cracking ..... that it is in proper working condition

[JACEK1]

Hello all forum users!

WARNING! As per SOLAS-requirements, check-lifting must be carried out before loading, discharging and ballasting is commenced. If the valve disc does not move freely, the cause should be determined and corrected immediately. If a lever is used, cracking the valve open would not be adequate evidence that it is in proper working condition. It is likely clogged.

In my opinion, the underlined fragment in bold type means the following:

If a lever is used, opening the valve (by force) would not provide adequate evidence that the valve is in proper working condition.


The fragment is taken from operating/maintenance instructions for HS-ISO pressure valve.

I am particularly interested in the meaning "to crack something open. I think it means "to open something by force" and is similar in meaning to "to break something open". I may be wrong.

 

[MikeNewYork]

Yes, it would mean opening the valve by force.

 

[Gillnetter]

Hello all forum users!

WARNING! As per SOLAS-requirements, check-lifting must be carried out before loading, discharging and ballasting is commenced. If the valve disc does not move freely, the cause should be determined and corrected immediately. If a lever is used, cracking the valve open would not be adequate evidence that it is in proper working condition. It is likely clogged.

In my opinion, the underlined fragment in bold type means the following:

If a lever is used, opening the valve (by force) would not provide adequate evidence that the valve is in proper working condition.


The fragment is taken from operating/maintenance instructions for HS-ISO pressure valve.

I am particularly interested in the meaning "to crack something open. I think it means "to open something by force" and is similar in meaning to "to break something open". I may be wrong.

To "crack open" doesn't imply force. It usually means just to open something. "Let's go to the beach and crack open a couple of beers", merely means that we will open a couple of beers. The bit about using a lever confuses the issue as using a lever implies that more force is needed than another method - which is not disclosed in the text.

 

[MikeNewYork]

It requires force to "'crack open" a beer. And then there is crack open a safe, a coconut, etc. In addition, the lever also implies force.

 

[billmcd]

While certainly not familiar with the operation, in the context provided I would agree with your interpretation.

 

[5jj]

It requires force to "'crack open" a beer.

I don't think many people would associate cracking open a beer with force.

 

[emsr2d2]

I don't associate force with opening beer cans either. If you crack open the door, you open the door a crack.
I assumed that "cracking the valve open" meant only opening it a tiny bit.

 

[Route21]

I don't associate force with opening beer cans either. If you crack open the door, you open the door a crack.
I assumed that "cracking the valve open" meant only opening it a tiny bit.

Spot on!

As a retired NES chemical engineer (oil, gas and petrochemical industries), but not a teacher:

Cracking a valve open very specifically means opening it a small amount. It does not, per se, imply any significant force is used.

Almost all 1/4-turn on/off valves (e.g. ball/plug valves) have a lever, which is, traditionally in line with the pipe when open and at right angles to it when closed. Those that don't have a physical lever would likely have an actuator to perform the same duty.

Regards
R21

 

[Route21]

I don't associate force with opening beer cans either. If you crack open the door, you open the door a crack.
I assumed that "cracking the valve open" meant only opening it a tiny bit.

Rising stem valves, such as "gate valves", are, by their nature, hand-wheel rather than lever-operated. They are opened either by hand-wheel, chainwheel or a "wheel-key". They are more likely to get stuck in the closed position, if fouled, which is where the wheel-key comes in handy to provide additional leverage beyond the radius of the hand-wheel.

Regards
R21

PS SOLAS stands for Safety of life at sea. In situations where timing is critical, I would expect to see primarily ball valves used as they are quick to operate.

 

[Route21]

The OP mentions "pressure valve" and "disc".

If, by that, the OP actually means a "Pressure Relief Valve" (PRV), that might explain the reference to a "disc".

What the O&M manual could be saying is that, just because you can actually "lift" (move) the spring-loaded disc, it doesn't mean that the PRV will be able to open sufficiently to relieve any overpressure. Without details of the system from the OP, it's not possible to see where any overpressure or fouling would come from.

The thing that I find confusing from the OP was that I would not expect to see an unprotected, fouled relief valve, particularly in a SOLAS situation, where lives are at risk. I would expect the inlet of the relief valve to be protected by a carbon or metal "rupture/bursting disc", with a pressure gauge between the disc and the PRV, to identify if the disc had blown. If it has, the PRV should be removed, cleaned and "popped", to ensure it opens and closes at the correct pressures.

Regards
R21

PS The OP should be able to understand the technicalities in these posts.

See:
http://en.m.wikipedia.org/wiki/Pressure_relief_valve

 

[MikeNewYork]

Route 21, I appraciate your comments. You obviously have experience in this area. I would then assume that you understand the meaning of force, as it exists in physics. Since this is a technical manual, I would think that definition is acceptable. It is an influence that causes a change in an object's motion, direction, or physical construction. That is clearly the case here. In addition, the manual specifically refers to the use of a lever to "crack the valve open". Even if this is just opening the valve a little bit, the use of a lever implies applying more than the normal level of force. I get the image of a valve that was stuck. And the manual says that if one successfully opens, but needs a lever to do so, it does not mean that the valve works properly.

 

[5jj]

the use of a lever implies applying more than the normal level of force.

It may fo. However, it is the word 'lever' that may imply force, not 'cracking open'.

 

[MikeNewYork]

Yes, lever was always an important part of the equation.