LMK458 Marine Approved Hydrostatic Level Transmitter

Marine approved level transmitter with 4-20mA current loop output for measuring the level of contents inside a ships ballast, fuel, liquid cargo or wastewater tanks with optional all CuNiFe construction for sea-water compatibility in ranges from 0.4 mH2O to 200mH2O gauge or absolute.

The LMK 458 marine level transmitter has a capacitive ceramic sensing diaphragm which is compatible with sea water and salt spray when the copper nickel alloy option is specified.

The LMK458 marine level transmitter is Germanischer Lloyd (GL) and Det Norske Veritas (DNV)approved for marine use and can be used on seawater ballast, fuel, oil, service and waste water systems.

ATEX approved for intrinsically safe use in hazardous environments the LMK-458 marine approved level transmitter can also be used on ship systems which are handling flammable and volatile chemicals such as oil, gas, liquid petroleum gas (LPG) and liquid natural gas (LNG).

The LMK-458 ballast level sensor comes in a range of pressure fittings for either lowering into a tank, screwing into a pipe or flange mounting to the wall of a tank.

Product Parameters

• Pressure Ranges: 0.4 up to 200 mWG, 40mbar to 20 bar gauge or absolute
• Accuracy: 0.25% full scale with optional 0.1% for ranges above 6mH2O only
• Output Signal: 4-20mA current
• Electrical Connection: IP68 submersible TPE cable outlet
• Pressure Connections: flange or screw-in with flush diaphragm
• Media Compatibility: Stainless steel 316L or CuNi10Fe1Mn body, Ceramic Al2O3 (96%) diaphragm, FKM, FFKM or EPDM seal gasket plus selected cable jacket
• Dimensions: 39.5 mm diameter
• Weight: 650 g minimum
• Special Features: DNV & GL marine approved for use on ships ballast, fuel and liquid cargo tanks
• Special Options: CuNi10Fe1Mn construction for seawater use, ATEX IS approval, prepared for pipe mounting, integrated PT100 temperature sensor, HART communications

Product Description

The harsh corrosive environment which level sensors are subjected to on a ship, call for a corrosion resistant construction and robust mechanical design.

The materials employed need to withstand the effects of relentless exposure to seawater and salt spray when installed on the deck or in the ballast tanks of a ship. The design must meet the mechanical integrity requirements for pressure measurement and be robust enough to survive in an uncompromising heavy industry environment.

The LMK458 tank level transmitter measures the hydrostatic pressure of a wide range of liquids that are found on marine vessels such as oil tankers and bulk carriers.

Installation types

This versatile marine approved hydrostatic level transmitter has many different styles for mounting, starting with the simplest which involves dropping the LMK-458 level transmitter down a stilling well to measure the level whilst permanently submerged in the tank. This is useful for installations where there is no service access to the side of the tank.

If a stilling well is not available, the submersible level transmitter has a mounting bracket option for fixing into position on the inside of the tank.

Where maintenance access between tank bulkheads is possible the LMK 458 marine level transmitter can be mounted with a G11/2 male thread or with a flange mountable fitting.

Sea water compatibility

For seawater systems the LMK-458 ballast level transmitter can be made from Copper Nickel alloy construction which has high corrosion resistance to sea-water and can be used on ballast tanks and other seawater pumping systems.

Hazardous cargo

If the vessel is carrying hazardous material which requires IS approved instrumentation such as oil tankers, LPG ships or LNG ships, the LMK 458 level pressure transmitter can be supplied with ATEX approval for intrinsically safe use.

Flush chemical resistant diaphragm

The LMK458 marine approved hydrostatic level transmitter incorporates a capacitive ceramic sensing diaphragm that has a high overpressure. This is useful for cargo ships which carry a variety of chemicals and need to clean the inside of the tank with high pressure caustic solutions.

The flush ceramic diaphragm is also well suited for use with waste water, abrasive material, viscous fluids and corrosive chemicals because of the hardness and inert properties of alumina ceramic.

Marine approved

For added assurance of the LMK458 hydrostatic pressure transmitters suitability for use in shipbuilding applications it has been certified by Germanischer Lloyd (GL) and Det Norske Veritas (DNV) for marine use.

Level measurement

The LMK-458 marine approved level transmitter can measure hydrostatic pressure from 0.4 up to 250 metres of water gauge with an accuracy of ±0.175% full scale best straight line non-linearity, hysteresis and repeatability. The capacitive ceramic sensor provides a high overpressure rating as much as 10 times for some ranges which helps protect the sensor from surge pressures when the tank is being filled or cleaned.

Multi-purpose

Shipbuilders require flexibility, high reliability and corrosion resistance from the instrumentation they install and the LMK458 level transmitter has been designed for this task with many possible configurations for most level measurement applications onboard a sea vessel.

Product Applications

Marine vessel tank level

• Diesel fuel
• Fresh water
• Grey water
• Black water
• Sea water ballast
• Liquid cargo

Oil tanker ballast

Large oil tanker ship ballast tanks up to 30 metre depth.

• SKU ID: s1-lmk458-0006
• Part No: 765-3001-K-1-2-E-1-4-2-040-000
• Pressure Range: 0 to 30
• Units: mH2O
• Reference Type: Gauge / Vented (atm to +P)
• Output Signal: 4 to 20 mA, 2 wire
• Accuracy: 0.25% FS
• Installation Type: Probe version with nose cone
• Housing Material: Copper Nickel Alloy (seawater compatible)
• Diaphragm Material: Ceramic Al2O3 96%
• Media Exposed Seals: FKM
• Cable Type: TPE (125degC max)
• Cable Length: 40
• Cable Length Units: Metres (m)
• Optional Extras: ATEX Intrinsic safety approval

Sea vessel fuel oil tank hydrostatic pressure & temperature

Measure hydrostatic pressure and temperature of fuel oil tanks vented to atmospheric pressure on a sea vessel. Lower the sensor inside the fuel oil tank and suspend from the cable gland flange assembly fitted to the top of the tank.

• SKU ID: s1-lmk458-0008
• Part No: 765-4000-1-1-2-E-1-4-2-006-013 / DN25
• Pressure Ran ge: 0 to 0.4
• Units: bar
• Reference Type: Gauge / Vented (atm to +P)
• Output Signal: 4 to 20 mA, 2 wire
• Accuracy: 0.25% FS
• Installation Type: Probe version with nose cone & assembly flange
• Housing Material: Stainless Steel 316L
• Diaphragm Material: Ceramic Al2O3 96%
• Media Exposed Seals: FKM
• Cable Type: TPE-U (125degC max)
• Cable Length: 6
• Cable Length Units: Metres (m)
• Optional Extras: ATEX Intrinsic safety approval
• Optional Extras: PT100 integral temperature sensor
• Optional Extras: DN25/PN40 assembling flange with cable gland

Oil platform concrete leg

Measure the level of seawater in the concrete leg of an offshore oil production platform.

• SKU ID: s1-lmk458-0009
• Part No: 765-2501-K-1-2-E-1-4-2-050-000
• Pressure Range: 2.5
• Units: bar
• Reference Type: Gauge / Vented (atm to +P)
• Output Signal: 4 to 20 mA, 2 wire
• Accuracy: 0.25% FS
• Installation Type: Probe version with nose cone
• Housing Material: Copper Nickel Alloy (seawater compatible)
• Diaphragm Material: Ceramic Al2O3 99.9%
• Media Exposed Seals: FKM
• Cable Type: TPE-U (125degC max)
• Cable Length: 50
• Cable Length Units: Metres (m)
• Optional Extras: ATEX Intrinsic safety approval

Product Help

Encapsulated with no external controls

Are all the electronics are encapsulated within the sensor with no external controls?

Yes on the the standard LMK 458 all the electronics are internal to the sensor, and everything is fixed with no access for adjustment.

If you want a sensor that has a user adjustable output, we would suggest the LMK458H HART communications version, which allows you to connect a HART communication device to the 4-20mA analogue signal wires in order to communicate with the sensor and make adjustments.

Cable compatibility

What types of liquids found on a ship are compatible with the sensor cable?

The standard TPE-U cable supplied with the LMK 458 is resistant against salt water, sea water, heavy oil and has increased resistance against oil and gasoline.  The cable is also flame-resistant and halogen free.

Range adjustment

Is it possible to adjust output and to measure a different liquid level range?

The standard LMK458 has a factory set fixed range output which cannot be to re-scaled by the user to a lower range. However, it is possible with the derivative LMK458H, which can be rescaled to a maximum turndown of 10:1 via the HART communication interface. You will also need a universal HART communicator in order to access and adjust the range settings.

Cable diameter

What is the diameter of the cable?

The cable diameter is 7.4mm

Cable bend radius

What is the bend radius of the cable?

A minimum static bending radius has to be complied with. For static installation rhe bend radius should be no smaller than 10 times the cable diameter. For dynamic applications the bend radius should be no smaller than 20 times the cable diameter.

Ship hull diesel fuel tank level

I have a marine vessel application where I need to measure the diesel fuel level via hydrostatic pressure in a non-symmetrical tank which is made up from voids in the ships hull that are linked together and act like a fuel tank. The tank holds approximately 8600 litres of diesel fuel oil.  Would the LMK 458 level transmitter be capable of meeting these needs, and does it matter if the tank is vented or not vented?

Yes the LMK 458 will work for the application you have in mind, but whether the tank is vented or not, will matter to how many sensors you need and the measurement range:

• Vented Tank – If vented then you can use a single sensor to measure the hydrostatic pressure.
• Non-Vented Tank – For a non-vented tank you would need to measure using two sensors one at the bottom and one at the top and subtract the two readings to determine the hydrostatic pressure.

LMK 457 replacement

Is the LMK458 the replacement for the LMK457?

Yes the LMK457 is no longer available and has been replaced by the LMK 458.  If you are looking to replace the LMK457 you can send us the part number and we will convert it to the equivalent LMK458 part number for you.

760-1601-K-1-2-1-3-4-3-008-000

What is the specification for the LMK457 part number 760-1601-K-1-2-1-3-4-3-008-000?

The LMK457 is obsolete and has been replaced by the LMK458, and the like for like new part number & spec is as follows:

• SKU ID: s1-lmk458-0005
• Part No: 765-1601-K-1-2-1-3-4-2-008-000
• Pressure Range: 1.6
• Units: bar
• Reference Type: Gauge / Vented (atm to +P)
• Output Signal: 4 to 20 mA, 2 wire
• Accuracy: 0.25% FS
• Installation Type: Probe version with nose cone
• Housing Material: Copper Nickel Alloy (seawater compatible)
• Diaphragm Material: Ceramic Al2O3 96%
• Media Exposed Seals: EPDM
• Cable Type: TPE (125degC max)
• Cable Length: 8
• Cable Length Units: Metres (m)

760-1001-K-1-2-1-3-4-3-005-000

What is the equivalent LMK458 spec for an old LMK457 part number  760-1001-K-1-2-1-3-4-3-005-000?

• SKU ID: s1-lmk458-0003
• Part No: 765-1001-K-1-2-1-3-4-2-005-000
• Pressure Range: 1
• Units: bar
• Reference Type: Gauge / Vented (atm to +P)
• Output Signal: 4 to 20 mA, 2 wire
• Accuracy: 0.25% FS
• Installation Type: Probe version with nose cone
• Housing Material: Copper Nickel Alloy (seawater compatible)
• Diaphragm Material: Ceramic Al2O3 96%
• Media Exposed Seals: EPDM
• Cable Type: TPE (125degC max)
• Cable Length: 5
• Cable Length Units: Metres (m)

120°C fuel

Is the LMK458 suitable for use with marine fuel, which can have a storage temperature of up to 120degC?

The LMK458 has a media operating temperature range of -25 to +125 degC if specified with the TPE coated signal cable.

Minimum absolute and sealed gauge range

On the LMK458 marine approved submersible pressure sensor product data sheet it says that the sensor is “available in gauge, sealed gauge and absolute; nominal pressure ranges sealed gauge and absolute from 1 bar”. Does this mean the range is actually 1 to 11 bar absolute for example, and therefore they are just sealed gauge ranges with different markings, or do the available ranges start from 0 to 1 bar and upwards?

It means that the absolute and sealed gauge pressure ranges are only available from 0 to 1 bar and above.

Housing protection in seawater to depth of 70 metres

I need a deep sensor to measure down to 70 m depth in sea water for an offshore application. It will be attached to a metallic structure at the mentioned depth, and the metal structure will move , that’s why I need to know the depth.
The LMK 458 sensor seems to be suitable for use offshore and with sea water, but it is not clear to me about the housing, since the whole sensor and housing will be handling the pressure, we want to be sure that the housing will also support the sea water depth in all the variations, as a probe, screw, and flange connections?

Yes you can submerge the whole sensor to the required depth in seawater in any of the mounting configurations.  The electrical connection is sealed to IP68 and rated to at least 200 metres.

• SKU ID: s1-lmk458-0001
• Part No: 765-7001-K-1-2-1-1-4-2-100-000
• Pressure Range: 0 to 70
• Units: mH2O
• Reference Type: Gauge / Vented (atm to +P)
• Output Signal: 4 to 20 mA, 2 wire
• Accuracy: 0.25% FS
• Installation Type: Probe version with nose cone
• Housing Material: Copper Nickel Alloy (seawater compatible)
• Diaphragm Material: Ceramic Al2O3 96%
• Media Exposed Seals: FKM
• Cable Type: TPE (125degC max)
• Cable Length: 100
• Cable Length Units: Metres (m)

Towed underwater vehicles

I need a depth sensor for towing behind an offshore survey vessel to monitor depth of a towed underwater vehicles.  The range of depth will be 0-3 metres.

We would suggest the following LMK458 options:

• SKU ID: s1-lmk458-0002
• Pressure Range: 0-6
• Units: mH2O
• Reference Type: Gauge / Vented (atm to +P)
• Output Signal: 4 to 20 mA, 2 wire
• Accuracy: 0.25% FS
• Installation Type: Probe version with nose cone
• Housing Material: Copper Nickel Alloy (seawater compatible)
• Diaphragm Material: Ceramic Al2O3 96%
• Media Exposed Seals: FKM
• Cable Type: TPE (125degC max)
• Cable Length: 10
• Cable Length Units: Metres (m)

765-1600-1-1-2-1-3-4-2-008-000

What is the LMK458 specification for the part number 765-1600-1-1-2-1-3-4-2-008-000?

• SKU ID: s1-lmk458-0007
• Part No: 765-1600-1-1-2-1-3-4-2-008-000
• Pressure Range: 0.16
• Units: bar
• Reference Type: Gauge / Vented (atm to +P)
• Output Signal: 4 to 20 mA, 2 wire
• Accuracy: 0.25% FS
• Installation Type: Probe version with nose cone
• Housing Material: Stainless Steel 316L
• Diaphragm Material: Ceramic Al2O3 96%
• Media Exposed Seals: EPDM
• Cable Type: TPE (125degC max)
• Cable Length: 8
• Cable Length Units: Metres (m)

Related Documents

Specification data sheets

• LMK458 product data sheet
• LMK458H product data sheet
• LMK457 product data sheet [obsolete]

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