A pressure drop in the fire water supply below the calculated value of 1.0 MPa during operation of the PNS 110 station is a critical signal about the need to immediately check the hydraulic part of the system. Often the cause is airing in the suction pipeline or wear on the impellers of centrifugal pumps, which directly affects the ability of the system to supply the calculated volume of fire extinguishing agent to the source of fire.
Efficiency fire pumping station directly depends on the correct selection of equipment and quality of installation. Model PNS 110 is a complex engineering system designed to provide automatic fire extinguishing in buildings of various heights and purposes.
In this material we will analyze key technical parameters, features of hydraulic calculations and common errors during operation. Competent service pumping equipment guarantees its readiness to work in an emergency situation, when every second counts.
Design features and purpose of PNS 110
The basis of the station are cantilever-type centrifugal pumps, which provide the necessary pressure and water supply. Comes as standard PNS 110 Usually there are two main pumps (working and standby) and one jockey pump to maintain pressure in standby mode.
The frame structure is made of steel profiles with anti-corrosion coating, which allows the equipment to be installed directly in the pumping room without additional foundations. All piping elements, including shut-off valves and check valves, are selected taking into account the maximum operating pressure of the system.
- 🔥 The main pump provides water supply in case of fire with high productivity.
- 💧 The jockey pump compensates for micro-leaks and maintains static pressure.
- ⚙️ The control cabinet automates the process of starting and switching between units.
- 🛡️ Check valves prevent reverse water flow and water hammer when stopped.
It's important to note that hydraulic diagram may vary depending on the specific building design. However, the basic principle of operation remains unchanged: when the outlet pressure drops to a threshold value, the controller sends a signal to start the main unit.
⚠️ Attention: Installing a pumping station without vibration isolators can lead to destruction of pipelines due to transmitted vibration.
Specifications and operating range
The PNS 110 range covers a wide range of performance requirements. The nominal water supply can vary from 30 to 300 m³/h, and the maximum pressure can reach 160 meters of water column. Such parameters make it possible to use stations for water supply to high-rise buildings and industrial facilities.
Electric motors mounted on the frame have a protection class of at least IP54 and insulation class F, which allows operation in conditions of high humidity and dust. The power of the motors is selected individually according to the hydraulic characteristics of the pump and can range from 15 to 90 kW.
To accurately select equipment, the following must be taken into account: system parameters:
| Parameter | Value/Range | Unit of measurement |
|---|---|---|
| Nominal feed | 30 - 300 | m³/h |
| Maximum head | up to 160 | m |
| Engine power | 15 - 90 | kW |
| Mains voltage | 380 ± 10% | B |
| Ambient temperature | +5 ... +40 | °C |
When choosing a model, you should pay attention to the performance curve. The operating point should be in the middle of the efficiency curve to ensure maximum energy efficiency and minimal wear on components.
Operating principle of the automation system
The station is controlled via control cabinet, which receives signals from pressure sensors installed on the pressure manifold. The operating algorithm is based on the priority of the main pump and automatic activation of the backup pump in the event of failure of the first one.
Modern controllers allow you to configure various operating scenarios, including “fire”, “training” and “emergency” modes. When switching to mode fire fighting the ability to manually stop the pump is blocked until the fire alarm signal is reset.
Key functions of the automation system:
- 🔄 Automatic alternation of operation of the main and reserve pumps for uniform wear.
- 📉 Smooth start of motors to reduce starting currents and water hammer.
- 🛑 Protection against dry running and overheating of electric motor windings.
- 📡 Remote transmission of work status to the dispatcher console.
Pressure setpoints must be adjusted by qualified personnel using calibrated pressure gauges. Erroneous values can lead to false starts or, conversely, to a delayed system response.
Setting up the frequency converter
For PNS with frequency regulation, it is important to correctly configure the PID controller. Settings that are too aggressive will lead to pressure swings, while settings that are too soft will result in a slow response to fire water supply.
Requirements for installation and wiring
Installation quality fire station determines the reliability of the entire fire water supply system. The suction pipeline must have a constant slope towards the pump to prevent the formation of air pockets. The diameter of the suction pipe is usually taken 1-2 standard sizes larger than the diameter of the pump inlet pipe.
A check valve and shut-off valves must be installed on the suction line. A coarse mesh filter is installed before entering the pump, which protects the impellers from foreign objects, scale or stones.
When installing a pressure manifold, it is necessary to install:
- 📏 Control and measuring instruments (pressure gauges) before and after shut-off valves.
- 🚰 Test valve with a pipe for draining water into the sewer.
- 🔊 Devices for damping water hammer (hydraulic accumulators or valves).
- 🔧 Flange connections with the possibility of dismantling for maintenance.
⚠️ Attention: The use of plastic pipes in the pressure section of the fire water supply is strictly prohibited by regulations.
After completion of installation work, a hydraulic test of the system is carried out under pressure exceeding the working pressure by 1.5 times. Only after successful pressure testing and flushing of pipelines is commissioning of equipment allowed.
☑️ Checklist before the first launch
Scheduled maintenance and diagnostics
Regular Maintenance PNS 110 extends the service life of equipment and ensures its availability. It is necessary to visually inspect the station weekly for leaks, extraneous noise and vibration. The position of the pressure gauge indicators in static mode is also checked.
Deeper checks are carried out quarterly, including spinning the pump shafts (if they have not been in operation), checking the oil seals and lubrication of the bearing units. Once every six months, it is recommended to test run the pumps in operating mode with water discharged through a test valve.
Typical malfunctions and methods for eliminating them:
- 🔇 The pump hums, but does not pump - check for air in the system or the filter is clogged.
- 📉 Pressure drop during operation - wear of impellers or opening of additional water intake.
- 🔥 Engine overheating - violation of shaft alignment or operation in overload mode.
- ⚡ Frequent activation of the jockey pump means a leak in the fire extinguishing system.
Keeping a maintenance log is a mandatory fire safety requirement. The log contains the dates of inspections, the results of current and pressure measurements, as well as information about repairs performed.
Tip: To prevent sticking of the moving parts of the shut-off valves, periodically (once a month) completely close and open them.
Performance calculation and equipment selection
Selecting a specific modification PNS 110 is based on hydraulic calculations performed at the building design stage. The number of simultaneously operating sprinklers in the sprinkler system or deluge sprinklers is taken into account, as well as the flow rate for internal fire hydrants.
The required pressure consists of the geometric height of water rise (to the most distant sprinkler), pressure losses in the pipelines and the free pressure required for the operation of the sprinkler. The headroom is usually 10-15% to compensate for hydraulic resistance and changes in operating conditions.
The calculation also takes into account the fire hazard category of the premises. For warehouses with a high fire load, the required irrigation intensity will be significantly higher than for office premises, which directly affects the choice of power pumping unit.
Errors in the calculation can lead to two scenarios: insufficient fire extinguishing efficiency or cavitation wear of the pump due to operation in an inappropriate mode. Therefore, double-checking the source data before purchasing equipment is a critically important step.
⚠️ Attention: Independent recalculation of system parameters without a license from the Ministry of Emergency Situations and the design organization is prohibited.
Main conclusion: Correct selection of PNS 110 and regular maintenance are the only guarantee that the system will work at a critical moment.
FAQ: Frequently asked questions
How often should the water in the fire extinguishing system be changed?
The water in the system must be clean and non-aggressive. A complete replacement is required only after repair work or if a water analysis shows an excess of hardness salts, which can lead to overgrowing of pipes. Usually the water is simply monitored and filtered if necessary.
Is it possible to use PNS 110 for domestic and drinking water supply?
Absolutely not. The water in the fire extinguishing system is technical and does not comply with SanPiN standards for drinking water. In addition, drawing water from a fire system for domestic use is prohibited by law.
What to do if the pump turns on more than 5 times per hour?
Frequent switching on indicates a leak in the system (malfunction of valves, fistulas in pipes) or incorrect setting of the on/off pressure of the jockey pump. It is necessary to audit the system for water losses.
What protection class should the PNS electric motor have?
For pumping station rooms that may be flooded when extinguishing a fire or have high humidity, it is recommended to use motors with a protection class of at least IP54, and in some cases IP55.