QJZ MECHANICAL DRILLING JAR

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Product Description

Working principle

Specifications

QJZ mechanical drilling jar is fully mechanically operated and is an integrated unit that provides both up and down jarring operation. As part of the drill stem, it is used to free drill string components from sticking incidents and increase drilling efficiency by providing instantaneous jarring action without delay. The mechanical drilling jar relies on a trip and friction sleeve to activate jarring action. The jar is designed to trigger the jarring action when a sufficient amount of force (jar trip load) is applied to the jar in either up or down direction.

Up Jarring

Up Jarring is achieved by pulling the drill string until it reaches the jar trip load. The jar trip load will cause the internal spring unit to deform, allowing the trip sleeve to engage the friction sleeve. When this happens, the mandrel is suddenly freed to release the jarring force. To reset the jar, remove the pull load by lowering the drill string.

● Down Jarring

There is another set of internal spring sleeve located at the top of the slips. Down Jarring is achieved by lowering(pushing) the drill string until it reaches the jar trip load. The jar trip load will cause the internal spring unit to deform, allowing the trip sleeve to engage the friction sleeve. When this happens, the mandrel is suddenly freed to release the jarring force. To reset the jar, remove the downward load by pulling the drill string

Model	QJZ95	QJZ108	QJZ121	QJZ159	QJZ165	QJZ178	QJZ203	QJZ229
Product Code	1603000	1605000	1608000	1610000	1611000	1613000	1615000	1616000
O.D. (mm)	95	108	121	159	165	178	203	229
I.D. (mm)	28	38	51	57	57	57	71.4	76.2
Total Length (mm)	6000	6000	6000	6970	6970	6468	7310	7820
Upper Stroke (mm)	200	200	200	142	142	149	145	203
Lower Stroke (mm)	200	200	200	172	172	168	178	203
Max.Up Jarring Force (kN)	200	300	430	620	620	700	800	800
Max.Down Jarring Force (kN)	100	150	300	360	360	420	450	450
Max.Tension Load (kN)	600	800	1400	2200	2200	2200	2500	3000
Max.Work Torque (kN.m)	4	8	10	15	15	15	20	25
Connection	NC26	NC31	NC38	NC46	NC50	NC50	6 5/8 Reg	7 5/8 Reg
Flexion Connection Length (mm)	3398	3370	3347	3456	3456	3476	3048	2580
Pumping Area (cm2)	33	44	50	100	100	133	176	193
Weight (kg)	360	432	573	1150	1240	1350	1780	2375