FR2681124A1 - Device for detecting leaks in buried structures for storing or conveying sulphuric acid by pipeline - Google Patents

Abstract

Device making it possible to detect leaks in buried structures for storing or conveying sulphuric acid. It consists of a conduit produced with pipe units assembled using T couplings in which the side orifice is shut off by a zinc closure flap. Installed in the same trench, at the depth of the lower generatrix and beside the structure to be monitored it is provided at each end with a manometer (1), a flowmeter (2), an electrical signal generator (3), an electrical threshold voltage limiter (4) and a siren (5). It is connected to a pressurised water system. In the event of leakage the acid perforates the closure flap, producing a flow measured by the flowmeters. The measurements are transmitted to the generator and then to the electrical voltage limiter which triggers the alarm in the case of the displayed flow threshold being exceeded.

Description

The present invention relates to a device for detecting leaks in underground structures of trans
port by pipeline or storage of sulfuric acid. Existing leak detection devices,
developed for non-corrosive fluids, are or expensive because of the equipment required or unsuitable
in the case of sulfuric acid due to: either the corrosive nature of the fluid for the materials constituting the specialized sensors and scrapers brought into direct contact with the acid, or the material constituting the
channeling which quickly attenuates the sounds emitted by the leak. The device according to the invention makes it possible to
detect leaks of sulfuric acid in a simple way and at a reasonable cost.The device is based
on the chemical reaction of the attack of zinc by sulfuric acid:
H2S04 + Zn ---- ZnS04 + H2
The detection device is constituted according to a first characteristic by:
- a small section conduit made of material resistant to the corrosive action of acid produced with ele
tube elements assembled to each other by T-fittings whose lateral orifice is closed by a
zinc cover attackable by sulfuric acid.

- control and alarm triggering equipment consisting of a pressure gauge and a flowmeter
be coupled with audible or (and) visual alarm equipment.

- connection fittings to a city or industrial water network or other water reserves under
pressure.

The conduit is installed in the same trench, at the depth of the lower generator of the cana
reading to be monitored, parallel to and next to it so that a Tee with its zinc cover
either opposite each point at risk of spreading acid. To improve acid collection, a sheet
of plastic or other materials insensitive to the action of acid is placed at the bottom of the trench under the
pipeline and the conduit at each of these risk points.

 Once in place and connected to the water network, the pipe is pressurized.

In the absence of a leak, the measuring instruments indicate a zero flow and an identical static pressure
at both ends. In the event of leakage and spreading of acid, the latter attacks and punctures the seal in
zinc. The perforation of Operculum results in the establishment of a water flow which is reflected
towards the ends of the conduit activating the flowmeters. The measured flows are transmitted to the equipment
alarms. When the measured water flows exceed a displayed threshold, the audible or (and) visual alarm is
activated.

The accompanying drawings illustrate the invention:
- Figure 1 shows the control and alarm triggering equipment consisting of a mano
meter (1), a flow meter (2), an electrical signal conditioner (3), a voltage threshold limiter
electric (4) and an audible alarm (S). The apparatus is identical at both ends of the conduit.

- Figure 2 shows the layout of the tee fitting relative to the pipe.

- Figure 3 shows in section, the location of the conduit at the bottom of the trench
- Figure 4 shows in section, the tee fitting according to the invention.

With reference to these drawings, the T-fitting shown in FIG. 4 includes a tarau tightening cap.
thimble (6), the bottom of which is drilled and provided with a groove for holding an O-ring (7) ensuring the propane
cheerfulness. The hole in the cap serves as a centering housing for the zinc cover (8), a sensitive die element
tection attackable by acid. An intermediate washer (9) placed between the cover and the threaded end of the
Tee connector (10), used to compensate for flatness defects during tightening.

The device according to the invention is intended to detect leaks in buried structures for storage or
transport by pipeline of sulfuric acid. Its use can be extended to other fluids in rem
placing the Popercule in zinc with another material degradable by the fluid in question.

Claims (3)

1) Device for detecting leaks in buried pipeline or storage structures  sulfuric acid characterized in that it consists of a conduit composed of elements of tubes  assembled by means of T-fittings, the lateral opening of which is closed by a zinc cover. This  conduit is provided at each end with an apparatus for controlling and triggering alarms constituted by a pressure gauge (1), a flow meter (2) coupled to an electrical signal conditioner (3) which is connected to  an electrical voltage threshold limiter (4) which is provided with electrical contactors for the communication  requests audible (5) or (and) visual alarms.  2) Device according to claim 1 characterized in that the tee fitting has its blocked side orifice  by a clamping cap (6) provided with a groove for holding an O-ring (7) and an orifice  serving as a housing for a zinc cover (8) and an intermediate washer (9) intended to compensate for the  flatness defects.  3) Device according to claim 1 or claim 2 characterized in that the active part of detection  tion is a zinc cover (8).