Copeland Stream 4M and 6M Semi-Hermetic Compressors

Overview

The Copeland Stream 4M and 6M ranges are semi-hermetic reciprocating compressors for commercial and industrial refrigeration. According to the Copeland application guidelines, the Stream series of 4M* and 6M* models covers displacements from 62 to 153 m³/h, from the 4-cylinder 4MF-13 up to the 6-cylinder 6MK-50, with nominal capacities from 13 to 50 hp. The compressors are used as single compressors, in condensing units or in multi-compressor racks, which makes them a core building block for supermarkets, cold stores, food factories and process cooling plants. They complement the CO2 versions of the Stream family, such as the 4MTL, which are designed for R744.

Seven Star LLC supplies the Copeland Stream 4M and 6M compressors and their accessories to refrigeration contractors, rack builders and end users in the Sultanate of Oman and across the GCC. Large hypermarkets in Muscat, central distribution centres, fish and meat processing plants in Duqm and Salalah, and dairy and beverage plants commonly run rack systems built on semi-hermetic compressors of this size. With engineering support in Muscat, our team helps match model, motor version, refrigerant and options such as capacity control and unloaded start to the existing plant.

Operating Principle

In general terms, a reciprocating compressor draws refrigerant vapour into its cylinders as the pistons move down and compresses it as they move up, with suction and discharge valves in a valve plate controlling the flow. In the Copeland Stream 4M and 6M, all models use a dedicated Copeland valve plate design, comparable to Discus valve plates, and the complete cylinder head area above the valve plate is under discharge pressure. The compressors are suction-gas cooled: incoming refrigerant passes over the motor before reaching the cylinders, and an additional cylinder head fan may be needed under some operating conditions.

Lubrication on the Copeland Stream 4M and 6M is provided by an external oil pump that works in the correct direction regardless of the direction of rotation, with normal oil pressure between 1 and 4.2 bar above crankcase pressure. Oil returns with the suction gas through a suction strainer and separates in the motor chamber, then reaches the crankcase through a relief valve that limits foaming at start-up. As with all Copeland compressors, a minimum stable suction superheat of at least 5 K is required for a typical evaporator and expansion valve configuration.

Engineering Design of the Copeland Stream 4M and 6M

On the Copeland Stream 4M and 6M, capacity can be matched to load in several ways. Mechanical capacity control uses the blocked suction principle, closing the suction port of a valve plate with a control piston: 50% on 4M* models, and 33% and 66% steps on 6M* models. Digital capacity control, identified by the letter D in the model code (4M*D or 6M*D), uses specially prepared cylinder heads and a fast-cycling solenoid valve to provide stepless modulation, from 50 to 100% on a 4M*D and from 33 to 100% on a 6M*D when combined with a blocked suction bank. An optional internal unloaded start system with a special cylinder head is available for part-winding or star-delta starting.

The Copeland Stream 4M and 6M compressors have been upgraded internally to support A2L refrigerants; models marked with revision number 2 in the nomenclature, from serial number 21J7611M (October 2021) onwards, are approved for R454C, R455A and R454A as well as A1 refrigerants. Maximum allowable pressure PS is 32.5 bar(g) on the high-pressure side and 22.5 bar(g) on the low-pressure side. Liquid injection, using the Copeland Compressor Electronics module with extension module C or the traditional Demand Cooling concept, may be required for some low temperature duties with R448A and R449A. Compressors with Copeland Compressor Electronics include integrated oil pressure safety functionality.

Key Features

The Copeland application guidelines describe these key features of the Copeland Stream 4M and 6M range.

• Sixteen models from 4MF-13 to 6MK-50 cover 62 to 153 m³/h displacement and 13 to 50 hp nominal capacity.
• Qualified A1 refrigerants include R448A, R449A, R407A, R407F, R404A, R407C, R513A, R450A, R134a and R22.
• Revision 2 compressors are also approved for the A2L refrigerants R454C, R455A and R454A.
• Every Copeland Stream 4M and 6M model uses dedicated Copeland valve plates, which support high capacity.
• Mechanical blocked suction capacity control and stepless digital capacity control are available.
• An optional internal unloaded start supports part-winding and star-delta motor starting.
• The external oil pump works in either direction of rotation, and electronics versions monitor oil pressure.
• Liquid injection options keep discharge temperatures within limits in low temperature applications.

Industrial Applications

Typical applications of the Copeland Stream 4M and 6M include supermarket and hypermarket rack systems, central cold stores and logistics hubs, blast freezers and frozen food storage, fish, meat and poultry processing, ice production, dairy plants, beverage and brewing cooling, and industrial process chillers using DX refrigeration. Table data in the guidelines, for example 76.4 kW for the 6MK-50 with R448A or R449A at –10 °C evaporating and 45 °C condensing, show the capacity range these compressors bring to medium temperature systems.

Seven Star LLC supplies the Copeland Stream 4M and 6M together with other Copeland compressors such as the DWM Copeland D8SJ1-600X semi-hermetic compressor, the Copeland D3DS5-1500-AWM/D semi-hermetic compressor and the Copeland ZR125KCE scroll compressor. Our team in Muscat supports contractors across Oman and the GCC with replacement selection, accessories and documentation.

Technical Specifications

The table lists Copeland Stream 4M and 6M data from the Copeland application guidelines (Table 1 conditions: evaporating –10 °C, condensing 45 °C, suction gas 20 °C, subcooling 0 K).

How to Order

To order a Copeland Stream 4M or 6M compressor, send Seven Star LLC the full model, motor version and serial number from the nameplate, or the refrigerant, required capacity and operating conditions. Our refrigeration team in Muscat will confirm the selection, share the technical documentation for download and prepare a formal quotation. Seven Star LLC supplies Copeland compressors to customers in Oman and the GCC with engineering support.