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Aprodit Ltd.
Russia, Moscow Region,
Kolomna, Oksky prospect, 40
+7 (999) 845-19-75 (English)

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Electromagnetic Locators NPR
  The PNT-NPR system for tracking and tracing of cleaning PIGs inside pipelines / El sistema PNT-NPR de localizacion y rastreo de diablos de limpieza de interior de tuberias

Low-frequency electromagnetic receiver-registrator (or briefly locator) NPR is a portable device for registration of signals from any 22Hz transmitter installed on an in-line PIG. Also it is used to determe exact position of the PIG with transmitter inside a pipeline.

The locator also detects changes of weak magnetic fields. So it is possible to register a passage of a PIG even without transmitter when it moves inside a pipeline and introduces small changes in the Earth magnetic field in the vicinity of the pipeline.

Electromagnetic signal from a transmitter emitted on frequency 22 Hz can pass through metallic wall of a pipeline, through walls of receiving or launching chamber, through metallic or ferroconcrete walls of reservoirs and also through soil or water above burried or offshore pipelines.

When useful signal from a transmitter is registered by NPR receiver then operator is informed by sound and by LED indication on the receiver's front pannel.

The locator has high sensitivity and narrow frequency band. It enables to register the signal from a transmitter even in rugged or difficult environments like man-made electromagnetic noises with 50 or 60 Hz frequency as well as in deep pipeline bedding.


Receivers (locators) NPR of various modifications have the same management interface and unified electronic components as well as algorithms. All controlling functions are activated by pushing 2 buttons on the front panel (or on side surface of NPR-03).

For visualization of the received signals and for alerting the operator there are LEDs on the front panel which work very reliably at any temperature and lighting conditions. The receivers NPR-00 which are not intended to work under water have built-in speaker that sound alerts to the operator about received signals.

To carry receiver NPR-00 and for convenient work with it there is a fold-out handle. If NPR-01 is ordered with external antenna and a cable length is more than 30 m, we will offer a special bollard for easy and fast laying / winding the cable. The ergonomics of the underwater logger NPR-03 was thought out for convenient operation of a diver, as well as to enable control of this receiver by the manipulator of underwater vehicle (ROV).

Receiver NPR-00
This low-frequency receiver has an infrared port for remote control of transmitters PNT, a recorder of magnetic field changes, as well as an external speaker. It can automatically register up to 5 passes of PIG with a transmitter or magnet.

More detailspdf

Receiver NPR-01 with external antenna
The receiver is equipped with a connector to plug-in cable of external antenna (suitable for marine applications and with cable length up to 200m) as well as for connection to a computer via a USB port for transferring of recorded signals. NPR-01 also can be used as above ground marker for the benchmarking during an in-line inspection of a pipeline.

More detailspdf

Underwater receiver NPR-03
NPR-03 receiver has a robust housing that can withstand external pressures up to 30 MPa. It was designed to work near underwater pipelines which laid at a depth of up to 3 km. It can be controlled via underwater vehicle (ROV). Also It may be used by a diver.

More details pdf

On customer request, we are ready to make some changes in the design of our serial receivers NPR to meet specific needs and to achieve possibilities for use of these receivers in some specific conditions.


Receivers NPR have been certified for compliance with the requirements concerning explosion protection TR TC 012/2011 at the Center for Certification TekhnoProgress. Previously the receiver-recorders (locators) NPR were sertified in GOST R system by NANIO CCVE, which is the only Certification Centre in Russia accepted in the IEC Scheme.

Receivers NPR are designed for work in explosion-prone areas and outdoor facilities according to the following international and Russian normative documents regulating application of electrical equipment in hazardous areas:

Ex-certificate TR TS 012/2011 "On the safety of equipment for use in potentially explosive atmospheres" for the low-frequency receiver-recorder NPR


A certificate about inclusion of receivers NPR into the register of the devices recommended for use in energy companies, issued by the Certification Centre of Russian State University of Oil and Gas named after IM Gubkin.

  • IEC 60079-11-99 Electrical apparatus for explosive gas atmospheres. Part 11. Intrinsic safety i.
  • GOST 22782.3-77 Explosion proof electrical apparatus. Special construction. Technical requirements and methods of testing.
  • IEC 60079-12-78 Explosion protected electrical apparatus. Part 12. Classification of mixtures of gases or vapours with air according to their maximum experimental safe gaps and minimum igniting currents.
  • IEC 60079-10-95 Electrical apparatus for explosive gas atmospheres. Part 10. Classification of hazardous areas.
  • IEC 60079-0-98 Explosion proof electrical apparatus. Part 0. General requirements.
  • IEC 529-89 Degrees of protection provided by enciosures (IP Code) .
  • and other normative documents regulating the use of electrical equipment in hazardous areas.

Certification of NPR receivers in accordance with GOST R standards was accomplished in 2007.

Since 2012 NPR receivers are listed in the Register of technical devices, recommended for use in enterprises of fuel and energy complex of the Russian Federation.

In 2013 for receivers NPR Certificate 012/2011 On safety of equipment intended for use in explosive atmospheres was issued. This certificate of conformity to the technical regulations of Customs Union is a document certifying the conformity of the transmitters to the set of technical international regulatory documents and allowing use of certified products on the territory of Russia, Belarus and Kazakhstan without any evaluation procedures or additional requirements.

Special explosion-proof mark Ex (in accordance with Annex 2 to the technical regulations of the Customs Union "On the safety of equipment for use in potentially explosive atmospheres" (TR TC 012/2011)

Special sign EAC about free circulation of the products on the market states - members of the Customs Union

Special mark on certification in the Russian GOST R system

Logo of autonomous non-profit research organization Center for Certification of explosion-proof and Mining Equipment NANIO TSSVE

Logo Gubkin Russian State University of Oil and Gas

Logo TEKSERT system of voluntary certification of fuel and energy complex, created in the Russian State University of Oil and Gas named after IM Gubkin, in accordance with Art. 21 of the Russian Federal Law of 27.12.2002  184-FZ On technical regulation.

Logo of explosion proof equipment certification center TekhnoProgress

Low-frequency receivers NPR are produced in numbers in accordance with Tecnical Conditions TU 4276-001-96335610-2008

The devices have explosion protection label 1ExibIIBT3X and Ingress Protection class IP68 according to IEC 529-89

The manufacturer gives warranty of 12 months for all receivers NPR.


Receivers NPR register the signals from different transmitters operating at frequency 22Hz, such as the PNT, CD42, ITX, PC1, PN, etc. The signal from PNT transmitter is detected by NPR locator in air at distance of 25 meters. With NPR it is also possible to register the passage of a PIG without transmitter (with metal housing or equipped with a magnet).

The received signal passes a complex analog and digital processing. In the presence of electromagnetic oscillations with frequency 22 Hz an audio alert is sent to operator by built-in speaker.

To monitor the signal strength there is linear LED indicator on the front panel of the locator, which allows working at temperatures ranging from -40C to +60C in any lighting condition, including the bright sun. LED brightness is automatically adjusted.

Used in the device circuit and mechanical design solutions allow to work in a variety of climatic conditions and in hazardous areas of Class 1, 2 in which the formation of explosive mixtures of IIB category and temperature group T3 is possible.

Managing of the locator was simplified and made intuitive. All modes and switch from one mode to another are described in the instructions that came with the delivery set. Instructions are written in English (and by demand in Russian) languages.

For additional convenience, a 10-minute Video showing how to use NPR locators and PNT transmitters was downloaded on YouTube.

Convenient carrying bag (or robust plastic case by request) is included in the delivery set.




NPR-01 and NPR-03 receivers can be used as above ground markers (AGM) during in-line inspection of a pipeline with a GPS coordinates reference (benchmarking technology). For this purpose locator has a high-precision built-in quartz clock which can be preliminarily synchronized via computer with the clock in the inspection PIG.

Also NPR locator has an electronic module which registers changes of weak magnetic fields. This module allows to detect a passage of a PIG, even if it is not equipped with an electromagnetic transmitter. It's enough that the PIG is made of ferromagnetic materials (ordinary steel) or was equipped with a small permanent magnet. In this case, the passage of the PIG will change Earth's magnetic field in the vicinity of the pipeline, and it will be registered by the locator.

Additionally, an electronic module with infrared (IR) transmitter is embedded into NPR-00 locator housing. This module is used for remote control of PNT transmitters. So there is no need to remove PNT transmitter from a PIG or disassemble it in order to turn it off or change the mode of emission. It can be done remotely.

Managing of PNT transmitter via IR channel is shown in the video instruction.



Widely used AA batteries (manufactured by DURACELL, Energizer, etc.) are used as power supply for the locator. Batteries are easily replaced.

Low current consumption and the availability of indicator showing batteries charge level allows to use the batteries up to complete discharge. Time of autonomous work for NPR locator is not less than 240 hours.

Lithium batteries with voltage 1.5V (Energizer, Ultimate Lithium, AA, 1.5V) ensures long life and reliable operation of the locator at temperatures down to minus 40C.

NPR locator is designed for work for many years, requiring only periodical replacement of batteries.

Manufacturer: APRODIT Ltd.
140402, Russia, Moscow region, Kolomna, Okskiy prospect 40.
Have a question? Please contact us by phone +7 (916) 674-82-59 (English) or by e-mail