Swing Check Valve With Hammer HH44T

Swing Check Valve With Hammer Definition and Components

Inspection Checklist:

• Functional Swing Test: This is key. Hold the valve in its installed orientation (disc hinge horizontal). The disc must swing freely and fully open by its own weight when the valve body is tilted, and fall closed smoothly without sticking.
• Pressure Testing: Perform shell test and seat leakage test per API 594. For a metal-seated valve (bronze-on-metal), a slight weep per the standard is acceptable, but major leakage is not.
• Dimensional Check: Verify face-to-face length and flange dimensions/drilling against the order specification.
• Visual Inspection: Check for proper machining of the seat face and absence of defects in the disc sealing surface.

Export Precautions:

• Secure the Disc: Before crating, tie the disc in the fully closed position using wire or plastic straps. This prevents it from swinging violently during handling and damaging the hinge pin or seat.
• Protect Flange Faces: Use sturdy, bolted plastic or wooden covers on the flange faces to protect the sealing surfaces and bolt holes.
• Internal Preservation: Apply a light, removable anti-corrosion coating to internal metal surfaces, especially the disc and seat.
• Proper Packaging: Use a robust wooden crate. Due to the valve's asymmetric weight distribution (the disc and cover assembly), ensure it is blocked and braced to prevent movement. Mark the crate with "SWING CHECK VALVE" and "KEEP HORIZONTAL" handling instructions.

Role, Characteristics, and Application Scenarios of Swing Check Valve With Hammer in Pipelines

Water supply valve Pipeline Functions:

• Positive Backflow Prevention: Standard check valve function.
• Controlled, Forced Closure: The external weight ensures the disc closes firmly and decisively, even under low reverse pressure or in the presence of flow disturbances that might cause a standard swing check to chatter or remain partially open.
• Disc Flutter Prevention: The added inertia dampens oscillations.

Operational Features:

• Adjustable Closing Force: The position of the weight on the lever arm is adjustable, allowing tuning of the closing speed and force to match system dynamics.
• Ensures Tight Seal: Provides additional seating force, improving shut-off compared to gravity-alone designs.
• External Mechanism: Requires more space and is more susceptible to environmental damage/corrosion than an internal design.
• Horizontal Installation Only: Must be installed with the lever assembly oriented correctly (typically upwards).

Application Scenarios:

Used in systems where a standard swing check valve is unreliable due to slow flow, low backpressure, or pulsating conditions that cause disc flutter.

• Low-Flow or Low-Pressure Pump Discharge: Ensures closure when reverse pressure is minimal.
• Compressed Air/Gas Systems: Prevents flutter in pulsating flow.
• Vertical Pump Discharge (into overhead lines): Where the disc might not close reliably by gravity alone due to line geometry.
• Steam Return Lines: To ensure positive closure.

Check Valve for Water Scenario Diagram (Text Description):

In an industrial compressed air system, a reciprocating compressor sends pulsating air flow into a receiver tank via a horizontal pipeline. A standard swing check valve on the discharge would chatter violently with each compressor stroke. Instead, an HH44T Swing Check Valve with Hammer is installed. The adjustable weight on the external lever is set to provide significant closing force. When the compressor piston stops on its return stroke, the weighted lever immediately and forcefully slams the disc shut against its bronze seat, preventing backflow into the compressor cylinder. This action happens consistently with every stroke, eliminating damaging flutter and ensuring efficient operation, even though the forward air pressure might be relatively low at the moment of closure.

Swing Check Valve With Hammer Standards: Materials, Design, and Connections

Material Standards:

• Body & Cover: Cast Iron (ASTM A126), Ductile Iron (ASTM A536).
• Disc: Bronze or Cast Iron.
• Seat Ring: Bronze (ASTM B62).
• Lever Arm & Weight: Carbon Steel, often galvanized.
• Shaft Extension: Stainless Steel.

Design Standards:

• API 594: Check Valves: Flanged, Lug, Wafer, and Butt-welding.
• ASME B16.34: Valve Pressure-Temperature Ratings.
• MSS SP-71: Cast Iron Swing Check Valves.

Connection Standards:

Flanges: ASME B16.1 Class 125/250, Raised Face (RF).

How to Select Swing Check Valve With Hammer

Key Steps:

• Identify the Need for Forced Closure: Specify this valve if system analysis indicates problems with disc flutter, slow closure, or unreliable sealing with a standard swing check.
• Specify the Weight Setting: Provide the desired closing characteristics or system data (flow rates, pressures) so the manufacturer can pre-set the weight position. Ensure the lever and weight are sized for the valve.
• Consider the Environment: The external mechanism is exposed. For corrosive or outdoor environments, specify appropriate coatings or materials for the lever and weight.
• Verify Space and Orientation: Confirm there is adequate clearance for the lever to swing freely and that the installation will be horizontal.

Pre-Shipment Inspection for Export Swing Check Valve With Hammer and Key Considerations

Inspection Checklist:

• Lever & Weight Function Test: This is critical. Operate the valve manually through the lever. It must swing freely. The weight should be securely attached but adjustable. Check that the lever moves the internal disc smoothly.
• Pressure Testing: Standard shell and seat leakage tests per API 594.
• Mechanical Integrity: Inspect welds or fastenings on the lever arm, weight, and shaft extension for defects.
• Free Movement: Ensure the internal disc is not binding and moves in sync with the external lever.

Export Precautions:

• Immobilize the Lever: The lever arm must be securely fastened in the valve's closed position using metal strapping or bolted blocks to the valve body. This prevents the heavy weight from swinging during transit, which could damage the shaft or hinge.
• Protect External Parts: Coat the lever, weight, and shaft extension with a heavy-duty, weather-resistant grease or paint to prevent rust during ocean shipping.
• Clear Marking: Mark the crate with "LEVER CHECK VALVE - SECURE LEVER DURING TRANSPORT" and indicate the top side. Include clear instructions for removing the transit restraints before installation.
• Packaging: Use a strong wooden crate. The external lever makes the valve asymmetrical and prone to tipping. Use substantial blocking and bracing to keep the valve fixed in the crate.

Swing Check Valve With Hammer Main dimensions(mm)

DN	D	D1	L	b	Z-d	H
11/2”	127	98.5	165	15	4-Ф16	120
2”	152	120.5	203	16	4-Ф19	137
21/2”	178	139.5	216	17.5	4-Ф19	143
3”	191	152.5	241	19	4-Ф19	154
4”	229	190.5	292	24	4-Ф19	171
5”	254	216	330	24	8-Ф22	204
6”	279	241.5	356	25.5	8-Ф22	219
8”	343	298.5	495	29	8-Ф22	258
10”	406	362	622	30.5	12-Ф25	290
12”	483	432	698	32	12-Ф25	325
14”	533	476	787	35	12-Ф29	361
16”	597	540	914	37	16-Ф29	388
18”	635	577.9	927	39.7	16-Ф32	450
20”	699	635	956	43	20-Ф32	518
24”	813	749.5	1118	48	20-Ф32	620

Swing Check Valve With Hammer Main part material

No.	Part Name	Material	Standard
1	Body	Cast iron/Ductile iron	ASTM A126B
2	Body Seat Ring	Bronze
3	Disc Seat Ring	Bronze
4	Disc	Cast iron/Ductile iron	ASTM A126B
5	Washer	Carbon Steel	A3
6	Nut	Carbon Steel	A3
7	Cotter Pin	Stainless Steel	SS304
8	Arm	Ductile iron	ASTM A536
9	Hing Pin	Brass
10	Plug	Carbon Steel	A3
11	Gasket	NYL
12	Gasket	NBR	ASTM D2000
13	Bonnet	Cast iron/Ductile iron	ASTM A126B
14	Bolt	Carbon Steel	A3
15	Gland	Ductile iron	ASTM A536
16	Hinge	Ductile iron	ASTM A536
17	Hammer	Cast iron/Ductile iron	ASTM A126B

 Note:1. Other specifications and flange standards are available upon request.

2. Design and specifications are subject to change without prior notice.