Instructions and
Operating Manual
SERIES X90
POINT LEVEL MONITORS
POINT LEVEL MONITORS
SERIES X90
Instructions and Operating Manual
Customer’s Name ____________________
Customer’s P.O. No.
__________________
Ronan Job No. ______________________
TABLE OF CONTENTS |
|
|
1.0 |
General Description ......................................................................................................... |
2 |
2.0 |
Specifications (Standard) ................................................................................................. |
2 |
3.0 |
Theory of Operation ......................................................................................................... |
3 |
4.0 |
Functional Options ........................................................................................................... |
3 |
4.1 |
High-Limit Process Alarm ................................................................................................ |
3 |
4.2 |
Low-Limit Process Alarm ................................................................................................. |
3 |
4.3 |
Failure Alarm ................................................................................................................... |
3 |
5.0 |
Time Delay Options ......................................................................................................... |
4 |
5.1 |
Relay Contacts ................................................................................................................ |
4 |
6.0 |
Circuit Description ........................................................................................................... |
4 |
7.0 |
Installation and Electrical Connection—General ............................................................... |
4 |
7.1 |
Remote Probe X90-1004 .................................................................................................. |
4 |
7.2 |
Model X90GPE ................................................................................................................ |
4 |
7.3 |
Integral Model X90-1005 .................................................................................................. |
5 |
8.0 |
Calibration Controls ......................................................................................................... |
5 |
9.0 |
Calibration—General ....................................................................................................... |
5 |
9.1 |
Calibration with Process Material ..................................................................................... |
5 |
9.2 |
Calibration without Process Material ................................................................................ |
5 |
9.3 |
Time Delay ...................................................................................................................... |
5 |
9.4 |
Response Time ............................................................................................................... |
5 |
10.0 |
Troubleshooting ............................................................................................................... |
6 |
11.0 |
Radiation Safety .............................................................................................................. |
6 |
11.1 |
Field Intensity Calculation ................................................................................................ |
7 |
11.2 |
NRC Regulations ............................................................................................................. |
9 |
11.3 |
Periodic Leakage Test ..................................................................................................... |
10 |
11.4 |
Radiation Publications ..................................................................................................... |
10 |
11.5 |
Abandonment and Disposal ............................................................................................. |
10 |
11.6 |
Prohibition of Operation ................................................................................................... |
10 |
11.7 |
Mounting and Start-up ..................................................................................................... |
10 |
11.8 |
Well Source Holders SA-4, SA-10, SA-15 ........................................................................ |
11 |
11.9 |
Standard Sources SA-1, SA-8 .......................................................................................... |
12 |
11.10 |
Mandatory Reporting ....................................................................................................... |
12 |
12.0 |
Leak Test Procedures for Sealed Sources ........................................................................ |
13 |
12.1 |
Ronan Leak Testing Service ............................................................................................ |
13 |
12.2 |
Using the Leak Test Kit .................................................................................................... |
13 |
13.0 |
Parts Lists |
|
|
X90-1004 or X90-1004X Probe ......................................................................................... |
13 |
|
X90-301(V) ...................................................................................................................... |
14 |
|
X90-1005 ......................................................................................................................... |
16 |
14.0 |
Drawings and Schematics |
|
|
Schematic—X90-1005 Point Level Monitor ...................................................................... |
19 |
|
Schematic—X90-301(V) Relay Circuit ............................................................................. |
20 |
|
Schematic—X90-301(V) Component Layout .................................................................... |
21 |
|
Schematic—X90-1004 Driver Board ................................................................................ |
22 |
|
Outline Drawing—X90-1004 Component Layout Driver Board .......................................... |
22 |
|
Outline Drawing—X90-SM/X90-301(V) Interconnect Wiring ............................................. |
23 |
|
Outline Drawing—X90 Remote G-M Tube Wiring ............................................................. |
24 |
|
Schematic—X90-301(V) Terminal Arrangement .............................................................. |
25 |
|
Outline Drawing—X90 Explosion-Proof Housing .............................................................. |
26 |
|
Outline Drawing—Single-Point Chassis Model X90GPE ................................................... |
27 |
|
Outline Drawing—X90 Remote Tube Housing .................................................................. |
28 |
|
Outline Drawing—Front and Rear Panels, X90 Gamma Switch ........................................ |
29 |
|
Outline Drawing—NEMA Type 4 Enclosure ...................................................................... |
30 |
Warranty Ronan warrants equipment of its own manufacture to be free from defects in material and workmanship under normal conditions of use and service, and will repair or replace any component found to be defective, on its return, transportation charges prepaid, within one year of its original purchase. this warranty carries no liability, either expressed or implied, beyond our obligation to replace the unit which carries the warranty.
1.0 GENERAL DESCRIPTION
The Ronan Series X90 Point Level Monitor economically and reliably solves many process problems in which noise, temperature, abrasive or corrosive conditions preclude the effective utilization of sonic, capacitative, float or other techniques. This is a non-contact system.
Normally, a small Cesium-137 radioisotope source is housed in a lead-filled shielding enclosure known as the source holder. This holder is equipped with a shuttering mechanism and the means for containing the radiation and collimating or directing the radiated energy toward the sensor, which is directly opposite the source along a line or level to be measured. Radiation in all directions is attenuated to a safe value by the lead shielding. The source holder is mounted on or adjacent to the vessel whose content it is desired to monitor.
When the source holder shutter is opened, radiant energy is directed toward the sensor. In the absence of the process, this sensor sees only a small amount of radiation but, when the process is present, a large percentage of this radiation is absorbed. This absorption of radiation by the process causes a change in the radiation at the sensor. When this occurs, a relay contact signals that the level change has been observed.
The passage of radiant energy through the process causes no contamination and cannot make the process or container walls radioactive. These systems may be used anywhere, including the food processing industries.
For most applications, all components of the system are externally mounted. Therefore, installation is simple and requires no major mechanical modification or down-time.
The standard Ronan Model X90-301(V) gamma switch uses Cesium-137 as the source of gamma rays. Cesium-137 is a 0.66 MEV gamma ray emitter with a half-life of 30 years. The radioisotope material is sealed in a double-welded, stainless steel capsule. The source type and strength (activity) supplied depends on the individual application, and is printed on the yellow and magenta caution label affixed to the 3 source holder. The standard source holder is lead-filled and equipped with a two-position ON/OFF shutter mechanism. The handle and shutter mechanism can, by means of a combination padlock, be securely locked in the OFF position during shipping, installation, storage or processdown intervals.
Well sources are supplied with actuator rods, which can be used to extend the source into the vessel or retract the source into the storage source holder.
CAUTION: Any malfunction of the source holder must be immediately reported to Ronan Engineering for repair or replacement of the source holder. Under no circumstances may the source holder be taken apart.
Should it be necessary to ship the source holder back to Ronan, contact Ronan Engineering for detailed shipping instructions.
A Geiger-Mueller tube is used as the sensor for detecting the gamma radiation. The G-M tube consists of a gas-filled cylinder with a central anode. The anode is connected via a high ohmic resistance to a dc voltage of 500 V. Conduction occurs when the gamma radiation ionizes the gas in the tube. Each ionizing event produces a pulse, the rate of these pulses being proportional to the field strength of the ionizing radiation, i.e., incident field intensity. The output of the G-M tube is processed by an electronic circuit in the X90-301(V) module and the material level is indicated by either an ALARM or NORMAL signal.
_____________________________________________
2.0 SPECIFICATIONS (STANDARD)
The X90 is a solid-state instrument available in two designs. The Model X90 Detector with integral electronics has a combined detector and switch assembly located at the vessel. The Model X90-1004 Detector with remote electronics module may be fieldlocated or remotely located in a control room
Detector: Integral: Geiger-Mueller tube Remote: Geiger-Mueller tube
Radiation at Detector: Integral: 0.1 mR/hr min.
Remote: 0.1 mR/hr min.
Detector Housing: Integral: 4” Schedule 40 carbon steel pipe (type 304 stainless steel also available); mount to flat plate bracket Remote: Type 304 stainless steel; explosion-proof housing; mount with conduit clamp
Housing Classifications: Integral: Class I, Division 1, Groups A, B, C, D; Class II, Division 1, Groups E, F, G Remote: Class I, Division 1, Groups A, B, C, D; Class II, Division 1, Groups E, F, G
Ambient Temperature Range: Integral: -40° to 185°F (-40° to 85°C) Remote: -40° to 185°F (-40° to 85°C)
Overall Length: Integral: 20” (50.80 cm) |
Remote: |
8” (20.32 cm) |
|
Approximate Weight: Integral: 37.4 lbs. |
(17 kg) |
Remote: 4.4 lbs. (2 kg) |
|
Power: Integral: 115/230 VAC ± 15%, 40/60 Hz Remote: 115/230 VAC ± 15%, 50/60 Hz
Power Consumption: Integral: 7 watts per alarm
Remote: 7 watts per alarm point
Relay Output: Integral: DPDT 3 A at 30 VDC; 3 A at 120 VAC Remote: DPDT 3 A at 30 VDC; 3 A at 120 VAC
Analog Output: Remote: 0-1 V
Failure Alarm: Integral: Included Remote: Included
Time Delay Range: Integral: 0.5 to 20 seconds (10 or 20 seconds normal); jumper-selectable Remote: .05 to 20 seconds (10 or 20 seconds normal); jumperselectable
Display: Integral: LED status indicator Remote: LED status indicator
Accuracy: Integral ± 1/8” Remote: ± 1/8” All equipment approved by CSA.
—————————————————————————
3.0 THEORY OF OPERATION
The Ronan Series X90 gamma switches provide an alarm signal whenever the radiation field intensity at the detector (G-M tube) changes by more than its predetermined value. The variation in the field intensity may be due to either a change in the level (at the limit), or a change in the density of the process material in the radiation beam path. In a typical arrangement, the X90 detects the level of liquid in a vessel when it has exceeded a predetermined limit. The level limit is defined by an imaginary straight line drawn from the source to the detector.
Figure 1: Source and Detector
When the feed valve is open, liquid is fed into the vessel and the liquid level rises. The liquid level will rise until it interrupts the gamma ray beam. There is then a change in the field intensity at the detector due to absorption by the process of some of the energy present in the beam, and the instrument puts out an alarm signal in the form of a relay contact changeover. This signal may be used to close the feed valve and/or activate an annunciator. As the liquid is used from the vessel, the level will fall, thus again exposing the detector to the gamma radiation and the feed valve will be opened when the contacts revert to normal.
This is an example of a high limit switch, i.e., the process level is not allowed to rise above a certain limit.
Conversely, the source and the detector may be lowered to below the liquid level and the system functions as a low limit switch, in which case the system will produce an alarm when the liquid level falls below this low limit. The liquid itself may be under pressure at high temperature or even corrosive, but its characteristics will not affect the switch, since the system components are outside of the vessel.
A time delay based on the measurement controls the interval between radiation level change and alarm. A hysteresis band about the required level prevents fluttering and spurious alarm situations.
3.1Optional Gaging Configurations
3.1.1Model X90-1004 Remote Probe: The Ronan Model X90-1004 Remote Probe (located on vessel) with the X90-301(V) switch electronics may be located in a general purpose or Division II location. This is the most widely used configuration. The X90-1004X is a high-sensitivity tube, which may be specified for very weak fields (0.1 mR/hr. or less).
3.1.2Model X90-1005 Integral Switch: The Ronan Model X90-1005 Integral Switch in a Model X90-1001XP housing is usually specified when the X90-301(V) switch electronics cannot be located in a general purpose or Division II area. It may be used when the vessel is easily accessible for calibration and maintenance.
The Model X90-1005 contains the G-M tube sensor and switch electronics on a single chassis and is mounted on or just off the vessel wall.
—————————————————————————
4.0 FUNCTIONAL OPTIONS
4.1 High-Limit Process Alarm
The Process alarm relay will change over when the level of process material rises above the set limit.
4.2 Low-Limit Process Alarm
The process alarm relay will change over when the process level falls below the set limit.
4.3 Failure Alarm
In the case of the high-limit switch, under normal conditions the G-M tube receives full radiation and produces an output. This output will fall, producing an alarm when either the radiation is interrupted by the process level rising to above the set limit or the G-M tube or its power supply fails. However, if the tube or power supply fails, a failure alarm will be actuated, indicating the problem is in the unit. If
the tube output does not indicate a minimum background value (due to a malfunction in the G-M tube or its power supply) the process (and failure, if used) relay automatically changes over, indicating an alarm condition.
The failure alarm will occur anytime the output from the tube is zero.
—————————————————————————
5.0 TIME DELAY OPTIONS
The basic time constant is 0.5 seconds to 40 seconds, depending upon the span setting. Additional time delays available are 0.1, 5, 10 and 20 seconds.
For most applications, the 0.1 second jumper is used. If false alarms occur, the time delay should be increased. The delay is selected by a plug-in jumper located on the electronics chassis printed circuit board.
5.1 Relay Contacts
Two Form-C (SPDT) contacts are provided. Contact ratings are 3 A at 30 Ddc or 120 Vac resistive. Other forms of contacts may be provided on request.
If both sets of contacts are to be used for the process alarm relay, jumper A10, B-11 and C-12 (located on the X90-301(V) printed circuit board or X90-1005 printed circuit board for the integral version.) For the integral Model X90-1005, 10A contacts are provided as standard equipment.
If one set of contacts is to be used for a failure alarm relay, D10, E-11 and F12 are jumpered.
—————————————————————————
6.0 CIRCUIT DESCRIPTION
The X90-301(V) and X90-1005 circuitry consists of a stabilized ± 12 V and 500 V power supply, a voltage integrator, comparator and logic alarms.
The output pulses from the G-M tube are fed through an emitter follower to the input circuit. The pulses are + 12 V, 200 microseconds wide.
The G-M tube output is integrated and amplified by the input circuit. The zero and span controls are used to generate a 0 to 1 V output for low to high level conditions.
This output is monitored using a simple VTOM across the test points, AMP and TP GRN. A comparator circuit will trip the relay circuitry at 0.9 V and reset at 0.2 V. Jumpers on the circuit board are provided to make the switch function as a high-level or low-level limit alarm.
Complete circuit schematics and wiring diagrams are provided at the end of this manual.
7.0INSTALLATION AND ELECTRICAL CONNECTION—GENERAL
All equipment manufactured by Ronan Engineering is carefully packaged and shipped to prevent shipping damage. Any discrepancies between shipping contents and invoice should be immediately reported to Ronan or the Ronan representative.
All Series X90 system components (source holder, integral switch and remote tube assembly) will tolerate normal industrial vibration. However, in cases where vibrators are attached directly to the vessel, the system components must be mounted on adjacent building framework or use special supports that provide a degree of isolation.
When the axis of the G-M tube is placed parallel to the surface of the process material and its side-facing source, relay contact changeover will be obtained when the set limit is exceeded by about one-half inch. When a coarser level limit is appropriate, a broad band of about five inches can be obtained by placing the detector axis perpendicular to the surface of the process material. In either case, an alarm is produced after the tube is obscured from (or exposed to) the radiation from the source.
Whenever possible, separate power sources should be used for the X90 and the alarm circuit. With this arrangement, the alarm will operate if the power to the X90 is interrupted (provided, of course, the alarm circuit has power available).
Local electrical codes must be followed for all wiring. All conduit entrances should be sealed to prevent condensed moisture or water from entering the enclosures. The cable used to connect the remote G-M tube should also be run through conduit. All explosionproof housing covers must be replaced when the system is in operation.
7.1 Remote Probe (X90-1004)
The G-M tube with X90-1004 driver board is placed in an explosion-proof housing. This assembly is mounted in position at the required level or point of measurement and connected to the X90-301(V) module by a four-conductor, shielded cable supplied by Ronan Engineering.
Refer to drawing number C-1369-K for wiring of the remote detector assembly and refer to drawing number C-1359-K for designation of terminals on the X90-301(V) module.
7.2 Model X90GPE
The X90-301(V) modules are plugged into X90GPE surface-mount, single chassis enclosures. Access to input/output and power connections are from the front, beneath a convenient, snap-on cover. Connections are located in a separate compartment of the chassis and removal of the
module is not necessary in order to change wiring. Grommeted holes are provided on the top and bottom surfaces of the chassis for cable entry and exit. Overall dimensions are 7.25” high X 4.5” wide X 5.75” deep (18.42 cm X 11.43 cm X 14.6 cm).
Refer to drawing number C-1359-K for terminal designations for power wiring and hook-up to the remote probe driver board.
7.3 Integral Model X90-1005
Refer to drawing A-1697-K for rear-panel input power wiring connections and relay contact wiring connections.
—————————————————————————
8.0 CALIBRATION CONTROLS
The following front-panel controls are used in the set-up procedure.
ZERO CONTROL is used to provide a zero voltage signal at TP-AMP with the process level below the point of measurement, under conditions of maximum radiation at the G-M tube.
SPAN is used to provide a + 1.0 voltage signal at TPAMP when the process level is above the point of interest, under conditions of no radiation on the G-M tube.
Three light-emitting diode (LED) DISPLAYS are provided. These indicators will signal normal and level alarm for process conditions and failure alarm.
The AMP TERMINAL is the output of the voltage integrator. This output increases as the radiation on the tube decreases and vice versa.
Calibration should be attempted only after all system components have been securely mounted in position and power and other connections made where required. Check also that the correct jumpers have been installed on the X90-301(V) or X90-1005 printed circuit board.
—————————————————————————
9.0 CALIBRATION—GENERAL
The output at the AMP terminal is a measure of level present at the detector. This reading will be minimum or near zero when the detector is fully irradiated (no process) and the maximum or near 1.0 V when there is process material between the source and the detector.
Therefore, for calibration any option, two voltage readings are generated: 0.0 V with no process between the source and the detector and + 1.0 V with process between the source and the detector.
9.1Calibration with Process Material
a)Switch on the power to the X90 and turn the shutter handle on the source holder to the ON position. Turn the SPAN control clockwise 20 turns; then 10 turns counterclockwise.
b)Lower the process level below the set limit and adjust the ZERO control so that the AMP terminal output is zero.
c)Raise the process level above the set limit and again measure the voltage at the AMP terminal.
d)Adjust the SPAN control to obtain a reading of + 1.0 V at the AMP terminal.
After the switch has been calibrated using the above method, the operation of the control relay, NORMAL and ALARM indicators should be checked by raising and lowering the process level about the set limit. If all these operate as required, the switch is considered calibrated.
9.2Calibration without Process Material
a)Turn the source holder shutter to the ON position.
b)Turn the SPAN control clockwise 20 turns; then 10 turns counterclockwise.
c)Take voltage reading at the AMP terminal. Adjust the zero control to obtain an average 0.0 V reading at the AMP terminal.
d)Turn the source OFF.
e)Adjust the SPAN control for an average + 1.0 V reading.
f)Turn the source back ON for operation.
9.3 Time Delay
If false alarms occur, increase the time delay by moving the delay jumpers on the printed circuit board to a higher value.
9.4 Response Time
The response time of the amplifier is 0.5 to 40 seconds, depending on the SPAN setting.
Device |
Install |
High limit switch |
High and G |
|
|
Low limit switch |
Low and G |
|
|
Process alarm only |
A-10, B-11, C-12 |
|
|
Process alarm and failure |
Failure relay and D-10, E-11, |
alarm |
F-12 |
Delays |
Select one: 0.1 sec., 5 sec., |
|
10 sec., 20 sec. |
|
|
Loading...