Prover Sphere Inspection

Question 1

What is the maximum allowable size (without an MOC) of the prover sphere compared to the inner diameter?

Answer 1

105%

Question 2

What is the maximum durometer value (hardness) difference from the most recent prover calibration?

Answer 2

+/- 10

Question 3

Where should the prover sphere size and durometer reading be documented?

Answer 3

In the records of prover calibration.

Question 4

What are the sphere inspection frequencies?

Answer 4

With a batch scheduled system inspect annually. With a non-batch scheduled system it’s (greater than 1 million, monthly bbls annually, between 100,000 and 1 million 1/2 prover calibration frequency, less than 100,000 equivalent to prover calibration frequency). There is a photo for this answer in the book.

Question 5

What are the prover sphere inspection sizing tools?

Answer 5

A caliper with a measuring tape, or a 1/4” circumference tape either stainless steel or plastic coated.

Question 6

What would you fill a sphere with?

Answer 6

50/50 blend of glycol and water. If temperatures are expected to be above 150 deg. F, 100% glycol may be required.

Question 7

How should spheres be stored?

Answer 7

Indoors out of direct sun light, cradled in sand or foam or half section of pipe or suspended in a net.

Question 8

Where should you take measurements from while checking hardness?

Answer 8

Take measurements from at least two locations for one-piece spheres and from at least two points per half for two-piece spheres.

Question 9

What temperature should take durometer readings from the sphere?

Answer 9

As close as possible to the temperature at which the manufacturer made their readings.

Question 10

Where should a sphere be measured for ovality and size?

Answer 10

Around two separate axes perpendicular to each other.

Question 11

What is the max acceptable difference between current and last sphere size measurement?

Answer 11

Less than 0.5% difference.

Question 12

Where can the maximum circumference variation be found?

Answer 12

It varies and is located in TMG.01 on page 9 of the measurement proficiency demonstration book.

Question 13

What is required to be done after re-sizing the sphere?

Answer 13

Verify sphere size and ovality.

Question 14

What should you make sure to do when filling the sphere?

Answer 14

Empty all of the air out of the ball. Agitation may be needed to help the process.

Question 15

What is the maximum allowable size difference between as found and previous as left? What is required to be done if it is over this tolerance?

Answer 15

1% is the maximum allowable size difference. Contact a measurement analyst if the size difference is more than 1%.

Question 16

Give a general description of the types of spheres.

Answer 16

Yellow Poly 0-150 deg F all but chemicals, Green Poly 0-180 all, Red or Blue Poly for chemicals 0-180, Black Neoprene for crude -20-270 deg. F.

Question 17

What imperfections are you looking for on the sphere?

Answer 17

deep cuts, extreme pitting, holes, flat spots, soft spots, and any condition that would cause leaks or loss of seal.

Question 18

What are the steps to fill a dual valve sphere?

Answer 18

Remove one of the valves and connect pump to other valve. Fill until all air displaced. Replace valve and fill to correct size.

Question 19

What are the steps to fill a single valve sphere?

Answer 19

Remove valve and fill with fluid until all air is displaced. Replace valve and fill to correct size.