Background Image
Previous Page  41 / 124 Next Page
Information
Show Menu
Previous Page 41 / 124 Next Page
Page Background

COMPRESSOR PROTECTIVE DEVICES

High Pressure Oil Management System

High Pressure Oil Management Systems remove the need for a separate Oil

Reservoir. This type of system also reduces the amount of pipework and

fittings.

A High Pressure Oil Management System relies on the Oil Level Regulators

being able to operate with a high pressure differential. Mechanical Oil Level

Regulators cannot be used on this type of system. The Electronic Oil Level

Regulator (14) is recommended for this application. Electro-Mechanical

Regulators can also be used. A High Pressure Oil Management System is

not recommended for HCFC/mineral oil systems due to potential foaming

problems.

The common discharge is piped to the inlet of the Oil Separator-Reservoir

(13) and the outlet of the Separator-Reservoir is piped to the condenser.

The oil return connection, positioned at the bottom of the vessel,

is piped to the Oil Level Regulators. An Oil Filter (10) or Oil Filter-Drier (11)

should be installed between the Oil Separator-Reservoir and the Electronic

Oil Level Regulators (14).

It is recognized best practice to fit a solenoid valve, sight glass, and

shut-off valve in the oil return line. These components are not shown in the

diagram.

A

Discharge Check Valve (4) should be fitted between the Separator and

Condenser to ensure condensed liquid refrigerant is not returned to the

Separator.

1.

Compressor.

2.

Oil Separator

The function of an Oil Separator is to remove oil from

the discharge gas and return it to the compressor, either directly or

indirectly. This helps maintain the compressor crankcase oil level and

raises the efficiency of the system by preventing excessive oil circulation.

Oil Separators are not 100% efficient, so installing an Oil Separator

should not be viewed as a replacement for oil traps, accumulators, or

good oil return piping practices. Henry Technologies’ manufactures two

different types of Oil Separators, Helical and Conventional.

3.

Condenser.

4.

Discharge Check Valve

The function of a Check Valve is to allow

fluid flow in one direction only. This prevents condensed liquid refrigerant

returning down the discharge line into the Separator. If this Check Valve

is not installed the Separator can feed excessive liquid refrigerant to the

Compressor on start up. This can cause oil dilution, excessive foaming,

erratic oil pressures and possible compressor damage. The Check Valve

must be installed after the Oil Separator, before the Condenser.

5.

Oil Strainer

The function of an Oil Strainer is to remove system debris

from the refrigerant oil. Their purpose is to protect compressors and Oil

Level Regulators from damage. For recommendations on HFC/POE

systems, refer to section on oil filters and oil filter-driers.

6.

Oil Return Line.

7.

Oil Reservoir

The function of an Oil Reservoir is to provide a holding

charge of oil, as part of a Low Pressure Oil Management System. The

amount of oil circulating in a system varies depending on the operating

conditions. The Oil Reservoir caters to these fluctuations by providing

additional storage capacity.

8.

Vent Line.

9.

Mechanical Oil Level Regulators

The function of a Mechanical Oil

Level Regulator is to control the oil level in the compressor crankcase.

This protects the compressors from damage. There are two main types

of Oil Level Regulators, fixed level and adjustable level. The fixed level

regulators have an allowable oil pressure differential range of 5 to 30 PSI

(0.35 to 2.1 Bar). The adjustable level regulators have an allowable oil

pressure differential range of 5 to 90 PSI (0.35 to 6.2 Bar). Oil pressure

differential is the difference between the crankcase pressure and the

pressure in the Oil Reservoir. Gravity pressure head should be included

also, if applicable. Some regulator models are fitted with an equalization

connection that enables the oil levels between several compressors to

be balanced.

10.

Oil Filter

The function of an Oil Filter is to remove system debris

from the refrigerant oil. An Oil Filter is recommended for HFC/POE

systems instead of individual Oil Strainers, where filtration only is

required.

11.

Oil Filter-Drier

The function of an Oil Filter-Drier is to remove both

system debris and moisture from the refrigerant oil. An Oil Filter-Drier is

recommended for HFC/POE systems instead of individual Oil Strainers,

where both filtration and moisture removal is required.

12.

Reservoir Pressure Valve

The function of a Reservoir Pressure

Valve is to maintain a positive pressure in the Oil Reservoir above the

compressor crankcase pressure. Two different pressure settings are

available; 5 psi (0.34 Bar) and 20 psi (1.38 Bar). A higher pressure

differential will increase the oil flow rate from the oil reservoir back to the

compressors. The pressure setting should be selected taking into

account the allowable oil pressure differential of the Oil Level Regulator

type.

13.

Oil Separator-Reservoir

The function of an Oil Separator-Reservoir

is to provide a Oil Separator and Oil Reservoir in one unit. It is designed

for High Pressure Oil Management Systems and used with Electro-

Mechanical or Electronic Regulators.

14.

Electronic Oil Level Regulator

The function of the Electronic Oil

Level Regulator is to control the oil level in the Compressor crankcase.

This protects the Compressors from damage. This regulator can be used

on Low or High Pressure Oil Management Systems.

Refer to equipment list for further details on each

component in the oil system

HIGH PRESSURE OIL MANAGEMENT SYSTEM

EQUIPMENT LIST FOR OIL LEVEL CONTROL

4

13

10, 11

6

14

1

1

1

1

41