Heavy Duty Balanced Opposed Compressors - Ariel Corporation
Heavy Duty Balanced Opposed Compressors - Ariel Corporation
Heavy Duty Balanced Opposed Compressors - Ariel Corporation
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FOR MODELS: JGZ AND JGU SECTION 4 LUBRICATION<br />
In limited circumstances and with prior approval from <strong>Ariel</strong>, cold weather installations may use<br />
multi-viscosity oils in the compressor frame if the oil supplier can certify that the oil is shear stable.<br />
The viscosity of shear stable oil degrades less through use. Most oil suppliers will certify<br />
their oil as shear stable if the viscosity degrades less than a certain percentage in specific tests.<br />
As a result, multi-viscosity oils are subject to a shorter oil life than single straight grade oils by<br />
30% to 50%.<br />
Synthetics such as PAG, PAO, or ester based lubricants are acceptable in the compressor<br />
frame provided they meet the operating viscosity requirements as outlined below.<br />
Compounded lubricants are prohibited in the frame.<br />
Oil Viscosity<br />
The minimum allowable viscosity of the oil going into the frame is 82.6 SUS (16 cSt). Typically<br />
this is the viscosity of ISO 150 grade oil at about 190°F (88°C).<br />
The maximum viscosity of the lube oil for cold ambient temperature starting is 15,000 SUS<br />
(3300 cSt). Typically this is the viscosity of ISO 150 grade oil at about 25°F (-4°C).<br />
Oil Pressure<br />
Normal pressure on the discharge side of the lube oil filter is factory set for 60 psig (4.1 bar g )<br />
for compressors that were tested mechanically complete (has inspector tag). If tested at factory<br />
as mechanically incomplete (without inspector tag), normal oil pressure must be set by packager<br />
or at initial start-up to 60 psig (4.1 bar g ) at the lower of the Frame Rated Speed, cylinder<br />
(RPM) or driver speed, and at normal operating temperature. If the lube oil pressure drops below<br />
50 psig (3.4 bar g ), the cause should be found and corrected. A low lube oil pressure shutdown,<br />
set at 35 psig (2.4 bar g ), is required for protection of the compressor during a sudden<br />
loss of oil pressure. The compressor should not operate for prolonged periods of time at less<br />
than 50 psig (3.4 bar g ) oil pressure.<br />
For proper operation of the thermostatic control valve, the maximum differential pressure between<br />
the hot oil supply line and the cooled oil return line is 10 psid (0.7 bar d ).<br />
Oil Temperature<br />
The minimum lube oil operating temperature is 150°F (66°C). This is the minimum temperature<br />
required to drive off water vapor.<br />
Maximum allowable oil temperature into the compressor frame is 190°F (88°C).<br />
A thermostatic control valve supplied by <strong>Ariel</strong> is set at 170°F (77°C). The oil temperature should<br />
be maintained as close to this temperature as possible. Higher temperatures increase the oxidation<br />
rate of the oil. For every 18°F (10°C) over 150°F (66°C), the oxidation rate of the oil doubles.<br />
Oil Maintenance<br />
Compressor frame lubricating oil should be changed as indicated in the regular maintenance<br />
intervals or with a filter change or when oil analysis results indicate the need. A more frequent<br />
oil change interval may be required if operating in an extremely dirty environment without sampling<br />
and analysis or if the oil supplier recommends it.<br />
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