DCT25 Dry Alarm Valve
Devinsan offers specialized fire protection solutions engineered for reliable operation and structural safety in environments susceptible to freezing temperatures. Designed for immediate system activation and continuous air pressure supervision, these DCT25 Dry Alarm Valve units utilize a pressure differential clapper mechanism to meet the crucial demands of modern commercial and storage facility life safety networks.
Production Standard
Nominal Dimension (DN)
Nominal Pressure (PN)
Operating Temperature
Connection
Coating
Testing
DN 40 – DN 200
PN 6-PN 10-PN 16
-30° / +200°
EN 1092-2 ISO7005-2 Flanged
Electrostatic Powder Epoxy
TS EN 14384
Application Areas
The DCT25 Dry Alarm Valve is widely used across diverse industrial and commercial sectors, delivering reliable flow control and long‑lasting performance.
1. Water and Wastewater Systems
2. Chemical Industry
3. Food and Beverage Industry
4. Pharmaceutical Industry
5. Oil and Gas Industry
6. HVAC (Heating, Ventilation, Air Conditioning) Systems
In these applications, this type DCT25 Dry Alarm Valve ensures precise fluid control, maintains excellent sealing integrity, and supports efficient, safe operation even under demanding conditions.
The DCT25 Dry Alarm Valve is a critical component specifically engineered to control the flow of water into a dry pipe sprinkler system and simultaneously initiate alarms upon activation. Designed to meet the stringent safety demands of modern infrastructure, this specialized valve ensures rapid system pressurization, outstanding durability, and continuous protection against freezing by keeping the sprinkler piping filled with pressurized air or nitrogen.
At the core of the DCT25 Dry Alarm Valve is its mechanically latched clapper assembly, which holds back the water supply using supervisory air pressure maintained in the sprinkler piping. When a sprinkler head activates due to heat, the air pressure rapidly drops. The higher water pressure instantly overcomes the remaining air pressure, lifting the clapper to allow water to flood the system and simultaneously activate the local water motor gong and electrical alarms.
Manufactured from high-strength, corrosion-resistant materials (such as cast iron) and built with a robust, heavy-duty body, the DCT25 Dry Alarm Valve is designed to withstand continuous system pressure and the dynamic forces of rapid system activation. Its standard flanged connections allow for secure integration into the main sprinkler riser. The critical function of this valve is to bridge the air-water gap safely until the moment of fire suppression.
The DCT25 Dry Alarm Valve is ideally suited for deployment in unheated warehouses, loading docks, freezer storage facilities, and any structure where the sprinkler piping is exposed to freezing temperatures. Its proven activation mechanism and air-water differential design make it a preferred choice for engineers seeking a high-integrity, standards-compliant solution for long-term safety assurance in harsh climates.
In summary, the DCT25 Dry Alarm Valve offers an optimal combination of freeze protection, rapid air-pressure monitoring, and reliable water deployment. With its robust differential clapper mechanism, essential trim components, and durable construction, this unit stands as a trusted solution for modern fire protection and life safety requirements worldwide.
1. General Information
The DCT25 Dry Alarm Valve is designed for installation on the main riser of a dry pipe sprinkler system, requiring connection to the water supply and an air pressure source. Proper installation is essential to guarantee safe operation, long service life, and reliable alarm function.
2. Safety Precautions
Installation must be performed by qualified personnel only, typically licensed fire protection contractors.
Ensure strict compliance with all local fire codes, NFPA standards, and safety regulations concerning connecting to pressurized fire water mains and compressed air systems.
Wear appropriate personal protective equipment (PPE).
Confirm that the fire water main and the system air supply are isolated and depressurized before attempting to install the DCT25 Dry Alarm Valve.
3. Pre-Installation Checklist
Inspect the DCT25 Dry Alarm Valve for any visible damage during transport or storage, paying attention to the differential clapper and trim connections.
Check that the valve type, size, and pressure rating match the system requirements.
Verify that the valve interior and alarm port are clean and free from debris.
Confirm that the mating pipeline flanges are properly aligned (parallel and concentric) and free from burrs or sharp edges.
Ensure sufficient space is available around the valve for connecting the compressed air line, gauges, and external alarm trim.
4. Installation Procedure
Positioning: Install the DCT25 Dry Alarm Valve vertically on the main riser, ensuring the flow direction adheres to the arrow cast on the body.
The trim piping and accelerator (if used) must be installed according to the hydraulic schematic.
Use the appropriate gaskets suitable for the medium and operating conditions.
Align the valve precisely between the pipeline flanges and insert bolts, tightening them gradually and crosswise in incremental steps.
Connect the external alarm trim, air supply line, and pressure switches, ensuring all seals are tight.
5. Post-Installation
Slowly introduce water pressure to the supply side (below the clapper) and charge the sprinkler piping with supervisory air pressure, maintaining the required pressure differential.
Verify the pressure switch operation and test the water motor gong function to ensure reliable alarm activation upon system trip.
Record the installation details, set pressures, and final notes for documentation purposes.
Proper maintenance extends the service life of the DCT25 Dry Alarm Valve and ensures reliable system activation and freeze protection. Follow the guidelines below to maximize the longevity and readiness of this essential unit.
1. Routine Operation
Visually inspect the DCT25 Dry Alarm Valve and all associated trim piping regularly (e.g., weekly) for signs of external leakage, air leaks, or corrosion.
Check the air pressure gauge to ensure the supervisory air is maintained above the required set point to prevent the valve from tripping accidentally.
2. Inspection Schedule
Monthly, check the air pressure gauge to verify the pressure differential across the clapper is stable and correct.
Quarterly, check the cleanliness of the pilot line strainers and the system drain valves.
Annually, perform a mandatory “full flow trip test” by activating a remote test valve to ensure the dry alarm valve opens completely and water flows rapidly into the system.
3. Lubrication
The internal moving parts (clapper hinge) of the DCT25 Dry Alarm Valve are generally designed to be maintenance-free.
No external lubrication is required for the internal components.
4. Seal and Gasket Replacement
Replace the main clapper seal (gasket) and the housing gaskets immediately if internal leakage (clapper trip) is observed during static water pressure testing.
Trim piping seals should be replaced if external leakage is detected.
Always isolate the system water supply and fully bleed the pressure from both the water and air sides before attempting any maintenance work requiring cover removal.
5. Cleaning
Keep the exterior of the DCT25 Dry Alarm Valve clean to prevent surface corrosion.
Ensure the retard chamber and alarm line piping are flushed periodically to prevent sediment buildup that could inhibit alarm activation.
6. Storage and Spare Parts
Store spare parts (clapper seals, gaskets, pressure switches) in a dry, clean, and cool environment, away from direct sunlight and temperature extremes.
Maintain a detailed record of all inspections, trip tests, and repairs performed on the DCT25 Dry Alarm Valve unit.
We prioritize quality at every stage of production to deliver durable, safe, and efficient products. Our continuous improvement and strict quality controls keep us at the forefront of the industry.
Our certifications prove our commitment to excellence and compliance with international standards, ensuring the safety and reliability of our products worldwide.
We continuously invest in innovation and quality to expand our certifications and meet evolving industry needs.
Frequently Asked Questions about the DCT25?
What are the main advantages of this valve?
The DCT25 Dry Alarm Valve allows the sprinkler piping to be filled with air (instead of water), providing necessary freeze protection in unheated buildings while maintaining constant supervision and ensuring rapid water delivery when a fire is detected.
Why should I choose this product?
This valve delivers outstanding performance in both sealing and durability, making it a dependable choice for demanding applications. Its straightforward design facilitates easy installation, offering flexibility during system design. With a wide range of material options, it meets the needs of various infrastructure projects, from municipal water networks to industrial facilities.
What is the significance of the pressure differential in the DCT25 Dry Alarm Valve?
The pressure differential uses a small air pressure (e.g., 40 psi) to hold back a much larger water pressure (e.g., 100 psi) due to the large surface area of the clapper. When the air pressure drops slightly (sprinkler opens), the water pressure instantly forces the clapper open.
How does the DCT25 Dry Alarm Valve prevent false alarms?
The clapper mechanism is designed to be highly stable and resistant to minor water pressure fluctuations on the supply side, ensuring the dry valve only trips when there is a significant, sustained drop in the supervisory air pressure (indicating an actual activated sprinkler).
What is the typical ratio of water pressure to air pressure required to keep the DCT25 Dry Alarm Valve closed?
The typical pressure differential ratio is approximately 6:1. This means that 1 psi of air pressure in the system piping can hold back about 6 psi of water pressure on the supply side.
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