RKI Instruments 35-3000RKA-10 - Manual (Page 6)

6 • 35-3000RK-10 PPM Hexane Sample Draw Detector
Flow System
The sample draw detector’s flow system consists of the inlet fitting, exhaust fitting, pump,
flowmeter, bypass valve, flow block, status LEDs, and pressure switch (see Figure 1).
Figure 2 below illustrates how the gas sample moves through the flow system.
Figure 2: Flow Diagram
Inlet Fitting
The inlet fitting on the right side of the housing allows the gas sample to enter the sample-
draw detector. The inlet fitting accepts 1/4 in. rigid tubing. See “Connecting the Sample
Lines to the Sample Draw Detector” on page 11 to connect tubing to the inlet fitting.
Exhaust Fitting
The exhaust fitting on the right side of the housing allows the gas sample to exit the
sample draw detector. The exhaust fitting accepts 1/4 in. rigid tubing. See the
“Connecting the Sample Lines to the Sample Draw Detector” on page 11 to connect tubing
to the exhaust fitting.
Hydrophobic Filter
The hydrophobic filter is behind the main circuit board near the bottom edge of the board.
The filter prevents particulates and water in the incoming gas sample from damaging the
flow and detection systems. Replace the filter when it appears dirty, discolored, or
clogged.
Pump
The pump is behind the main circuit board near the top of the sample-draw detector.
The pump pulls the gas sample into the sample-draw detector. The pump operates on
24 VAC, which is generated from the 24 VDC supplied to the sample draw detector.
Flowmeter
The flowmeter is attached to the main circuit board near the top left corner (see Figure 1.)
You can see it through the window in the door. A ball in the flowmeter column indicates
the flow rate of the sample draw detector. The flowmeter measures the flow in the range
0.2 to 2.0 SCFH (Standard Cubic Feet per Hour). The optimum flow rate is 1.5 SCFH.
Exhaust
Bypass
Valve
Presure Switch
Detector
Flowmeter
Pump
Inlet
Hydrophobic
Filter