Delta-P II and INT250 oil differential pressure switches

Reciprocating compressors are usually equipped with oil pumps to ensure reliable oil lubrication. To guarantee that a sufficient quantity of oil is transported and to prevent damage to the compressor, these compressor types are usually equipped with oil differential pressure switches. If an insufficient oil quantity is detected, the compressor is shut down by the safety chain after a certain period of time.

Precise, reliable measurements prevent errors and increase the service life of the system. The special feature of the KRIWAN products for oil differential pressure measurement is the high flexibility due to the unique two-component system, as well as the compatibility when integrated into existing systems.

Oil differential pressure switches as stand-alone solution or for integration into your systems

Easy connection to your systems

KRIWAN differential pressure sensors can be distinguished into two types: Delta-P II and INT250.

Thanks to a potential-free relay, the Delta-P II monitors the oil differential pressure independently and reliably without the need for an additional monitoring and control system. It can be integrated directly into the safety chain.

In contrast, the INT250 can be connected directly to your PLC or a KRIWAN INT69 TML. For example, remote access is possible with some systems. Depending on the system, the installation effort is greatly reduced.

Product family

KRIWAN has developed a product family of evaluation units and screw-in parts that are characterized by their reliable oil differential pressure monitoring and simple handling. Thus, no additional external capillary tubes are required. The unique two-part design of evaluation unit and screw-in part allows the switch to be replaced without the need for time-consuming evacuation of the refrigeration circuit and draining of the oil.

Advantages KRIWAN oil differential pressure switches

Operating principle oil differential pressure switches

The KRIWAN solution for oil differential pressure monitoring consists of evaluation electronics and a screw-in unit that can be mounted and replaced separately. The screw-in part is installed directly in the pump. It measures the pump and suction pressure through internal channels and calculates the difference.

Oil pressure ok

Oil pressure ok

Oil pressure ok

At high pump pressure, the piston in the screw-in part is pressed forward and thus moves away from the evaluation unit. The electronics detect this distance, measuring that there is sufficient oil differential pressure.

Oil pressure low

Oil pressure low

Oil pressure low

If the pump pressure is too low, the oil differential pressure is not sufficient to move the cylinder. In this case, the sensor immediately reports this to the downstream electronics (on the INT250) or interprets the signal independently (on the Delta-P II), and switches off the compressor after a defined delay time via the safety chain as a precaution.

Screw-in parts for oil differential pressure switches Delta-P and INT250

In addition to the evaluation unit, the two-component system also includes the matching screw-in part. Our screw-in parts for the differential pressure switches are available for two different thread types, 3/4" -16UNF-2A or M20x1.5.

 

Thread 3/4"-16UNF-2A

Article number Operating pressure Differential pressure     Medium temperature
02D442S021 140 bar 0,65 bar -30°C...+90°C
02D443S020 140 bar 0,95 bar -30°C...+90°C

02D444

60 bar 0,95 bar -30°C...+90°C
02D446 140 bar 0,65 bar -30°C...+90°C

 

Thread M20x1,5

Article number Operating pressure Differential pressure     Medium temperature
02D555 60 bar 0,65 bar -30°C...+90°C
02D556 60 bar 0,95 bar -30°C...+90°C
02D557 140 bar 0,65 bar -30°C...+90°C
02D557S21 140 bar 0,65 bar -30°C...+90°C
02D558 140 bar 0,95 bar -30°C...+90°C

Information on the Delta-P II and INT250 oil differential pressure switches

What possibilities do the KRIWAN Delta-P II and INT250 oil differential pressure switches offer in practice? Our application sheet gives you interesting insights.

Application Sheet

Semi-hermetic reciprocating refrigerant compressors

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Brochure

HVAC/R protection solutions

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FAQ to the oil differential pressure switches Delta-P and INT250

What is the difference between the Delta-P II and INT250?

With the Delta-P II, the oil differential pressure is monitored independently and reliably without the need for an additional monitoring and control system. It can be directly integrated into the safety chain as it has a potential-free relay. Unlike the Delta-P II, the INT250 can be connected directly to your PLC or a KRIWAN INT69 TML. For example, remote access is possible with some systems. Depending on the system, the installation effort is greatly reduced.

Can I adjust the differential pressure?

No, the differential pressure was specified together with the compressor manufacturers. Depending on the compressor type, the differential pressure specified by design is 0.65bar or 0.95bar.

Which differential pressure is measured?

Some types of compressors use an oil pump to lubricate the system. The difference between the low- and high-pressure side of the pump is measured. If the differential pressure is present, the pump will operate properly. If the differential pressure is not present, the oil pump is malfunctioning and there is a risk of damage to the compressor.

Can I use a differential pressure sensor together with an optical screw-in part of a KRIWAN level switch?

No, the screw-in parts differ due to different measuring principles. The differential pressure is determined by means of a magnet and Hall sensor, the optical screw-in parts of the level switches determine the level by the different refraction of the light.

You have further questions? Our experts will be pleased to advise you!

 

Kevin Baumann

Vertriebsingenieur

+49 (0) 79 47 - 8 22 - 0
sales@kriwan.de

Felix Herrlein

Key Account Manager

+49 (0) 79 47 - 8 22 - 0
sales@kriwan.de