat and the signal valve head , piston Department , so that the first signal overcome the spring pressure against the spring force, when  flow area of the signal valves is larger, the pressure of fluid inside the drill pipe is smaller.

When sealed communications joints received electrical pulse signal, the magnetic drive is electrified.

The electromagnetic force overcomes the pressure of spring-driven and makes drive rod, stem of the flow distribution, flow distribution valve head move together, so that the flow distribution valve head is raised, the flow distribution valves keep open for some time.

Part of the internal fluid in the apparatus flows out from the flow distribution valve spool.

Department by the signal valve ,so that the fluid flow through the signal valve annulus is reduced , resulting in a corresponding decrease for external pressure of apparatus, the thrusting  pressure upward at the signal valve seat and the signal head, the piston  is less than the spring force of spring, the original compressed spring is released , the first signal valve down , flow area between the signal valve head and the signal valve seat decreases ,resulting in system pressure of the drilling fluid within drill pipe increases .

When the 1 to 1.5 seconds later, the electrical pulse signal ends, the magnetic drive power is stopped, the flow distribution valve is closed, the system resets and the pressure drops,  this is a complete drilling fluid pressure pulse.