WO1991016502A1

WO1991016502A1 - Outfall monitoring

Info

Publication number: WO1991016502A1
Application number: PCT/GB1991/000592
Authority: WO
Inventors: Keith Thatcher
Original assignee: Dunlop Limited
Priority date: 1990-04-17
Filing date: 1991-04-16
Publication date: 1991-10-31
Also published as: GB9108070D0; GB2246441A; AU7690091A; GB2246441B

Abstract

Method and apparatus for monitoring the outfall of discharge pipes (10) in which a measuring unit is provided in the vicinity of the outfall in a submerged location and arranged to act as a monitoring unit which transmits information to an onshore site (19). Preferably the measuring units are secured to a support structure (12) comprised by a plurality of individual segments flexibly interconnected together in a two-dimensional array so as to be flexible about at least one axis. The measuring units may each be housed wholly or at least in part in a segment.

Description

OUTFALL MONITORING

This invention relates to a method of and apparatus for monitoring the outfall of discharge from both multi- port and open pipes and more particularly, although not exclusively, a method of and apparatus for monitoring outfall pipes used to discharge domestic and/or industrial effluent into aquatic environments, particularly the sea.

Prior proposals in this field have included such methods as visual observations from land, shore based radar (X band and UHF) and aerial photography. All these methods have the disadvatange that they collect information about an object without being in physical contact with it and are therefore subject to inaccuracies. They also have the disadvantage of not measuring the outfall in real time.

One object of the present invention is to provide an apparatus and method for monitoring the outfall of a discharge pipe in which the aforedescribed disadvantages are mitigated or overcome. Another object is to provide a monitor system and method which is reliable and may be of low cost.

According to the present invention apparatus for monitoring the outfall of a discharge pipe comprises at least one measuring unit provided at a submerged location and at least in part proximate an outlet of the discharge pipe, transmission means for transmitting a signal from the measuring unit, a transmission medium which conveys the signal transmitted by the transmission means and receiving equipment provided at an onshore site and responsive to a signal transmitted from said measuring unit.

The present invention also provides a method for _^"ιiϋnituj_ing the outfall of a discharge pipe comprising providing at least one measuring unit at a submerged location with at least a part of the measuring unit proximate an outlet of the discharge pipe, said measuring unit having associated therewith transmission means for transmitting a signal from the measuring unit via a transmission medium, providing receiving equipment at an onshore site and arranging said receiving equipment to be responsive to a signal transmitted from said measuring unit.

The onshore equipment may comprise a power generation unit which supplies power to one or each of a plurality of submerged measuring units.

The apparatus may comprise a number of measuring units for monitoring such parameters as velocity through an outlet diffuser, pressure within the pipeline, salinity, temperature, dissolved oxygen, ph and tide level and it is taught by the invention that these measuring units, or probes, may be provided at submerged locations in the water to lie at least in part close to or within the outlet at the discharge site. The units may transmit information via cable or radio signals to monitoring/logging/recording equipment which may be provided at the onshore site.

For efficient and reliable operation of that monitoring method and apparatus it is important that the monitoring units are protected from damage. It is also desirable that they be located in a manner which readily permits their removal from an underwater location.

By the present invention it is further provided that one or more monitoring units for location underwater are to be contained at least in part within a housing which is a segment of a plurality of segments flexibly interconnected together in a two-dimensional array so as to be flexible about at least one axis contained by the plane of the array.

A part of a monitoring unit may be contained by said housing, and another part may be located separate from said housing at a position proximate an outlet of a discharge pipe.

The segments may be flexibly interconnected by rope-like means such as a rope or hose or cable. At least one of the interconnecting members of the array may serve also as transmission means for the transmission of a signal from or to a monitoring unit.

Preferably the segments of the array are flexibly interconnected in a manner which permits their flexing relative to one another about two relatively inclined axes contained by the plane of the array. Each segment may be of, for example, a regular hexagonal shape as viewed in plan, rope means extending through opposite pairs of faces of each segment and corresponding faces of other segments of the array to provide three directions of interconnection and thus triaxial flexibility of the array.

Preferably each segment comprises a substantially hollow plastics shell. Some of the segments may be at least partly filled with a ballast material such as concrete to provide stability and prevent unwanted movement of the monitoring units.

Suitable segments and arrays thereof for use in the housing of parts of monitoring units are described for example in the specifications of GB Patent Publications 2156941 and 2212195, the arrays of segments described in those patent publications being adapted so that at least some of the segments are not wholly filled with ballast material and thereby are able to provide location for monitoring units. The segments for housing monitoring units preferably have open ends, such as an .open end 13 as shown in Figure 8 of GB 2156941A to facilitate required exposure of the monitoring unit to surrounding conditions.

The array of segments may alternatively comprise a plurality of parallel members interconnected so as to be flexible only in one direction. An example of such ~ structure is described in th specification of GB Patent Publication 2230314. The rectilinear tubes referred to in that patent application may be provided in their curved walls with appropriate apertures to enable a monitoring unit contained therein to be exposed to surrounding conditions .

It is particularly envisaged that a segment, such as a hexagonal shape segment or segment of other polygonal shape in plan for housing at least a part of a monitoring unit may be of a split shell construction, two shell portions being separable to facilitate access to a monitoring unit contained within the shell.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:-

Figure 1 shows an end of an outfall pipe and apparatus according to the present invention;

Figure 2 is a plan view of the segmental support structure of apparatus in accordance with the invention;

Figure 3 shows one of the segments of the support of Figure 2; Figure 4 is a vertical section of one of the segments of Figure 3 adapted to house in part a measuring unit, and Figure 5 shows schematically an outfall monitoring installation of the present invention. An outfall pipe 10 lying on the seabed 11 has placed thereover a flexible support structure 12 of a kind comprising a plurality of individual segments 13 flexibly interconnected together.

Figure 2 shows the manner in which the segments 13 are interconnected, and which is described in more detail in the specification of U K Patent Application GB 2156941A. Each segment is of a hexagonal shape in plan, as also shown in Figure 3, and is comprised

^■jj- a. iiϋiiuϊϊ p JL a. :_> X. X <— 0 auc i l .

Five of the segments 13" in Figure 2, are adapted to house in part a monitoring device. Figure 4 shows in cross-section one such segment shell and monitoring device 14. A small relatively robust part 15 of a monitoring device lies upwards of an aperture 16 in the shell, and the remainder including more delicate parts 17 of the monitoring device are contained within the shell. The robust part 15 is positioned in use to lie proximate but external of the end region of an outlet pipe. Within the shell is incorporated a transmitter for continuously transmitting to an onshore station a signal related to a parameter measured by the monitoring unit.

Figure 5 shows yet more clearly the overall apparatus of the invention in which the flexible support of Figure 2 is seen to be positioned solely at a remote end portion 18 of an outfall pipe 10 where at least one vertical riser 20 is located. The pipe extends to an onshore location 19 at which there is provided monitoring apparatus (not shown) for interpreting signals received from the monitoring units associated with the offshore support structure.

It is not essential that the monitoring equipment onshore is located in the vicinity of the outfall pipe. Thus it will be appreciated that the onshore monitoring function may be taken care of at a position remote from the path of the outfall pipe.

Claims

CLAIMS :

1. Outfall monitoring apparatus for monitoring the outfall of a discharge pipe comprising at least one measuring unit provided at a submerged location and at least in part proximate an outlet of the discharge pipe, transmission means for transmitting a signal from the measuring unit, a transmission medium which conveys the signal emitted by the transmission means and receiving equipment provided at an onshore site and responsive to a signal transmitted from said measuring unit.

2. Apparatus according to claim 1 and comprising a power generation unit which supplies power to one or each of a plurality of submerged measuring units.

3. Apparatus for monitoring one or more parameters in an aquatic environment comprising a plurality of segments flexibly interconnected together in a two- dimensional array so as to be flexible about at least one axis contained by the plane of the array and at least one of said segments housing at least in part at least one monitoring unit for monitoring, in use, a parameter of the aquatic environment.

4. Apparatus according to claim 3 wherein the segments are flexibly interconnected by rope-like means.

5. Apparatus according to claim 4 wherein at least one of the interconnecting members of the array serves also as a transmission means for the transmission of a signal from- or to a monitoring unit.

6. Apparatus according to any one of claims 3 to

5 wherein the segments of the array are flexibly interconnected in a manner which permits their flexing relative to one another about two relatively inclined axes contained by the plane of the array.

7. Apparatus according tc any one of claims 3 to

6 wherein at least some of said segments comprise a substantially hollow plastics shell.

8. Apparatus according to claim 7 wherein at least some of said shells are at least partly filled with a ballast material to provide stability and prevent unwanted movement of the monitoring units in use of the apparatus.

9. Apparatus according to claim 3 for monitoring the outfall of a discharge pipe and substantially as hereinbefore described.

10. Outfall monitoring apparatus according to claim 1 or claim 2 and comprising apparatus according to any one of claims 3 to 9 wherein said monitoring unit serves as the measuring unit recited in claim 1 or claim 2.

11. Method for monitoring the outfall of a discharge pipe comprising providing at least one measuring unit at a submerged location with at least a part of the measuring unit proximate an outlet of the discharge pipe, said measuring unit having associated therewith transmission means for transmitting a signal from the measuring unit via a transmission medium, providing receiving equipment at an onshore site and arranging said receiving equipment to be responsive to a signal transmitted from said measuring unit.

12. Method for the monitoring of a parameter in an aquatic environment comprising providing a plurality of segments flexibly interconnected together in a two- dimensional array so as to be flexible about at least one axis contained by the plane of the array, arranging a monitoring unit to be housed at least in part within one of said- segments and locating the apparatus at a selected position relative to the discharge pipe the outfall of which is to be monitored.

13. Method according to claim 12 wherein the flexible array of segments is positioned to lie over a discharge pipe and conform at least in part to the outer surface of that pipe.

14. Method according to claim 12 for the monitoring of outfall of discharge pipes and substantially as hereinbefore described.

15. Method for monitoring outfall of a discharge pipe according to claim 11 wherein said measuring unit is a monitoring unit as recited in any one of claims 12 to 14.