The HLI-106T type settlement monitoring static level gauge is a high-precision liquid level measuring instrument used to measure the relative settlement of various measurement points of foundations and buildings. It consists of components such as a liquid storage tank, an ultra-high precision core, a specially customized circuit module, and a protective cover. The settlement system is composed of multiple sensors of the same model, connected by vent pipes and liquid pipes between the storage tanks. The reference point is placed at a stable horizontal benchmark, and when the measurement point rises or falls relative to the reference point, it causes a change in pressure at each point. By measuring the change in sensor pressure, the rise and fall changes of each measurement point relative to the horizontal benchmark can be calculated.

   Application sites include large buildings such as hydropower station plants, dams, high-rise buildings, nuclear power plants, hydraulic hub projects, railways, subways, and high-speed rail.

I. Performance Characteristics

   1. Small size, accuracy of 0.2mm, resolution of 0.01mm, range of 0-500-2500mmH2O;

   2. Can be installed according to ground trends without the need for turning points, fully sealed structure can be buried underground;

   3. Wide temperature compensation (-40~85℃), working temperature can reach -40~125℃, suitable for various harsh environments;

   4. Measurement points do not require liquid surface flow; as long as there is a liquid surface pressure difference due to settlement, it can be reflected in real-time, providing stronger data real-time performance;

   5. The hardware has an RS485 interface, strong compatibility, can connect to a Zigbee module to achieve a Zigbee self-organizing network. It can also connect to a GPRS module for remote communication.

II. System Installation

   The differential pressure static level system includes a differential pressure static level gauge, a liquid storage tank, a base plate, pipe joints, a drying tube, a vent pipe, a liquid pipe, an extension pipe joint, and raw tape. During installation, after opening the package, first collect the documentation, then count the quantity, and categorize the items for easy installation.

   Installation accessories are divided into measurement pier installation accessories and wall-mounted installation accessories. The factory configuration is selected according to user requirements, please check for errors upon unboxing.

Pre-construction preparation work

   1. Sensors, wiring, brackets, wire end plugs, liquid storage tanks, data collectors, wiring, power supply

   2. Liquid and gas pipes (material is PU neutral) specifications 10*6.5 8*5.

   3. Wire trough, U-shaped clips for fixing wire troughs or 32 PVC pipes

   4. Expansion screws for fixing sensors

　　 5. Inner hex screws and inner hex wrenches 3# for fixing sensor brackets

　　 6. Total station or electronic level, for super level use

　　 7. 100M power cable, for AC use, impact drill, aviation plug.

　　 8. Hand drill, with battery, screwdriver bits

   9. Wire stripper, flat, cross, and star screwdrivers, 13/15 open-end wrenches, 25mm adjustable wrench, cutting knife, raw tape, electrical tape, voltmeter, 485 data cable, power strip, oil pump, one 12v battery, antifreeze, 10-meter signal extension cable

   10. Computer, spare sensor, zip ties

　　 11. Reflective vest, safety helmet, insulated shoes, headlamp

III. Construction Steps

Installation methods and precautions for the static level gauge:

   1. Find the horizontal reference work

   1) Use a total station or electronic level to measure the elevation of each settlement monitoring point. Based on the elevation data, determine the settlement observation points.

　　 2) Pay attention to the elevation of the first benchmark point, ensuring that the settlement observation point is at the same elevation as the benchmark point (i.e., on the same horizontal plane). The benchmark point can also be slightly higher than the settlement observation point (generally about 30% of the full range).

 2. Fixing equipment construction

   1) After confirming the calibration points, mark according to the distribution map of the points, fix the product base on the surface of the monitoring structure, drill holes with a φ12 national standard impact drill bit, with a hole depth of 10-12CM.

　　 2) After drilling, fix the φ8mm expansion screws on the base plate, tighten with a 14 open-end wrench (do not tighten the expansion), place the tightened expansion screws into the drilled holes, adjust the angle, use a copper hammer to tap into the holes, fix the position, and securely tighten the expansion screws with a 14 open-end wrench to make them expand.

　　 3. Fixing the benchmark point

　　 1) The benchmark point is located at the outermost end of a line, 25 meters away from the last measurement point, to stay away from the settlement monitoring range. If the site environment is good, it can be chosen to be on a fixed bedrock.

　　 2) When installing the benchmark point, pay attention to the height difference corresponding to the measurement points to facilitate smooth pressure flow. The monitoring point should be as close to the benchmark as possible on the same horizontal line.

   4. Installation of sensors

   1) Installation of measurement pier brackets

　　 The embedded base plate component includes a steel base plate and three stainless steel screws. This component should be embedded in the concrete of the instrument pier when establishing the static level measuring point instrument pier. The surface of the embedded base plate should be level with the concrete surface of the instrument pier. After inserting the embedded base plate component, use a level to ensure it is flat, keeping the three positioning screws vertical to the surface of the instrument pier. (See Figure 1)

　　 2) Wall-mounted bracket installation

　　 If it is inconvenient or unnecessary to build a concrete instrument pier in some cases (such as installation on the inner wall of a corridor), a cantilever triangular bracket made of angle steel can be used for rigid coupling with the measurement point. (See Figure 1)

   5. Installation of the liquid storage tank

   1) The differential pressure static level system uses PU pipes to connect various differential pressure static level gauges in series, finally connecting to two liquid storage tanks. The installation position of the storage tanks follows the reference point, with a standard distance of 40CM from the reference point, and must be more than 50CM above the entire line, which helps the liquid pressure differential flow.

　　 2) When connecting the reference point and the storage tank, there must be no right-angle bends, and a 45° gentle angle must be maintained to ensure the fluid's flow.

   5. Installation of fixed pipes

   1) The selected fixed pipe slot is made of 32 PU pipe or PVC pipe. (The actual material is chosen based on the site environment). Fix the liquid pipe, gas pipe, and communication cable inside the fixed pipe, and be careful during construction not to damage the communication cable and liquid pipe, ensuring normal operation of the equipment during subsequent testing and operation. After the pipe is installed, use U-shaped fixed clips to secure the pipes, with a fixed distance of 50CM, and so on.

   6. Cutting and connecting cables, liquid pipes, and gas pipes

   1) Installation and connection of communication cables

   When installing communication cables, pay attention to the consistency of the male and female connectors. Do not pull or push forcefully to avoid unnecessary damage to the connectors. After connecting the male and female connectors, tighten them clockwise.

　　 Dig a trench between each settlement test point to lay the connecting pipes. Prepare wrenches, sealing tape, water injection tools, liquid and gas pipes, antifreeze (freezing point -25℃), silicone oil, gas pipe joints, purified water, PVC steel wire soft hoses, reading instruments, and leveling tools for installation.

   7. Installation of gas pipes and liquid pipes

   1) The gas pipe is an 8*5 PU pipe, connected to the B head of the sensor. When cutting, ensure it is kept horizontal, with no slanted or corrugated edges.

　　 1.1 The function of venting is to keep all liquid surface pressures consistent. The entire pneumatic balance system should be interconnected and only connected to the atmosphere at one end (choose one of the two ends).

　　 1.2 According to the distance between each measurement point, cut the vent pipe and connect them all in series. The gas pipe at one end of the liquid storage tank of the static level system is connected to the drying pipe with a three-way joint, and the other end is connected with a right-angle elbow.

　　 2) The installation material for the liquid pipe is a 10*6.5 PU pipe, and the installation method is the same as above, connecting to the A port.

　　 Lay the connecting pipes in the order of the length of the pipe routes between each measurement point and connect them to each sensor. The material for the connecting pipes is transparent PU soft hose. After soaking in hot water, connect it to the liquid level connection of the storage tank, and then lock it with screws. When laying the pipes, ensure they are straightened and aligned, avoiding bends in the middle to ensure quick pressure transmission. The connecting pipes between static level gauges need to be calculated for optimal length to prevent insufficient length during settlement, which could cause looseness at the connection point with the storage tank and lead to leakage.

   8. The workflow for filling liquid

   When filling liquid, pay attention to the balance of water pressure, and ensure there are no air bubbles in the liquid pipe. If bubbles are found, they must be promptly eliminated, as they will affect the accuracy of the equipment. After filling, carefully check the time, and recheck 24 hours later to ensure no bubbles remain in the liquid pipe.

IV. Subsequent operation checks

   1) Use the reading instrument to read the values of each static level gauge to determine whether they are in the required suitable position (the liquid level of the static level gauge at the reference point and each settlement observation point should float to the middle value of the full range. If the reference point is slightly lower than the full range of each settlement observation point by about 30%, then the liquid level of the static level gauge at each settlement observation point should float to about 15% below the middle value, while the reference point should be about 15% above the middle value). If not sufficient, add liquid until the required level is reached.

　　 2) After the liquid is fully added, connect the gas ports of each static level gauge using gas pipes and joints (the joint has an internal thread end connected to the gas port, and the other end connects to the gas pipe). Seal the gas ports and liquid ports of the first static level gauge and the last static level gauge with plugs, and check whether the seals of each liquid and gas pipe connection are intact, ensuring they are completely sealed.

　　 3) Connect the data lines of each static level gauge. Protect them with PVC steel wire hoses and lay them in the pipe trench.

　　 4) Install the protective cover of the static level gauge, backfill the installation holes and pipe trenches to the compacted surface, and compact them. Record the installation position, number, weather, and personnel involved in the installation of each static level gauge.

　  5) Create a signboard and insert it at the installation position of the static level gauge and the position of the connecting pipe. In cases where the fill layer above the static level gauge is thin, the soil or gravel within a 1m range around the instrument should be manually leveled and compacted with small machinery, avoiding the use of large machinery for pushing and compacting. Assign a dedicated person to oversee the area to prevent damage to the static level gauge and the bus due to construction or natural factors.

　　 6) Zero calibration, take initial values for zero calibration, and archive them. Maintain a record of the installation of the static level gauge.

　　 7) Conduct tests according to testing requirements. If the connecting static level gauges use an automatic data collection system, after zero calibration, connect the power supply and data bus to the bus interface data collection module terminal, and set up automatic collection.

　　 5. On-site equipment debugging

V. After-sales service

   1) On-site after-sales service during the installation period. After the equipment arrives at the construction site, our company will arrange for technical personnel to arrive on-site within 2-3 working days after consultation, to carry out equipment selection, installation, debugging, system connection, normal communication, and other after-sales services, ensuring that normal data is provided on-site under the premise of the client's construction needs, providing real and reliable data support for normal construction.

　　 2) On-site after-sales service during the operation period

　　 After the equipment installation and debugging are completed, it enters the operation phase. During the operation period, if damage occurs due to construction or other reasons, resulting in equipment collection or sensor damage, our company promises the customer that...

　　 1. After the customer reports an issue, provide a verbal solution within 1-2 hours, and remote handling within 2-4 hours to restore normal data collection.

　　 2. If remote operation cannot resolve the equipment issue, after negotiation, our company will arrange for engineering technicians to arrive on-site within 2-3 working days to address the on-site issues and restore the collection system to normal operation.