PEK-KNI floor electrode JOLA

Description

The PEK-KNI JOLA floor electrode signals via an electrode relay the presence of a liquid medium due to, for example, a burst pipe. Floor electrodes are designed for use in dry rooms.

PEK-KNI with integrated galvanic separation:

• prevents interconnection of electrode circuits
• prevents the formation of earth loops when more than one detector is connected to a common power supply circuit.

Conductive plate electrodes PEK -… must only be used in normally dry environments. They should be installed on the ground with the sensor side facing down and the label facing up.

The conductive plate electrode PEK -… is equipped with two separate electrodes in the form of two electrode plates: 1 control electrode and 1 earth electrode. As soon as the conductive liquid creates a conductive path between the two electrode plates, the switching state of the leak detector changes.

Conductive measurement principle

The principle of conductive measurement is used to detect electrically conductive liquids. Not suitable for the detection of electrically non-conductive liquids.

Electrically conductive liquids are usually aqueous solutions of salts, acids or alkalis. In water, the molecules of these substances separate into positive and negative ions, which give the aqueous solution its electrical conductivity. A conductive leak detector detects the presence of an electrically conductive liquid and an alarm is then sounded.

The measurement process uses alternating current to ensure accurate response sensitivity and to prevent galvanic processes at the electrodes. The conductive leak detector shall have an integrated electronic evaluation unit with galvanically isolated circuits. This prevents the electrode circuits from interconnecting and forming earth loops if more than one of these leakage detectors is connected.

Reliable detection of liquids with poor electrical conductivity, such as condensate or demineralised water, is ensured by the factory-set sensitivity response of the conductive leak detector.

PEK-KNI features

• Design: leak detector with evaluation electronics as initiator for NAMUR circuit
• electrode plates: 2 316 Ti stainless steel plates, each 24 mm in diameter
• Housing: PP and cast resin
• electrical connection: two-wire connection via 2 x 0.75 connection cable, 2 m long, longer connection cable on request; halogen connection cable on request
• supply voltage: only for connection to extra low voltage SELV or PELV! (see datasheet)
• output signal: impressed current signal in the power supply circuit
• operation: quiescent current principle
• switching state in case of cable break: I < 0.2 mA
• switching condition both sensing capacitors are activated: I ≤ 1 mA
• switching condition both sensing capacitors are not activated: I ≥ 3 mA
• switching status in case of short circuit or wrong polarity: I > 6 mA
• galvanic isolation: only for connection to extremely low voltage SELV or PELV! voltage resistance > 500 V between capacitor circuit, supply circuit and output circuit
• max. no-load voltage across the sensing capacitors: 5 Veff 15 kHz (safety extra-low voltage SELV)
• max. short-circuit current on sensing capacitors: 0.2 mA
• response sensitivity: approx. 30 kΩ or approx. 33 μS (conductivity)
• temperature range: – 20 °C to + 60 °C

For more technical information, please refer to the datasheet attached under the Documentation tab.

Example of PEK-KNI use: monitoring false floors in a server room using a cable electrode and a panel electrode in an adjacent room.

Welcome to the article ”Conductive Measurement of Liquids”