Darnau drilio craidd
1. Gyda pha fath o ddyfeisiadau torri y gellir arfogi bit craidd?
a. TC (Carbid Twngsten)
b. PDC (Poly-Crystalline Diamonds Composite)
c. Diemwntau naturiol
d. Diemwntau synthetig
2. Pa fathau o ddarnau craidd a ddefnyddir yn bennaf ar gyfer drilio ymchwiliad geodechnegol ac ar gyfer pa fathau o ffurfiannau daearegol y bwriedir y darnau drilio hyn?
ü Bits armed with TC or PDC are usually used for geotechnical core drilling in soft formations such as soil, softy shale, clay and very soft sedimentary formations.
3. Soniwch am ddwy nodwedd diemwnt sy'n gwneud y diemwnt yn addas ar gyfer torri craig galed?
ü The hardness of the diamond. A diamond is the hardest known naturally occurring mineral.
ü The very high coefficient of thermal conductivity.
4.Pam na ellir defnyddio darn TC ar gyfer drilio mewn gwenithfaen?
ü The coefficient of thermal conductivity is too low.
5. Pa fathau o ddarnau diemwnt a ddefnyddir mewn drilio craidd? Disgrifiwch y gwahaniaeth rhwng y darnau craidd diemwnt hyn
ü Surface set diamond bits and impregnated diamond bits.
- Mae did diemwnt gosod arwyneb wedi'i wisgo ag un haen o ddiamwntau naturiol
imbedded yn wyneb amlen matrics caled.
- Ar did diemwnt wedi'i drwytho mae'r matrics wedi'i drwytho'n drylwyr â diemwntau bach, llawer llai na'r diemwntau a ddefnyddir mewn did arwyneb gosod.
6. Beth yw manteision diemwnt artiffisial o'i gymharu â diemwnt naturiol?
ü The technique for manufacturing synthetic diamonds has had a fast development during the last decades. Today the synthetic diamonds are superior to the natural diamonds both in terms of life length and cutting ability.
ü Another advantage with the synthetic diamonds is that these can be given special qualities required for core drilling. The synthetic diamonds can thus be "tailor made" to suit drill bits intended for different types of rock. Brittleness, grain size and geometry are three important characteristics that can be "tailor made".
7. Beth yw ystyr graffiteiddio graddol o ddiamwnt?
ü The diamonds looses their hardness and thus their ability to cut the rock.
8. Ym mha unedau ydyn ni'n mesur pwysau a maint diemwnt?
ü The weight is measured in Carats. One carat is 0,2 grams
ü The size of a diamond is measured in stones per carat (SPC).
9. Ar gyfer pa ffurfiannau daearegol y mae'r darnau diemwnt gosod arwyneb wedi'u bwriadu'n bennaf?
ü Soft to medium hard formations
10. Pryd mae did diemwnt gosod arwyneb yn cael ei fwyta?
ü When all the protruding diamonds are blunt and worn.
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