Pneumatic penetration sensor for oil drilling

Apparatus for determining the position of a traveling block coupled to a wire line which is wrapped around a drum, comprising:

• a first motion sensor for providing a pneumatic output pulse for predetermined increment of rotation of the drum in a first direction;
• a second motion sensor for providing a pneumatic output pulse for predetermined increment of rotation of the drum in a second direction;
• a first bidirectional pneumatic counter for counting pulses from the motion sensors and providing forward and reverse pneumatic output pulses upon receipt of a predetermined number of pulses from the first and second sensors, respectively;
• one or more additional bidirectional pneumatic counters for counting pulses from the motion sensors and providing forward and reverse pneumatic output pulses upon receipt of a predetermined number of pulses from the first and second sensors, respectively;
• and
• pneumatic switching means for coupling the output of the sensors to the first counter during the wrapping or unwrapping of a first layer of wire on the drum and coupling the output of the sensors to the additional counters during the wrapping or unwrapping of second and additional layers of wire on the drum, wherein said predetermined number of input pulses per output pulse for each pneumatic counter is chosen so that an output pulse from each counter corresponds to a predetermined increment of motion of the traveling block, whereby the output pulses from the counters can be used to accurately determine the position of the traveling block.

Apparatus for accurately determining the amount of cable paid out from a drum, comprising:

• a sensor coupled to said drum for providing a predetermined number of pneumatic output pulses for each revolution of the drum;
• a first switching valve connected to the output of the sensor;
• a first pneumatic counter connected to the switching valve, wherein when the switching valve is in a first position the sensor output will be coupled to the counter, wherein the counter provides a pneumatic output pulse upon receipt of the first predetermined number of input pulses from the sensor;
• a second pneumatic counter connected to the switching valve, wherein when the switching valve is in a second position the sensor output will be coupled to the second counter, wherein the second counter provides a pneumatic output pulse upon receipt of a second predetermined number of input pulses from the sensor and wherein an output pulse from either the first and second counters corresponds to the paying out of an incremental amount of wire line from the drum;
• and
• a third pneumatic counter connected to the sensor, wherein the third counter provides a pneumatic output pulse upon the receipt of a third predetermined number of input pulses from the sensor, wherein the output of the third counter is coupled to the switching valve to cause the valve to switch from the first position to the second position, wherein the third predetermined number corresponds to the number of sensor pulses outputted during the paying out of a first layer of wire line from the drum.