Leobersdorfer Maschinenfabrik now offers pressure-proof boxer compressors specifically tailored to the requirements of grid-connected biogas facilities. LMF can proudly look back at 25 years of experience in the manufacturing of high-pressure equipment, and combines this know-how with the technology of high-speed boxer compressors.

During operation of a piston compressor, a small amount of process gas escapes from the compression chamber of the cylinder through the piston rod seal. The amount of this blow-by gas depends on the wear status of the piston rod seal, i.e. on the number of operating hours of the compressor. In a conventional design, this blow-by gas is discharged into the atmosphere through a leakage line in the roof, or is burned through a flare system. This loss of process gas needs to be minimized for both economic and environmental reasons. By using compressors in a "pressure-proof" or "flameproof encapsulated“ design, the amount of blow-by gas is reduced to zero, rendering such compressors emission-free. The LMF BS302D design series fully meets these emission-free requirements.


The advantages of BS 302D:
• Conformity with the German DVGW regulations (496 / 497 and VP 265-1)
• Pressure-proof up to 20 bar
• High-speed boxer engine (up to 1250 rpm)
• Water-cooled cylinders
• Dry-running cylinders
• Balanced-opposed designed for reduced load on the foundation

Functions:
The BS302D compressor unit consists of a crank-gear, roughly composed of the casing, the crankshaft, the crosshead, the connecting rod, the piston rod and the counterweights; in addition, the crankcase also serves as a reservoir for the oil of the engine lubrication system.
The crosshead guides are mounted directly onto the crankcase, containing the crossheads and an oil scraper as a retainer for the engine lubricating oil. Depending on the design, the next immediate component is either the cylinder, in which the process gas is compressed, or, as in the case of dry-running biogas applications, an intermediate piece that keeps the crankcase lube oil away from the compression chamber.
In the case of the pressure-proof BS302 design, the process gas escaping from the compression chamber through the piston rod seal during operation is not discharged into the atmosphere but is retained in the machine. A line connecting the crankcase with the compressor’s suction line ensures that the pressure inside the compressor does not rise above that of the suction line. As a standard, the pressure-bearing parts of the compressor, i.e., the crankcase, the crosshead guides, and the intermediate pieces are designed for an operating pressure of 20 bar, which can be raised to 25 bar for special applications. The assembly and maintenance covers on the outer side are sealed using commercial flat gaskets or O-rings, while the crankshaft is sealed using a double-acting mechanical seal. The mechanical seal is a cartridge design, i.e., the sealing elements are correctly and exactly adjusted in the customer’s workshop, either by LMF or by the manufacturer of the seal, and then built into the compressor as a preassembled package. The mechanical seal features a sealing medium that actually guarantees zero leakage; in addition, process gas does not escape into the atmosphere even if the seal is defect. The sealing medium is monitored by a differential pressure sensor on the seal, which can optionally trigger an alarm if desired. Since the sealing medium is inserted into the seal using a pump with a separate electric drive, the entire compressor system is 100% leakage-free even when idling.