DE4029186A1 - Monitoring system for waste water channels - electronically detects waste water escaping from and ground water entering pipes using pulse echo measurement - Google Patents

Abstract

The monitoring system detects waste water and/or ground water electronically using a pulse-echo measurement device and detection line so that the leakage positions are detected and located immediately. The detection line is in the form of an optical conductor. The system can be used as a separate safety and protection system. USE/ADVANTAGE - For continuous leak monitoring of waste water pipes operated in no-press. mode. Achieves immediate detecting of waste water leakage, and hence environmental danger, and of ground water entering waste water system, thus raising operating costs, enabling corrective measures to be taken.

Description

The invention is concerned with a continuous Control and monitoring system for the tightness of pipes Sewers that operate in the free-level gradient will.

In recent times, the knowledge about the Pollution in the environment is constantly increasing. These Findings are diverse and relate to one considerable number of technical areas with each different hazard potential. Such a Area is z. B. the danger to groundwater and soil through leaky sewers. Although the type and scope of the existing soil and groundwater contamination at the moment cannot be estimated exactly yet Danger potential from the professional world as "considerable" classified.

As a result of this, protection of the Groundwater legal regulations and technical Rules for the relocation of sewers in water management priority areas (drinking water protected areas). In these s.g. Special provisions is basically between the two in technical terms differentiated between the following types:

Laying the sewer in a sealed protective tube (Double pipe system)

 The double pipe system is to be constructed in this way form that any leakage water in the annulus between Protection and sewage pipe unhindered to the next Control shaft can be derived. In the later  Repeated pressure tests must be provided for operation. The inspection shafts are inspected every six months to undergo control.

Laying of single-walled sewers under consideration special technical requirements (single pipe system)

 This type of design has increased requirements the pipe tightness (pressure tests according to pressure pipe criteria with 2.4 bar overpressure) and to the pipe static dimensioning (Increase in the safety factors). Furthermore these channels must be designed so that later Repeat pressure tests carried out at any time can be. As an appropriate test cycle, two viewed up to five years.

In the aforementioned types of execution for the Execution of the later repeat pressure tests sufficiently large storage tanks (unless otherwise extensive diversion options exist) the wastewater generated during the pressure test to be able to hold back. In both cases (at consistent handling of the regulations) the financial Expenses for the additional facilities are therefore considerable. In both cases, the time recording is one possible leakage and thus the possible underground contamination depending on the interval times in the Operation carried out visual checks and / or the Result of the repeat pressure tests. It can be easy several years pass before a leak is detected. A disadvantage of the systems in use is that a continuous control or permanent Monitoring the pipe tightness of the sewer at the moment. Not given is. Knowing this, Control and monitoring system described below invented for sewers. This surveillance system  enables the immediate detection of a leak from small and smallest amounts of wastewater as well as the same Timely determination of the location of the damaged area in the wastewater channel.

The monitoring system is an independent safety and protection system which is introduced into the sewage pipe in the form of a partial lining ( FIG. 1). It consists of a plastic drainage mat that is closed on all sides and attached to the inside of the pipe in a half-shell shape. A detection line is arranged within this drainage mat in the bottom area, via which a corresponding signaling system is activated in the event of a wastewater or groundwater intrusion.

The drainage mat can be used from a design point of view, for. B. made of plastic tubular films or double-layered Foil sheets with pressure-stable inner profiles (as a drainage zone) exist. Are also on the Coated plastic parts are possible.

To this drainage mat and detection line (in the following Called primary system) before mechanical and / or hydraulic To protect stresses wear-resistant plastic half-shells (in the following Called secondary system) so that any Backwashing and / or signs of buoyancy prevented will. These half shells can be used in constructive and material view so that the degree the mechanical, physical, chemical, biological and corrosive stress as well as the local installation conditions are taken into account. The half shells are at Interchangeable.

Since the sewers are usually also for the Rainwater runoff is dimensioned partially clothing up to about 50% pipe cross-section as a rule  reaching. The operating times above 50% pipe cross-section are very small. Reduced security (such as it is also approved in the technical guidelines) to be accepted. The sewers in question are anyway in accordance with the applicable technical rules additional reserves in the drainage capacity dimension. This increases the operating times half 50% pipe cross section reduced again.

In the event of a claim, two possible types of damage are possible differentiate:

• 1. The primary system is damaged from the inside of the pipe ( Fig. 2).
  This case of damage occurs when the secondary system and the upper layer of the primary system have not withstood the existing stresses. In this case, the sewage pipe itself is not yet damaged. The reporting system is activated when wastewater enters the primary system. The sewage pipe offers protection against wastewater exfiltration.
• 2. The primary system is damaged from the outside of the pipe ( Fig. 2).
  This damage occurs if the sewage pipe has not withstood the external or earth static loads (subsidence, traffic loads etc.) and has been damaged as a result. However, the damage must be so considerable that the lower layer of the primary system (which is fixed to the inside of the pipe by means of adhesive technology) was also damaged due to overstretching.
  With regard to the location of the pipe bottom to the groundwater level, two options are distinguished.
  • a) Pipe bottom below the local groundwater:
    The reporting system is activated by the entry of groundwater (groundwater detection) into the defective primary system.
    The top layer of the primary system and the secondary system provide protection against wastewater exfiltration.
  • b) Pipe bottom above the local groundwater:
    The signaling system is activated when the lower and the upper layer of the primary system have been damaged at the same time and the wastewater (wastewater detection) can exfiltrate into the ground at the pipe break point.

When looking at these damage patterns it becomes clear that the invention is not just a continuous one Control and monitoring system, but also simultaneously for additional, separate and relatively flexible protection system acts.

The reporting system only applies to the damage pattern under 2b) only activated when both systems (channel and protection system) are damaged. Due to the location of the canal outside of one Groundwater zone as well as by the immediate detection of even the smallest amounts of wastewater with simultaneous location This limitation can be determined by determining the pipe break point however, to be accepted.

The alarm system consists of a in the drainage mat installed detection line and a pulse-echo measuring device, a fault alarm system when detecting measurement deviations activated. The location of the measuring device can be at the end point of the Sewer in the sewage treatment plant or in a shaft with Telecommunications connection.  

Wire pairs without protection are used as the detection line insulation or fiber optic cables with moisture sensitive coating (swelling substance) provided. Through the the light guide becomes mechanically moistened claimed, whereby the optical properties change that this from the v.g. Pulse-echo measuring device recognized can be.

The advantages achieved by the invention are special in that wastewater exfiltration (and thus Environmental hazards) and groundwater infiltration (and thus increased operating costs for wastewater treatment) can be recognized immediately and therefore appropriate steps be taken in good time to minimize damage can. The operators of sewers with this control and monitoring system - contrary to the previous one Situation - overview of the current status of your channels with regard to operational safety and environmental hazard potential. In addition to reducing and controlling The aforementioned invention leads to potential risks also to a cost saving in the ratio of the current in Design types used in sewer construction.

Claims (3)

1. Control and monitoring system for sewers, characterized is that the detection of waste water and / or groundwater is carried out electronically by means of pulse-echo measuring device and detection line, wherein the leakage point immediately determined or located. 2. Monitoring system according to claim 1, characterized that an optical conductor is used as the detection line becomes. 3. Monitoring system according to claim 1, characterized in that the surveillance system at the same time as a separate Security and protection system is used.