Fluid monitoring apparatus including fluid density detection system for subsea apparatus

1. A subsea equipment-protection apparatus comprising a fluid monitoring apparatus for detecting which of a first fluid, a second fluid and a third fluid is present, the second fluid having a density less than the first fluid and the third fluid having a density less than the second fluid, the fluid monitoring apparatus comprising:

a first float having a density less than that of the first fluid but greater than that of the second fluid;

a second float having a density less than that of the second fluid but greater than that of the third fluid; and

a sensor,

the first float being allowed to float when a fluid with density greater than the density of the first float is present and being allowed sink when a fluid with density less than the density of the first float is present,

the second float being allowed to float when a fluid with a density greater than the density of the second float is present and being allowed to sink when a fluid with a density less than the density of the second float is present, and

the sensor being configured to detect the first float and the second float so that the position of the floats can be determined.

2. The subsea equipment-protection apparatus as claimed in claim 1 , comprising:

a passageway through which fluid may pass from a first end to a second end, the passageway having a first opening at the first end and a second opening at the second end,

the apparatus being arranged such that the first float and the second float may float and sink relative to the passageway in order to open and close the passageway dependent on the density of fluid present.

3. The subsea equipment-protection apparatus as claimed in claim 2 , the first float being allowed to float to a first position when a fluid with density greater than the density of the first float is present and being allowed sink to a second position when a fluid with density less than the density of the first float is present, and the second float being allowed to float to a first position when a fluid with a density greater than the density of the second float is present and being allowed to sink to a second position when a fluid with a density less than the density of the second float is present,

the apparatus being configured such that the second float seals the first opening of the passageway when in the first position, and the first float and the second float are distant from the first opening of the passageway when in the second positions thus allowing fluid to pass through the passageway.

4. The subsea equipment-protection apparatus as claimed in claim 2 , the first float being allowed to float to a first position when a fluid with density greater than the density of the first float is present and being allowed sink to a second position when a fluid with density less than the density of the first float is present, and the second float being allowed to float to a first position when a fluid with a density greater than the density of the second float is present and being allowed to sink to a second position when a fluid with a density less than the density of the second float is present,

the apparatus being configured such that the first float seals the second opening of the passageway when in the second position, and the first float and the second float are distant from the second opening of the passageway when in the first positions thus allowing fluid to pass through the passageway.

5. The subsea equipment-protection apparatus as claimed in claim 2 , wherein the first and/or second float comprises a stopping member configured to prevent the first and/or second float from being fully withdrawn from the passageway.

6. The subsea equipment-protection apparatus as claimed in claim 5 , wherein the stopping member comprises openings for allowing fluid to pass therethrough.

7. The subsea equipment-protection apparatus as claimed in claim 1 , wherein the first fluid is sea water, the second fluid is oil and the third fluid is gas.

8. The subsea equipment-protection apparatus as claimed in claim 1 , wherein the first and second floats are each provided with stops configured to limit the extent of their relative displacement.

9. The subsea equipment-protection apparatus as claimed in claim 1 , further comprising a protective cap.

10. The subsea equipment-protection as claimed in claim 1 , comprising a surface, the surface comprising an opening in which the fluid monitoring apparatus is located.

11. The subsea equipment-protection as claimed in claim 10 , wherein the surface is convex, the fluid monitoring apparatus and the opening being located in an upper portion of the surface.

12. A fluid monitoring apparatus for detecting which of a first fluid, a second fluid and a third fluid is present, the second fluid having a density less than the first fluid and the third fluid having a density less than the second fluid, the apparatus comprising:

a first float having a density less than that of the first fluid but greater than that of the second fluid;

a second float having a density less than that of the second fluid but greater than that of the third fluid;

a sensor,

the first float being allowed to float when a fluid with density greater than the density of the first float is present and being allowed sink when a fluid with density less than the density of the first float is present,

the second float being allowed to float when a fluid with a density greater than the density of the second float is present and being allowed to sink when a fluid with a density less than the density of the second float is present, and

the sensor being configured to detect the first float and the second float so that the position of the floats can be determined;

a passageway through which fluid may pass from a first end to a second end, the passageway having a first opening at the first end and a second opening at the second end,

the apparatus being arranged such that the first float and the second float may float and sink relative to the passageway in order to open and close the passageway dependent on the density of fluid present,

wherein the first float and the second float each comprise an end portion and a rod portion,

the rod portions of the first and second floats both passing at least partially through the passageway,

the end portions of the first and second floats being orientated perpendicularly to the rod portions, and

the end portion of the first and/or second float being shaped to seal the passageway.

13. The fluid monitoring apparatus as claimed in claim 12 , wherein the rod portions of the first and second float may be configured to slide relative to one another telescopically.

14. A fluid monitoring apparatus for detecting which of a first fluid, a second fluid and a third fluid is present, the second fluid having a density less than the first fluid and the third fluid having a density less than the second fluid, the fluid monitoring apparatus comprising:

a first float having a density less than that of the first fluid but greater than that of the second fluid;

a second float having a density less than that of the second fluid but greater than that of the third fluid;

a passageway through which fluid may pass from a first end to a second end, the passageway having a first opening at the first end and a second opening at the second end; and

a sensor,

the first float being allowed to float when a fluid with density greater than the density of the first float is present and being allowed sink when a fluid with density less than the density of the first float is present,

the second float being allowed to float when a fluid with a density greater than the density of the second float is present and being allowed to sink when a fluid with a density less than the density of the second float is present,

the sensor being configured to detect the first float and the second float so that the position of the floats can be determined,

wherein the first and/or second float comprises a stopping member configured to prevent the first and/or second float from being fully withdrawn from the passageway,

wherein the first float and the second float may float and sink relative to the passageway in order to open and close the passageway dependent on the density of fluid present, and

wherein the stopping member of the first and/or second float is housed within a protective cap.

15. A fluid monitoring apparatus for detecting which of a first fluid, a second fluid and a third fluid is present, the second fluid having a density less than the first fluid and the third fluid having a density less than the second fluid, the apparatus comprising:

a first float having a density less than that of the first fluid but greater than that of the second fluid;

a second float having a density less than that of the second fluid but greater than that of the third fluid; and

a sensor,

the first float being allowed to float when a fluid with density greater than the density of the first float is present and being allowed sink when a fluid with density less than the density of the first float is present,

the second float being allowed to float when a fluid with a density greater than the density of the second float is present and being allowed to sink when a fluid with a density less than the density of the second float is present, and

the sensor being configured to detect the first float and the second float so that the position of the floats can be determined,

wherein the sensor comprises a magnet attached to the first and/or second float and a coil surrounding the magnet.