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- Hydraulic interface for fire loops and manual shutdown
- Components rated to operate from -50 C to +85 C ambient temperature
- Simple hydraulic circuit and high quality components insure high reliability
XH5, Self-Contained Wellhead Alarm & Shutdown
- Indicates and holds the actual cause of shutdown
- Sensing pressures from 60psi to 20,000psi
- Hydraulic interface for fire loops and manual shutdown
- Two loop monitored electronic alarm inputs allows connecting external alarm sensors such as manual or telemetry shutdown
- Simple hydraulic circuit and high-quality components ensure high reliability
- Very low maintenance
- Five-year batteries included
- Single and dual pump models
- Single and dual pump models
- Single and dual pump models
Second Generation of Electronic-Hydraulic Alarm and Shutdown for the Oil and Gas Industry, with a more advanced and robust electronic design promises surpassing the amazing reliability of its predecessor.
- Suitable for Class 1 Hazardous Areas.
- Process status at a glance: With the switch-gauge indicating the actual reading and set-points, the operator knows the conditions of the process.
- A "Heart Beat" Green LED shows that the system is operating without problems.
- The "Test" function shows the operator the cause of the last shutdown even after the system has been "Reset". Then, after a few seconds the system tests each alarm LED indicator.
- Components rated to operate from -50°C to +85°C ambient temperature.
- Environmentally friendly. The hydraulic circuits are enclosed in a stainless steel box that holds any oil leakage to prevent ground contamination.
- High and low set-points are easily adjusted without the need for special testing equipment.
- All components accessible - easy maintenance.
- Intruder protection. The enclosure may be padlocked to prevent unauthorized access to the set points or internal components.
- Pressing "Reset" will restore production and provides a 30 minutes "grace period" for the pressure/temperature to return to normal - no "pull and pin" valves needed.
- No sliding seals means no risk of the device failing because of lubricants drying out, no need for periodic disassembling, cleaning and lubricating.
- Electronic circuit designed and built to the same standards and care of other reliable Axiom products.
XH5 Typical Application
XH5 USER’S MANUAL
SELF-CONTAINED, SINGLE PUMP WELLHEAD CONTROL PANEL
The XH5 self-contained system is a device designed and built for protecting oil and gas production wells. It includes a switch-gage to detect high and low pressures as well as hydraulic interface for fire detection and manual ESD.
The XH5 is self-sufficient and doesn’t need external sources of energy or supply pressure for keeping a wellhead open and protected. It uses hydraulic fluid for driving the surface and sub- surface valves and it has two separate hand pumps and dump valves for independent control of the SSV and SCSSV.
The detection of High and Low pressures is done by a switch-gage with adjustable contacts for detecting when the monitored pressure is out of acceptable limits. The switch-gage connects to an electronic module that indicates High and Low pressure conditions as well as initiates the shutdown when a pressure alarm is detected. The electronic circuits are fed by a battery module capable of keeping the system operating for five (5) years.
The XH5 is built to operate exposed to the elements as all hydraulic components are enclosed in a stainless steel box while the electronic circuits and battery module are enclosed in a separate compartment inside the stainless steel box. The front of the panel includes the gages and controls as shown in Fig.1 while the inside components are shown in Fig. 2. The –HE version also includes additional sealing and a chemical seal to protect the sensing gauge from process fluids.
Fig 1: XH5 Interface and controls
The XH5 is built to operate exposed to the elements as all hydraulic components are enclosed in a stainless steel box while the electronic circuits and battery module are enclosed in an explosion-proof box inside the stainless steel box. The inside components are shown in Fig. 2.
Fig 2: XH5 Enclosure’s Interior
INSTALLATION – PRELIMINARY STEPS AND TESTS
The XH5 is sent with the battery module not mounted to prevent the system from operating while in transit. Also, as needed to meet shipping regulations, the device is typically shipped without hydraulic fluid in the reservoir and without Nitrogen pre-charge in the accumulators.
Before installing the system, it is to be inspected to confirm that there is no external damage or indication of rough handling during shipment.
In case of overseas shipments, it is recommended that the XH5 is tested in a workshop near the final destination to facilitate the commissioning and allow the operators to become familiar with the unit.
It is recommended that the operator becomes familiar with the Hydraulic Schematic (Appendix “B”) and have a copy handy during the tests described below to better understand the system’s behavior.
To commission the system follow with the steps listed below:
- Pre-charge 20 CU IN diaphragm accumulator with 500 psi of Nitrogen
- Pre-charge 5 CU IN diaphragm accumulator with 40 psi of Nitrogen.
- Add hydraulic fluid to the reservoir, approximately one gallon if reservoir is empty. Filling is to be done with care not to exceed the “High” level mark in the liquid gauge.
- Open Electronic Compartment inside the stainless steel box and install battery module as indicated in Appendix “A”. By doing this, the electronic circuit becomes energized and the green LED blinks every second (Heartbeat) to indicate the electronic circuit is operating without problem.
- Before applying pressure, it is recommended that hydraulic fluid is circulated throughout the system to flush any particle and contaminants that could be present within the hydraulic lines. With this purpose proceed as follows:
- Set valve “In Service – ESD” to “ESD”.
- Set valve “SSV - Pilot” to “Pilot”.
- Pump “Pilot/ SSV” in a fast mode for approximately one minute while observing the “Pilot” pressure gage. This gauge should display “0” psi but the needle oscillates with each pump strike.
- Set valve “SSV – Pilot” to “SSV”.
- Again, pump “Pilot/ SSV”in a fast mode for approximately one minute while observing the “SSV” pressure gauge. This gauge should stay in “0” psi.
- Confirm that the plugs on the bulkhead connectors are tight before proceeding with the following steps.
- Set valve “In Service – ESD” to “In Service”.
- Set valve “SSV - Pilot” to “Pilot”.
- Press “Reset” on switch “Test – Reset”.
- Pump “Pilot/ SSV” while observing the “Pilot” pressure gauge. Pump until reaching 80 psi. Inspect hydraulic lines to confirm that there is no leakage.
- Set valve “SSV - Pilot” into “SSV”.
- Pump “SSV - Pilot” pump while observing the “SSV” pressure gauge. Pump until reaching 1,500 psi. Inspect hydraulic lines to confirm that there is no leakage. It is normal for the pressure to fall about 10% after finishing the pumping.
- Set valve “In Service – ESD” to “ESD” to return all pressures to zero before moving the XH5 to the field for installation.
Typically the XH5 is mounted on one or two poles made of 3” pipe. Using two poles is preferred as it would ensure safe mounting even if one of the pipe brackets used for fastening the panel to the poles would fail. The two poles should have a separation of 10” to 15” (25cm to 38cm) center to center. The pipe brackets connect to the strut channel mounted on the left side of the panel.
With the panel firmly mounted, proceed to connect the field devices to the rear of the panel.
The connection to the ESD station can be also connected to a fire plug. If the fire plug used does not have a return line, some means are to be used to prevent hydraulic fluid from reaching the ground. A small amount of hydraulic fluid (approximately 3 CU IN or 50 CC) will be released in the event of the fire plug responding to a fire.
OPERATION AND ADJUSTMENTS
The operation of the installed panel is as follows:
1- Set valve “In Service – ESD” to “In Service”.
2- Set valve “SSV - Pilot” to “Pilot”.
3- Press “Reset” on switch “Test – Reset”.
4- Pump “Pilot/ SSV” while observing the “Pilot” pressure gauge until reaching 60 psi.
5- Set valve “SSV - Pilot” into “SSV”.
6- Pump “SSV - Pilot” pump while observing the “SSV” pressure gauge. Pump until reaching 1,500 psi. It is normal for the pressure to fall about 15% after finishing the pumping. Do not exceed maximum actuator’s pressure.
7- Check all hydraulic connections (internal and external to the panel) to confirm that there is no leakage.
8- Adjust High and Low Alarm set point on switch-gage.
9- Turn “In Service – ESD” valve to “ESD”. The system responds closing the SSV.
Re-opening the SSV:
10- If any of the red LEDs are flashing Press “Reset”. The Alarm LED stops blinking while the green LED (Heartbeat) blinks every two seconds.
11- If “In Service – ESD” valve is on “ESD” turn it to “In Service”
12- Set valve “SSV - Pilot” to “Pilot”.
13- Pump while observing the “Pilot” pressure gauge until reaching 80 psi.
14- Set valve “SSV - Pilot” into “SSV”.
15- Pump “SSV - Pilot” pump while observing the “SSV” pressure gauge. Pump until reaching 1,500 psi. It is normal for the pressure to fall about 10% after finishing the pumping. Do not exceed 2,000 psi.
Adjusting High and Low Pressure Alarms:
16- Turn red knob to adjust High pressure Alarm to the desired High Pressure Alarm. Repeat the same with the black knob to set the Low Pressure Alarm.
The hydraulic circuits are shown on appendix “B”.
WARNING – EXPLOSION HAZARD
SUBSTITUTION OF COMPONENTS MAY IMPAIR SUITABILITY FOR CLASS 1, DIVISION 2
DO NOT DISCONNECT EQUIPMENT OR REPLACE COMPONENTS UNLESS POWER HAS BEEN SWITCHED OFF OR THE AREA IS KNOWN TO BE NON-HAZARDOUS.
By replacing most of the hydraulic logic with electronic circuits, the most failure prone components are removed and the hydraulic circuit greatly simplified to a few reliable components. In this way, by having self-diagnostics in the electronics and a simplified hydraulic system, the XH5 offers a reliability level not seen on any of the typical self-contained wellhead control panel. Furthermore, if a failure would occur, the diagnostic and correction of the problem is much simpler because of the simplicity of the hydraulics.
Fig 3: External Alarm Termination Box
When operating under normal conditions (no alarms) the electronic system flashes the green LED every second (heartbeat) to indicate that the electronic system is operating without problems.
The connections to each of the remote alarms are through a single pair of wires and the remote signal may be a “dry” contact or an open collector or open drain of a transistor that would “pull the signal to ground” when the alarm is present. The End of Line Zener that is mounted on the External Alarm Termination Box must be removed from there and connected in parallel with the alarm device.
When connecting external alarm signals such as “Aux. Remote Shutdown” or “Telemetry Shutdown” remove the End of Line Zener Diode and run the wiring to the remote device (i.e. submersible electric pump control panel) and install the End of Line Zener in parallel to the dry contact.
If any alarm is detected the green LED stops flashing, the solenoid valve trips to initiate shutdown and the red LED corresponding to the detected alarm starts flashing. Once detected, the detected alarm is latched in such way that even if the alarm would go away or a new alarm would be detected; only the first alarm detected will flash, holding the information for the operator to see the cause of the shutdown. For example, if a High Pressure Alarm would occur the corresponding High Pressure Alarm LED will flash and keep on flashing even if the high pressure alarm would go away and now the gage’s needle is now touching the Low Pressure contact. The first detected alarm will keep flashing until the operator presses “Reset”.
Once the operator presses “Reset” the system resets the solenoid valve to allow the re-opening of the well and flashes the green LED even if the alarm still present. However, the pending alarm red LED and the green LED will flash alternatively to show the system is not completely clear. The system tolerates the existing alarm for 30 minutes before re-initiating the shutdown preventing the well from flowing for an unlimited period of time under alarm condition.
When pressing “Test”, the system respond by flashing the last detected alarm for about two seconds and then it sequentially flashes all five red LEDs to confirm all indicator LEDs are operating without problem.
The battery module provides two separate voltages, 3.6 VDC to feed the microcontroller circuits and 14.4 VDC to operate the solenoid valve and read the remote alarms. Both voltages are periodically monitored to confirm the system has the proper battery supply to operate reliably.
If the battery module shows sign of being discharged then the Green LED and the “Low Battery” red LED will flash alternatively to indicate the need for replacing the battery module. This warning may last for weeks but the operator must replace the battery module as soon as the above alternating LED flashing is detected. If the battery module discharges to the point where the electronics is no longer reliable, it will execute a shutdown for preventing operation under such low voltage condition.
See the instructions shown on Appendix “A” for installing the battery module.
Given the safety requirements associated with the XH5, enhanced self diagnostics have been added to insure the integrity of the system and the reliability of the operation.
To this effect, the XH5 monitors the wiring integrity of all alarms circuits including the High/Low Pressure alarm gauge and the loop integrity to the remote alarms located external to the XH5 enclosure.
As shown on Fig. 4, the XH5 is shipped with the End of Line Zener connected at the external alarms input points. When connecting the XH5 to an external alarm device, the End of Line Zener is to be removed from the Operator Interface Module and connected in parallel with the external alarm device.
Please note that, when connecting the End of Line Zener, polarity is important for proper operation. If the End of Line Zener is connected backwards it will cause the corresponding alarm channel to go into and remain on alarm condition.
If the End of Line Zener is disconnected or the wiring to the external alarm signal would fail, then the XH5 will read a “wiring failure” where the corresponding alarm LED would double flash and XH5 is initiated.
TO REDUCE THE RISK OF IGNITION OF HAZARDOUS ATMOSPHERES:
Do not open this enclosure unless the area is known free of ignitable mixture of gases.
Keep tightly closed when in operation.
Battery Module is to be replaced only with Axiom Part No. AT00000001 (Former AT-LBP-36144) battery module.
XH5 - ENVIRONMENTAL SPECIFICATIONS
Temperature range : -40 to +85C
Humidity range : 0 To 95% max., non condensing
Altitude : 2,000 m. max.
Hazardous Area Classification : Suitable for Class I, Division 2, Groups C & D, Hazardous Locations. Temp. Code T3C
XH5 - PRESSURE RATINGS
Sensing Pressure : Ranges of up to 20,000 psi max
Solenoid Valve Pressure : 100 psi max. (standard)
XH5 - ELECTRICAL RATINGS
Electrical Source : Dual voltage lithium battery module 3.6 & 14.4 VDC
Current consumption : 20 mA max. on 3.6VDC Circuits,
0.5 mA (3 A max. pulse) on 14.4VDC Circuits
THIS APPARATUS IS SUITABLE FOR USE IN A CLASS 1, DIVISION 2, GROUP C, D OR UNCLASSIFIED LOCATIONS
APPENDIX "A" BATTERY MODULE INSTALLATION
APPENDIX "B" HYDRAULIC SCHEMATIC
APPENDIX "C" - XH5 INSTALLATION NOTES