Hydrostatic pressure equalizer apparatus and system

A hydrostatic pressure equalizer device for attachment to the lower submerged end of a line connected to a source of pressurized gas, comprising:

• a hollow housing defining an internal cavity having a closed upper end and a lower end;
• an end plate extending over at least part of the lower end of the cavity;
• the lower end of the housing and the end plate defining at least one gap at the lower end of the cavity for liquid flow in to the cavity;
• the end plate having an opening for guiding the end of a gas supply line into the cavity so that an outlet end of the line is normally positioned above a normal liquid level in the cavity, whereby a pressure monitoring device connected to a gas supply end of the gas supply line above a body of liquid will detect a pressure which is a function of the hydrostatic pressure in the cavity, which in turn is equivalent to the hydrostatic pressure of the liquid in the cavity at a submerged level;
• the end plate being formed separately from the housing;
• a fastener assembly releasably securing the end plate to the open lower end of the cavity to partially close the cavity, the gap being formed between the plate and lower end of the cavity to allow water to flow into the cavity;
• and
• the fastener assembly comprising a threaded shaft extending axially through the housing and having a first portion extending upwardly from the closed end of the housing and a second portion extending through the end plate and outwardly from the lower end of the housing, a first locking nut extending over the first portion of the shaft and a second locking nut extending over the second portion of the shaft to secure the plate to the lower end of the housing.

A hydrostatic pressure equalizer device for attachment to the lower submerged end of a line connected to a source of pressurized gas, comprising:

• a hollow housing defining an internal cavity having a closed upper end and a lower end;
• an end plate extending over at least part of the lower end of the cavity;
• the lower end of the housing and the end plate defining at least one gap at the lower end of the cavity for liquid flow into the cavity;
• the end plate having an opening for guiding the end of a gas supply line into the cavity so that an outlet end of the line is normally positioned above a normal liquid level in the cavity, whereby a pressure monitoring device connected to a gas supply end of the gas supply line above a body of liquid will detect a pressure which is a function of the hydrostatic pressure in the cavity, which in turn is equivalent to the hydrostatic pressure of the liquid in the cavity at a submerged level;
• and
• the hollow housing having a cavity flush inlet for periodic connection to a supply of high pressure fluid, whereby accumulated sediment can be flushed from the cavity.

A hydrostatic pressure equalizer system for measuring hydrostatic pressure at a submerged depth in a liquid, the system comprising:

• a tubular line having a first, outlet end and a second end;
• a hollow member for submerging in a liquid medium to be monitored, the member having an internal cavity connected to the outlet end of the line;
• the cavity having a closed upper end and a lower end;
• an end plate partially closing the lower end of the cavity to leave a gap for flow of liquid into the cavity, the end plate having an opening;
• the outlet end of the line extending through the opening in the end plate and into the cavity, and terminating at a predetermined raised position which will be above a normal liquid level when the cavity is submerged;
• a gas supply connected to the second end of the line;
• a pressure responsive instrument connected to the second end of the line for producing an output proportional to the pressure in the line;
• a data processing unit connected to the output of the pressure responsive instrument for correcting the pressure output for various systematic errors and providing a corrected output signal at periodic intervals;
• and
• a guide tube projecting upwardly from the plate opening into the cavity, the gas supply line extending through the opening and upwardly through the tube up to the predetermined height above the normal water level in the cavity.

A hydrostatic pressure equalizer system for measuring hydrostatic pressure at a submerged depth in a liquid, the system comprising:

• a tubular line having a first, outlet end and a second end;
• a hollow member for submerging in a liquid medium to be monitored, the member having an internal cavity connected to the outlet end of the line;
• the cavity having a closed upper end and a lower end;
• an end plate partially closing the lower end of the cavity to leave a gap for flow of liquid into the cavity, the end plate having an opening;
• the outlet end of the line extending through the opening in the end plate and into the cavity, and terminating at a predetermined raised position which will be above a normal liquid level when the cavity is submerged;
• a gas supply connected to the second end of the line;
• a pressure responsive instrument connected to the second end of the line for producing an output proportional to the pressure in the line;
• a data processing unit connected to the output of the pressure responsive instrument for correcting the pressure output for various systematic errors and providing a corrected output signal at periodic intervals;
• and
• the hollow member having a cavity flush inlet for periodic connection to a supply of high pressure fluid, whereby accumulated sediment can be flushed from the cavity.

A method of measuring the hydrostatic pressure of a liquid at a submerged level in a liquid, comprising the steps of:

• securing the upper end of a capillary line to a gas supply and to a pressure responsive instrument;
• positioning a housing having an internal cavity at the bed of a body of liquid, the housing having a closed upper end and a lower end, an end plate extending across the lower end to leave a gap at the lower end of the cavity for entry of liquid into the cavity up to a predetermined level dependent on the hydrostatic pressure of the surrounding liquid, with an air pocket defined above the liquid level in the cavity;
• the end plate having an opening and a guide tube projecting upwardly from the opening into the cavity to a predetermined height above the liquid level in the cavity;
• extending the second end of the line through the opening in the lower end plate of the housing and upwardly through the guide tube to terminate in the air pocket above the liquid level in the cavity, whereby the output of the pressure responsive instrument is a function of the gas pressure in the cavity, which in turn is equal the hydrostatic pressure of liquid in the cavity and the region surrounding the cavity.