High Efficiency - Pilot valves

Solutions for high plant efficiency

Pilot operated safety valves

Highest blow-off capacity of all series
Tightness right up to set pressure
Operating pressures up to 96% of the set pressure
Back pressures up to 70% of the set pressure
Backflow preventer integrated as a standard component
Integrated Piping prevents damage and freezing

Supplementary Loading System

Equipment that enables the following safety valve characteristics:

Tightness right up to set pressure
Operating pressures up to 97% of the set pressure
Low loss of medium due to short opening times
Function test and valve adjustment possible during operation
Suitable for all media temperatures

Valve Types

Type 811

Pilot operated / Pop Action

DN 25 - DN 200 (1" - 8")

Type 821

Pilot operated / Modulate Action

DN 25 - DN 200 (1" - 8")

Type 702, 712, 714, 731

Supplementary Loading System (additional option for safety valves)

Technical data pilot operated safety valves

Nominal Diameter at Inlet: DN 25 - DN 200 | 1" - 8"
Actual Orifice Diameter d₀: 11 mm - 180 mm | 0.433 in - 7.087 in
Actual Orifice Area A₀: 95 mm² - 25,446.9 mm² | 0.147 in² - 39.443 in²
Pressure: 2.5 bar - 426 bar | 36 psig - 6170 psig
Temperature (in accordance with DIN EN): -48 °C to 200 °C | -54.4°F to 392°F
Body Material: 1.0619, 1.4408 | SA 352 LCB, SA 216 WCB, SA 351 CF8M
Valve Connection: Flange in accordance with DIN EN 1092, ASME B 16.5 or JIS 2220
Load Type: Medium controlled

Case Study

LESER LNG POSVs support high plant efficiency in liquefaction process

Industry/Application:

LNG / natural gas liquefaction plant

LESER Solution:

POSV, Compact Performance, API

Customer since:

For more than 20 years

Quantity of Valves Supplied:

288 safety valves: 6 Type 811, 47 Type 459 and 235 Type 526

The Challenge
The liquefaction process must be designed efficiently so that the LNG can be offered economically. The necessary cryogenic media temperatures of -161 to -164 °C represent a challenge for the technical design of the individual components in the plant. This also applies in particular to the safety valves, which must function reliably as the final protection in the event of overpressure, even at the cryogenic process and Russian ambient temperatures.
Linde expected its suppliers to provide a reliable and punctual delivery in addition to solving the technical requirements.

Why did the customer choose LESER products?
LESER valves meet all requirements for use in natural gas liquefaction plants and offer a complete product range. The valves are designed in the low-maintenance “Durable Design” and can be adapted to the plants by various options.

The tightness of the safety valves has been proven under real conditions at media temperatures below -146 °C on LESER’s own cryogenic test bench. The precise helium leak test is based on the DIN EN 13648-1 standard.

The plant efficiency was supported by the use of pilot-operated safety valves (POSV) in the relevant areas. In contrast to spring-loaded safety valves, they are tight until they respond and thus meet the requirement of a higher operating pressure in relation to the response pressure of the plant. Six POSVs now support the efficiency of LIMUM® technology the liquefaction plant.

The LESER POSV for LNG is based on the proven design for LPG applications - Liquefied Petroleum Gas, which has been in use for many years as a standardized solution.

For the LNG low temperature range, LESER has further developed the design modularly so that it can be adapted to the respective project requirements. In the plant in Russia, for example, an evaporator was used and the pilot was thermally decoupled from the main valve to ensure a gaseous media state in the pilot. A temperature-resistant PTFE compound for piston sealing in the main valve enables the spring-loaded lip seal to be used at operating temperatures as low as -162 °C. The main valve is equipped with a PTFE compound for the sealing of the piston. The special seat bushing design does not require a soft seal in the wetted inlet area. The controlling pilot valve is available with a low-temperature resistant soft seal in Pop Action and Modulate Action versions for various requirements.

LESER’s project department supported Linde from the first FEED phase to the commissioning of the project. The production segment “Project Assembly” is specially designed for the requirements of projects and offers optimal conditions for customer acceptance.

Why did the customer choose LESER products?
Linde relies on LESER’s know-how in the cryogenic market, for example in projects with temperatures down to -269 °C for liquid helium applications. The company has been working with LESER in the field of technical gases for many years and knows their services very well. The joint experience in the project management of air separation plants and the complete LNG product range, in particular the modular Cryo-POSV in the Pop Action version, were important for Linde.

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