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DL41X Low‑Resistance Backflow Preventer Ductile Iron Flanged Anti‑Pollution Backflow Prevent Valve For Potable Water Supply Pipeline

DL41X Low‑Resistance Backflow Preventer Ductile Iron Flanged Anti‑Pollution Backflow Prevent Valve For Potable Water Supply Pipeline

The DL41X Low-resistance Backflow Preventer is mainly used for effective isolation in cross-connections
between urban water supply pipe networks and various user pipe networks, or between domestic drinking
water systems and heterogeneous water systems such as fire water, air conditioning water, and greening
water, so as to strictly control backflow contamination.

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Product Description

Technical Parameters Working Principle

1.Flanged connection shall comply with the standards GB/T 17241.1-2024 and GB/T 9124.1-2019.

2.Strength and sealing tests shall comply with the standard GB/T 13927-2022.

3.Relevant technical parameters are listed in Table 1, materials of main components in Table 2, overall

dimensions in Table 3

Table 1:Technical Parameters Table

PN

1.0MPa

1.6MPa

2.5MPa

Body Test

1.5MPa

2.4MPa

3.75MPa

Seal Test

1.1MPa

1.76MPa

2.75MPa

Temperature

0℃~80℃

Actuation Method

Self-actuated

Table 2:Main Component Materials
Part Name		Materials
Body,Bonnet,Seat,Disc		Ductile Iron/Cast SteelStainless Steel
Spring		Silicon-Manganese Steel/Stainless Steel
Sealing Ring		NBR/EPDM
Stem		Stainless Steel
Fasteners		Carbon Steel/Stainless Steel

DN	φD			φK			N-Q			L
	PN10	PN16	PN25	PN10	PN16	PN25	PN10	PN16	PN25
50	165			125			4-φ19(18)			269±2
65	185			145			4-Q¹9(18)		8-Q¹9(18)	279±2
80	200			160			8-Q19/18)			331±2
100	220		235	180		190	8-Q¹9(18)		8-Q23(22)	415±2
150	285		300	240		250	8-φ23(22)		8-φ28(26)	530±2
200	340		360	295		310	8-φ23(22)	12-Q23(22)	12-Q28(26)	646±2
250	395	405	425	350	355	370	12-φ23(22)	12-028(26)	12-031(30)	750±2
300	445	460	485	400	410	430	12-023(22)	12-Q28(26)	16-031(30)	860±2
350	505	520	555	460	470	490	16-Q23(22)	16-Q28(26)	16-034(33)	985±3
400	565	580	620	515	525	550	16-φ28(26)	16-031(30)	16-037(36)	1100±3

Features

1.This product features a unique design with ultra-low water loss, remarkable energy efficiency and minimalhead loss.

2.It boasts an aesthetic appearance, simple installation and convenient maintenance.

3.The double check valve combined with air gap thoroughly prevents backflow contamination under allworking conditions.

4.With precise calculation, excellent manufacturing quality, reliable performance and sensitive operation.

5.Air gap & automatic drainage: In the backflow state, when the main valve is closed, the drainer opens

automatically, the pressure in the intermediate chamber is relieved to zero, and an air gap or zero-pressure

isolation is achieved between the upstream and downstream of the main valve, ensuring safe and reliable

isolation performance.

6.Both internal and external surfaces are coated with an environment-friendly layer to ensure the corrosion resistance and safety of the product.

Application

Municipal potable water supply pipeline network
Building domestic water supply system
Residential district water supply project
Water plant outlet pipeline
Fire‑fighting water supply pipelines
Cross‑connection points between drinking‑water and non‑potable water systems

.

Precision Valve Manufacturing

Professional Valve Manufacturer | Integrated Manufacturing

Raw Material

We select high-quality raw materials according to product specifications and international standards. All incoming materials are carefully inspected to ensure chemical composition, mechanical properties and traceability.

Forging & Casting

Advanced forging and casting processes are used to produce strong and reliable valve bodies and components. Strict process control ensures uniform structure, dimensional accuracy and excellent mechanical performance.

CNC Machining

Our CNC machining equipment provides precise and consistent processing of valve components. Critical dimensions, threads and sealing surfaces are strictly controlled to ensure accurate assembly and reliable sealing performance.

Shot Blasting & Coating

Valve surfaces are professionally shot blasted to remove rust, scale and impurities. Protective coatings are then applied according to customer requirements, providing excellent corrosion resistance and a durable surface finish.

Pressure Testing

Every valve undergoes strict pressure testing before shipment. Body and seat tests are performed according to applicable standards and customer specifications to verify pressure resistance and sealing reliability.

Quality Inspection

Our quality control team conducts comprehensive inspections throughout the production process. Finished valves are checked for dimensions, appearance, materials, pressure performance and overall quality before final approval and shipment.

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