The autosamplers needle wash system enables to wash the inside and the outside of the needle to remove residual sample from the needle. The wash cycles can be part of the sampling sequence or can be performed manually.

The needle wash components are pre-installed within the autosampler upon shipment.

Outer needle wash

The needle wash system for the outside of the needle is supported by two needle wash pumps, which can deliver a strong or a weak needle wash liquid.

The outside of the needle can be washed automatically after drawing a sample or manually.

Inner needle wash

When performing the inner needle wash, the outside of the needle will be washed together with the inside of the needle. To ensure a low carry-over, also the needle seat and sample loop will be washed when performing the inner needle wash. Additional to the two needle wash pumps for the outer needle wash, the inner needle wash uses a weak needle wash liquid that flows through an online degasser located in the pump.

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Figure: Needle Wash Components

No.

Description

1

Wash line labeled with SWP (red) from strong wash reservoir to needle wash pump inlet, used for strong outer and inner needle wash.

Wash line labeled with WWP (green) from weak wash reservoir to needle wash pump inlet, used for weak outer needle wash.

2

Wash line labeled S (red) from strong wash reservoir to degasser inlet port in the pump, used for purging and short-term shutdown procedures.

Wash line labeled W (green) from weak wash reservoir to degasser inlet port at the pump, used for inner needle wash and purging.

3

Wash port

4

Wash lines from needle wash pump outlet to wash port

5

Needle wash pump

6

Wash lines from degasser outlet port at the pump to the autosampler.

7

Needle wash waste line