Energy-Efficient Volume Flow Control
NEUMAN & ESSER already took the requirements for energy efficiency very seriously many years ago and therefore incorporated virtually loss-free volume control flow into its R&D plan. Without further ado, two development projects were registered simultaneously under the brand names of BLUEPOCKET® and BLUESTROKE® whereby a patent was also granted for the latter. Both work principles, whether via variable stroke setting or additional clearance pocket, provide output-adapted volume flow control of the reciprocating compressor and therefore a considerable contribution to increasing efficiency.
Whether in Europe, the USA or at globally active affiliated groups from the Petrochemicals and Oil & Gas sector – the demand of “Zero Emission” from machinery and systems is becoming more and more firmly anchored within the scope of sustainability and environmental protection for the operators. Accordingly, greenhouse gases such as CO2 and CH4 or toxic gases are no longer allowed to enter the atmosphere.
With diaphragm technology, which now comprises part of the NEA GROUP compressor portfolio as a result of the acquisition of Andreas Hofer Hochdrucktechnik, NEUMAN & ESSER is able to fulfill the postulate of absolutely emission- free compression. The construction principle of the diaphragm compressor, which is „hermetically sealed“, ensures this alone.
However, the design of the reciprocating compressor is different. In the crosshead version, leakage of the piston rod seal always occurs which, despite being minimal, can always escape into the atmosphere if the crankcase is not correspondingly sealed. Driven both by customer demands but also own R&D activities, e.g. for biogas feed compressors, the NEUMAN & ESSER Central Division of Technology (ZT) has already developed several of the proven crankcase sizes as gas-tight (GT) variants.
Whilst all moving parts in the crankcase have remained, special emphasis was placed on the stability of the cast material of the crankcase for the „GT“ version and on the selection of a suitable shaft seal for the crankshaft. In principle, dependent on the crankcase, the permissible tensions were either determined by “calculation” or by “compressing” and then deducing the necessary wall thicknesses.
Both methods resulted in the crankcase types now available with the supplement „GT“ for gas-tight (see illustration below from left to right: ZS25GT, EV1GT, EV63GT, ZS63GT, ZS80GT and ZS130GT). Depending on the application and the customer demands, the appropriate shaft seal is selected order-related. Here, gastightness and working life are the primary factors.
After some „lessons learned“, in particular in the biogas segment, a reliable solution now exists. Due to experience gained during the past five years as well as the selected design method for the crankcase, ZT can react very fast to sales’ requirements for further NEA crankcases for emission-free sealing – in concrete terms within two weeks. If technically feasible and desired by the customer, solutions with diaphragm technology and „Zero Emission“ will be looked for as a priority in the future, making gas-tight crankcase no longer necessary, but possible.