One of the most difficult applications in level measurement is Waste Water Management. When faced with unpredictable content and a challenging environment you need confidence in the durability of your instrumentation, making robust construction key for reliable data collection and asset integrity. This article will explore the key challenges faced by those in the Waste Water Industry, and explore solutions to such concerns.
Challenges in Waste Water Management
Contact with violently moving debris
Waste water management can be a violent application, capable of carrying heavy objects which can cause damage to level sensors. Features to cope with this environment include:
- Fully welded construction in stiff titanium or tough stainless steel
- Injection molding of the electrical cable to the sensor body ensures the IP68 rating is maintained, guaranteeing the integrity of the sensors
- Thick cable walls made of tough polyurethane or stiff chemically robust Hytrel
- Kevlar cable core supply strength – preventing cable stretching
The risk of silting is reduced by connecting the pressure sensing element to the media through a carefully designed pressure port. Soft nose cones both protect the sensing element from physical shock damage and are easily removed, allowing access to the open face connectors that enable gentle cleaning in extreme circumstances.
No power available
When it comes to waste water management, power is a key concern. Experts recognize the need to minimize the requirements for expensive batteries or solar chargers. Piezo-resistive sensing elements and analogue electronics enable pulse power operation, with readings taken in as little as 10 ms. This significantly reduces energy consumption. Voltage outputs reduce current consumptions to a few mA and in short cable run applications, mV output sensors reduce the power on time and current consumption even more.
Waste water can release explosive methane. This means that many chambers are designated as hazardous areas. Products used in these areas need to be certified as safe for use. BHGE pressure sensor products carry an array of certifications for use in such areas allowing installation using different safety rules to suit the application and validity in most countries around the world.
Titanium or stainless steel metal work with polyurethane or Hytrel cable can be chosen to reduce the risk of chemical corrosion damaging sensors.
Blocked line of sight and surface foaming
By measuring the pressure at depth in order to calculate level, BHGE Pressure based level sensors are immune from incorrect readings caused by obstruction in tanks or chambers as well as surface debris or foaming that will cause errors in line of sight based devices like ultrasonics or radar.
Used in areas of low pressure
Many waste water applications are in shallow drains where the level of water in normal conditions is very low. BHGE pressure sensors use silicon sensing elements made in our own state-of-the-art clean room facility in Leicester, UK. In order to enable highly sensitive low pressure measurement, particularly in large surface areas, thin elements are used. This makes it possible to measure pressures with a full scale reading as low as 0.7 mH2O (70 mbar, 1 psi).