RKI Instruments 30-0954RK-250 Series Operator's Manual

30-0954RK-250 Series Sample Draw
Aspirator Adapter
Operator’s Manual
Part Number: 71-0218RK
Revision: P1
Released: 11/3/10
www.rkiinstruments.com
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2 • 30-0954RK-250 Series Sample Draw Aspirator Adapter
Overview
This manual describes the 30-0954RK-250 Series sample draw aspirator adapter. It also describes
how to install and use the adapter. A spare parts list at the end of this manual lists replacement
parts.
Specifications
Table 1 lists specifications for the Sample Draw Aspirator Adapter.
Table 1: Specifications
Applicable Detector Heads
65-3050RK Detector/Transmitter
Maximum Compressed Air Supply Pressure
140 PSI
Outlet Pressure to Aspirator
5 - 50 PSI adjustable (determined by required flow rate)
Recommended Sample Flow Rate
3 SCFH (standard cubic feet per hour)
Description
The sample draw aspirator adapter uses compressed air flowing through a venturi to draw air into a
sample chamber.
Detector
Head 2
(optional)
Restrictor
Calibration Gas
Fitting
Flow Meter
Detector
Head 1
Flow
Fail
Switch
Inlet/Blowback
Valve
Calibration
Valve
Sample
Filter
Compressed
Air In
Regulator
Aspirator
Exhaust
Restrictor
Figure 1: Flow Diagram
30-0954RK-250 Series Sample Draw Aspirator Adapter • 3
Flow Meter
Detector
Head with
Flow-Through
Adapter
2
Detector
Head with
Flow-Through
Adapter
1
OUT
(optional)
IN
OUT
IN
Calibration
Valve
Pressure Adjustment
Knob
Pressure
Gauge
Calibration Valve
Push Button
Pressure Regulator
Calibration Fitting
Aspirator
Low Flow
Switch
Aspirator/Sample
Exhaust (1/8 NPT female)
-
+
Inlet/Blowback
Valve
Low Flow Housing
Inlet/Blowback Valve Button
1/4 O.D. Tube Compressed Air
Inlet Fitting
Water Trap
1/4 O.D. Tube Sample Inlet Fitting
Figure 2: Component Location
The sample draw adapter consists of nine major components (see Figure 2 ): the detector head (1 or
2), regulator, aspirator, flow-through sample adapter (1 or 2), flowmeter, calibration valve, inlet/
blowback valve, low flow switch, and low flow contact housing.
Detector Head(s)
Each detector head provides a signal that can be used by a controller to indicate the sample gas
level. The 65-3050RK detector/transmitter is used with the 30-0954RK-250 sample drawing
adapter plate. Figure 2 above shows the approximate location of the two detector heads. Please see
the detector head operator’s manual of the detector head(s) in your system for a complete
description of the detector head(s).
4 • 30-0954RK-250 Series Sample Draw Aspirator Adapter
Regulator
The regulator has an inlet port on its left side with a 1/4” tube fitting. The maximum allowable inlet
pressure is 140 PSI. A gauge at the bottom of the regulator indicates the output pressure. The output
pressure, and detector flow, can be adjusted using the knob on the front of the regulator. The
detector flow rises or falls as the output pressure is increased or decreased.
Aspirator
The aspirator inlet is connected to the output port on the right side of the regulator and the vacuum
port on top is connected to the detector chamber. It has a venturi tube inside it which generates a
vacuum at its top port when compressed air flows through it. The compressed air and the air drawn
from the flow-through sample adapter into the top port of the aspirator both exhaust at the right side
of the aspirator.
Flow-Through Sample Adapter
The flow-through sample adapter is screwed into the detector adapter. The inlet of the flow-through
sample adapter is on the bottom and is connected to one of the flowmeter’s exhausts. The exhaust
of the flow-through sample adapter is at the side and is connected to the vacuum port of the
aspirator.
Flowmeter
The flowmeter indicates the flow to the detector(s). It has a 1/4” OD tube fitting at its inlet and
exhaust port. The exhaust port splits into two sections in order to control the flow to the detector.
One section has a restrictor and goes directly to the exhaust port. The other section goes to the
detector chamber or to the first detector chamber if two detector heads are installed. The
flowmeter’s indication range is 1 - 10 SCFH. It has no flow adjustment valve because the flowrate
is controlled by the regulator setting.
Calibration Valve
The calibration valve is a manual operation spring return valve with a push button actuator. This
valve is used to switch from sample flow to calibration gas during the calibration process. When
the button is pushed and held, the sample port is closed and the calibration port is opened.
Inlet/Blowback Valve
The inlet/blowback valve is a manual operation spring return valve. A push button actuator is
located on the front of the valve. This valve is used to switch from sample flow to blow back in the
event of a clogged sample line. When the push button is pressed and held, the valve diverts the
compressed air supply back through the sample line to clear obstructions.
WARNING:
The blowback pressure can be as high as 140 PSI. Make sure that all personnel
and equipment are clear of the sample line inlet end to avoid personal injury or
equipment damage if a sample line obstruction is blown out of the sample line.
Low Flow Switch/Low Flow Contact Housing
The low flow switch provides a normally open contact that closes in the event of a low flow
condition. Two contact wires protrude from the side of the switch and enter the low flow contact
housing through a plastic cable bushing on the left side of the housing. Terminals are provided in
the housing for field connection to the switch contacts. A second plastic cable bushing on the
bottom of the low flow contact housing allows for cable entry to the housing. The size range of the
cable which can be routed through the second cable bushing is .064’’ - .210’’ OD.
30-0954RK-250 Series Sample Draw Aspirator Adapter • 5
Installation
(4X) Ø 0.50
19.25
0.75
Detector
Head with
Flow-Through
Adapter
Detector
Head with
Flow-Through
Adapter
1
2
(optional)
OUT
IN
OUT
IN
Low Flow Contact Housing
19.25
20.75
Aspirator/Sample Exhaust
-
+
Field Wiring Cable
Entry Bushing for
Switch Contact
0.75
140 PSI Compressed
Air Inlet
Sample Inlet
20.75
Figure 3: Outline & Mounting Dimensions
1.
Install the mounting panel to a flat horizontal surface using the four mounting holes (0.50’’
diameter) in the corners of the panel. Make sure that sufficient space is allowed to remove the
detector head’s cover, and to bring power/signal wiring to the detector head. Also provide
sufficient clearance for routing of sample, compressed air, and exhaust lines.
2.
Connect power/signal wiring to the detector head(s) as described in the detector head
operator’s manual.
3.
Start up the detector head(s) as described in the detector head operator’s manual.
4.
Connect a sample line from the area to be sampled to the sample inlet fitting at the bottom right
of the panel. The fitting accepts 1/4” OD rigid metal tubing such as copper, aluminum, or
stainless steel tubing. Be sure to use tubing appropriate for the target gas.
5.
The aspirator exhaust includes the sample air. It may be routed to a different area where it can
6 • 30-0954RK-250 Series Sample Draw Aspirator Adapter
be exhausted safely by running tubing from the aspirator exhaust fitting to the “safe” area. The
aspirator exhaust fitting is a 1/4’’ OD tubing fitting.
6.
Turn the regulator adjustment knob completely counterclockwise and then turn it one turn
clockwise so that the flow will start out at a low level when the compressed air is connected
and turned on.
7.
Connect a compressed air source up to a maximum of 140 PSI to the inlet of the regulator.
Although the regulator is rated up to 300 PSI inlet pressure, other components are rated to a
maximum of 140 PSI.
8.
Adjust the regulator adjustment knob so that the flowmeter indicates 3 SCFH. The regulator
exhaust pressure indicated by the regulator gauge will vary for a particular flow depending on
the length of the sample line and other restrictions such as filters. Typically the pressure will be
between 5 and 10 PSI for short sample runs. It will be higher for longer sample runs and if
filters are used.
NOTE: The 30-0954RK-250 includes a sample bypass which routes much of the sample flow
around the detector(s). This maintains an optimal flowrate to the detector(s) of
approximately 1 SCFH while minimizing the response time with a 3 SCFH sample
flowrate.
9.
Calibrate the detector head(s) as described below.
Calibration
1.
Follow the instructions in the detector head operator’s manual for setting the zero (fresh air)
reading and making span adjustments.
2.
When introducing gas to the detector, fill a gas sample bag with a regulator or dispensing
valve. See “Parts List” on page 8 for available parts.
NOTE:
A gas bag is recommended for calibration instead of a demand flow regulator because a
demand flow regulator introduces enough flow restriction to significantly reduce the
flow. If a demand flow regulator is used, the flow will have to be adjusted up to 3 SCFH
while the regulator is connected during calibration and down to 3 SCFH after calibration.
3.
Connect the sample bag tubing to the hose barb calibration fitting on the calibration valve.
4.
Push and hold the button on the calibration valve to start the flow of gas through the calibration
gas fitting. Allow the sample draw adapter to draw sample for 2 minutes and then make any
calibration adjustments necessary.
5.
Release the push button on the calibration valve. Disconnect the sample bag from the
calibration fitting.
Blowback Operation
1.
In the event of a clogged sample line, the blowback valve can be used to divert the compressed
air supply back through the sample line to clear obstructions.
2.
Inspect the sample line first to try to remedy the situation without using the blowback valve. If
the line cannot be cleared, operate the blowback valve as described below.
3.
Make sure that all personnel and equipment are clear of the inlet end of the sample line.
30-0954RK-250 Series Sample Draw Aspirator Adapter • 7
4.
To operate the blowback valve, press and hold the button on the front of the blowback valve.
As long as the button is held, compressed air will be applied to the sample line.
WARNING:
5.
The blowback pressure can be as high as 140 PSI. Make sure that all personnel
and equipment are clear of the sample line inlet end to avoid personal injury or
equipment damage if a sample line obstruction is blown out of the sample line.
Release the button on the blowback valve. Verify that the sample is now flowing properly
through the sample line.
Parts List
Table 2 lists replacement parts and accessories for the sample draw adapter.
Table 2: Parts List
Part Number
Description
06-1248RK-03
Tubing, 3/16 x 5/16, polyurethane, 3 foot length, for calibration kit
35-2000RK
Flow-through sample adapter
81-1001RK
Dispensing valve, for 34 liter steel cylinders
81-1051RK-60
Regulator with gauge and knob, 6 LPM, for 34 liter aluminum cylinder,
58 liter aluminum or steel, and 103 liter aluminum or steel cylinder
81-1127RK
Gas bag with fittings and hosebarb, 12 inches x 12 inches, 5 liters, tedlar
8 • 30-0954RK-250 Series Sample Draw Aspirator Adapter