GB2193317A - Monitoring sludge formation in liquid-containing vessels - Google Patents

Abstract

The invention relates to the measurement or monitoring of deformations in the floor of a large liquid- containing vessel such as an oil storage tank and in particular such deformations manifested by accumulations of sludge in the bottom of the tank. The invention utilises echo sounding techniques as described in greater detail in UK patent No. 2107058 and in particular ranging between each of a multiplicity of spaced points disposed within the vessel and its floor 2, with the surface of the liquid 7 within the vessel utilised to provide a datum level. Sonic transducers 4 scan the floor 2 around their respective mounting posts 3, each transducer being mounted on a compliant walled tube (5) and circulated by peristaltic action. The oil tank has a floating roof 6. <IMAGE>

Description

SPECIFICATION Improvements in or relating to the measurement or monitoring of baseplate deformation in liquid containing vessels such as oil storage tanks This invention, like that in our UK patent No.

2107058, relates to measurement or monitoring functions and in particular to measurement or monitoring functions associated with large liquid containing vessels such as oil storage tanks. In particular, like our earlier invention, the present invention is particularly concerned with the measurement or monitoring of baseplate deformation in such vessels.

Apart from floor deformations caused by actual distortion of the tank baseplate due to settlement of the foundation sub-soil, another form of deformation is that manifested by the accumulation of sludge in the bottom of the tank. The detection and location of sludge formations is of very considerable importance since beneath accumulations of sludge corrosion can occur which tends to shorten the service life of the tank. Furthermore of course, as with deformation caused by distortion of the baseplate, deformations caused by sludge can seriously affect the apparent quantity of liquid within the tank.

According to the present invention in its broadest aspect a method or arrangement claimed in any of the claims of our UK patent No. 2107058 is utilised in order to detect and/or locate sludge formations.

Where the liquid containing vessel is an oil storage tank said sonic echosounding is provided to operate within the range of 3-700kHz.

If desired, of course, the system may be provided to operate selectively at sonic frequencies suitable for optimally detecting liquid/sludge interfaces or the baseplate whereby selectively to monitor sludge formations or baseplate distortions.

For further information regarding techniques which may be used to carry the present invention into effect, reference may be made to our earlier UK patent No. 2107058, as aforementioned. Reference may also be made to Figs. 1 and 2 of the accompanying drawing, however, which illustrate a method of carrying the present invention into effect where the liquid vessel is an oil storage tank having a so-called floating roof.

Figure 1 illustrates schematically a view looking down into the tank with the floating roof removed.

Figure 2 is a view taken in the direction of the arrows shown in Fig. 1, of a section along the line X-X. In Fig. 2 the floating roof is presumed to be in position.

Referring to Figs. 1 and 2 the oil storage tank consists of a cylindrical steel side wall 1 having a steel floor 2. Both the side wall 1 and the floor 2 are comprised of a number of component plates.

Within the tank and upstanding from the floor 2 are a plurality of posts 3 which are provided to support the floating roof 6 when the level of oil 7 drops below the tops of the posts 3.

Around each post 3 a sonic transducer 4 is arranged to travel, scanning as it does a given area of the floor 2 around the respective post 3. The areas of floor 2 scanned by the different sonic transducers 4 are arranged to overlap so that the whole of the floor 2 is addressed. The sonic transducer arrangements 4 arranged to operate in the manner described in our UK Patent No. 2107058 on the "differential measurement" principle described wherein the liquid surface is utilised as a datum level.

In the embodiment described with reference to Figs. 1 and 2 each transducer 4 is mounted on a compliant walled tube 5 and circulated by peristaltic action. The means for controlling circulation of the sonic transducers 4 and the means for connecting each sonic transducer 4 to single generating and processing means are not shown in order to avoid undue complication.

Each of the sonic transducers 4 are arranged to operate on a frequency between 3 and 700kHz in order optimally to detect oil/ sludge interfaces.

1. A method or arrangment claimed in any of the claims of UK patent No. 2107058, utilised to detect and/or locate sludge formations.

2. A method or arrangement as claimed in claim 1 and wherein the liquid containing vessel is an oil storage tank and said sonic echosounding is provided to operate within the range of 3-700kHz.

3. A method or arrangement as claimed in claim 1 or 2 and wherein the system is provided to operate selectively at sonic frequencies suitable for optimally detecting liquid/sludge interfaces or the baseplate whereby selectively to monitor sludge formations or baseplate distortions.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to the measurement or monitoring of baseplate deformation in liquid containing vessels such as oil storage tanks This invention, like that in our UK patent No. 2107058, relates to measurement or monitoring functions and in particular to measurement or monitoring functions associated with large liquid containing vessels such as oil storage tanks. In particular, like our earlier invention, the present invention is particularly concerned with the measurement or monitoring of baseplate deformation in such vessels. Apart from floor deformations caused by actual distortion of the tank baseplate due to settlement of the foundation sub-soil, another form of deformation is that manifested by the accumulation of sludge in the bottom of the tank. The detection and location of sludge formations is of very considerable importance since beneath accumulations of sludge corrosion can occur which tends to shorten the service life of the tank. Furthermore of course, as with deformation caused by distortion of the baseplate, deformations caused by sludge can seriously affect the apparent quantity of liquid within the tank. According to the present invention in its broadest aspect a method or arrangement claimed in any of the claims of our UK patent No. 2107058 is utilised in order to detect and/or locate sludge formations. Where the liquid containing vessel is an oil storage tank said sonic echosounding is provided to operate within the range of 3-700kHz. If desired, of course, the system may be provided to operate selectively at sonic frequencies suitable for optimally detecting liquid/sludge interfaces or the baseplate whereby selectively to monitor sludge formations or baseplate distortions. For further information regarding techniques which may be used to carry the present invention into effect, reference may be made to our earlier UK patent No. 2107058, as aforementioned. Reference may also be made to Figs. 1 and 2 of the accompanying drawing, however, which illustrate a method of carrying the present invention into effect where the liquid vessel is an oil storage tank having a so-called floating roof. Figure 1 illustrates schematically a view looking down into the tank with the floating roof removed. Figure 2 is a view taken in the direction of the arrows shown in Fig. 1, of a section along the line X-X. In Fig. 2 the floating roof is presumed to be in position. Referring to Figs. 1 and 2 the oil storage tank consists of a cylindrical steel side wall 1 having a steel floor 2. Both the side wall 1 and the floor 2 are comprised of a number of component plates. Within the tank and upstanding from the floor 2 are a plurality of posts 3 which are provided to support the floating roof 6 when the level of oil 7 drops below the tops of the posts 3. Around each post 3 a sonic transducer 4 is arranged to travel, scanning as it does a given area of the floor 2 around the respective post 3. The areas of floor 2 scanned by the different sonic transducers 4 are arranged to overlap so that the whole of the floor 2 is addressed. The sonic transducer arrangements 4 arranged to operate in the manner described in our UK Patent No. 2107058 on the "differential measurement" principle described wherein the liquid surface is utilised as a datum level. In the embodiment described with reference to Figs. 1 and 2 each transducer 4 is mounted on a compliant walled tube 5 and circulated by peristaltic action. The means for controlling circulation of the sonic transducers 4 and the means for connecting each sonic transducer 4 to single generating and processing means are not shown in order to avoid undue complication. Each of the sonic transducers 4 are arranged to operate on a frequency between 3 and 700kHz in order optimally to detect oil/ sludge interfaces. CLAIMS

1. A method or arrangment claimed in any of the claims of UK patent No. 2107058, utilised to detect and/or locate sludge formations.

2. A method or arrangement as claimed in claim 1 and wherein the liquid containing vessel is an oil storage tank and said sonic echosounding is provided to operate within the range of 3-700kHz.

3. A method or arrangement as claimed in claim 1 or 2 and wherein the system is provided to operate selectively at sonic frequencies suitable for optimally detecting liquid/sludge interfaces or the baseplate whereby selectively to monitor sludge formations or baseplate distortions.