ball check valve

Spherical check valve is an automatic check valve with a spherical valve core as the sealing element. It relies on the pressure difference of the medium itself to drive the valve core to move, achieving the function of one-way flow and reverse flow blocking of the medium. Its compact structure, low flow resistance, and good sealing are widely used in industrial and civil pipeline systems such as water supply and drainage, petrochemicals, power, HVAC, etc. It is one of the key equipment for protecting pipeline operation.

Core structure and material selection

Overall structural composition

The spherical check valve adopts a straight through or angular structure design, with simple and functional core components, mainly including:

Valve body: Designed with a streamlined flow channel to reduce medium flow resistance, it is equipped with a valve core guide channel, a valve seat sealing surface, and inlet and outlet connection ends (supporting flange, thread, welding, and other connection methods) inside.

Spherical valve core: The core control component is usually a solid sphere (some large-diameter models use hollow spheres for weight reduction), with a surface that has been carefully processed to confirm roundness, and is sealed by its own gravity and medium pressure.

Valve seat: It cooperates with the spherical valve core to form a sealing pair. The valve seat material is divided into soft seal (rubber, PTFE) and hard seal (metal), and some models use replaceable valve seats for easy maintenance.

Guidance device: including valve core guide sleeve, limit pin, etc., to confirm that the spherical valve core moves along a fixed trajectory and avoid sealing failure caused by valve core displacement.

Spring (optional): Auxiliary springs are configured in low-pressure, low flow, or vertical installation scenarios to push the valve core to reset at a suitable speed, enhance sealing performance, and prevent medium leakage.

Working principle (pressure driven+gravity/spring reset)

The spherical check valve achieves automatic opening and closing through the balance of positive pressure and negative gravity (or spring force) of the medium, without the need for external power. The working process is as follows:

Positive opening: When the medium flows forward along the pipeline, the medium pressure acts on the front end face of the spherical valve core, overcoming the gravity of the valve core itself (and the spring force, if any), pushing the valve core to move backward along the guide channel, disengaging from the sealing surface of the valve seat, and the valve opens. At this point, the valve core is in contact with the flow channel, the flow channel is unobstructed, and the fluid resistance is low.

Reverse shutdown: When the water pump stops, the pipeline pressure drops, or the medium begins to flow back, the reverse pressure of the medium works together with the gravity of the valve core (and the spring force) to push the valve core to reset at a suitable speed. The spherical valve core tightly fits the sealing surface of the valve seat, forming an excellent seal to prevent the medium from flowing back, avoid water pump reversal, pipeline water hammer, or equipment damage.

Low flow sealing: The line contact sealing design between the spherical valve core and the valve seat can achieve excellent sealing effect through the small displacement of the valve core even under low flow or low pressure conditions, reducing medium leakage.

Core advantages of the product

Low resistance and energy-saving, flow effect: The streamlined valve body and spherical valve core design ensure that the valve core fully fits the flow channel when fully opened, without obvious obstruction. The fluid resistance is much lower than other types of check valves, which can reduce water pump energy consumption and improve pipeline transportation efficiency, especially suitable for high flow and high pressure pipeline systems.

Good sealing and no leakage: The spherical valve core is sealed in line contact with the valve seat (soft seal is surface contact), and the sealing surface is tightly fitted. The valve core has an automatic centering function, which can protect the sealing effect even if there is a slight deviation in installation, and the effect is excellent in preventing medium backflow.

Smooth opening and closing, noise reduction and anti hammering: The valve core moves smoothly, without any metal impact sound, and has low operating noise; When closed in reverse, the response speed is appropriate, which can effectively weaken the impact of water hammer and protect the safety of pipelines, pumps, and downstream equipment.

Compact structure, flexible installation: small in size and light in weight (only 1/3~1/2 of the same specification rotary check valve), can be installed horizontally, vertically, or diagonally (when installed vertically, the medium needs to move from bottom to top), adapts to different installation space requirements, and saves pipeline layout costs.

Stable and wear-resistant performance (based on actual reports), long service life: The valve body and valve core can be made of corrosion-resistant (based on actual reports) and wear-resistant (based on actual reports) materials such as stainless steel and ceramics, suitable for complex media such as sewage, seawater, and oil. The soft seal valve seat is made of aging rubber or PTFE, and the hard seal valve seat is hardened, with a service life of up to 8-15 years (under normal working conditions).

Easy maintenance, low cost: simple structure, few vulnerable parts (only the valve seat is the core vulnerable part), easy disassembly and replacement, no need for specialized tools; Daily operation does not require additional maintenance, reducing operation and maintenance costs.

Installation key points

Installation direction: It is necessary to confirm that the arrow direction on the valve body is consistent with the forward flow direction of the medium. Reverse installation is strictly prohibited, otherwise the check function cannot be achieved.

Installation position: Priority should be given to installing near the outlet of the water pump (≤ 2 meters away from the water pump) to avoid medium backflow causing the water pump to reverse; When installed horizontally, the valve core guide channel should be vertically upward, and when installed vertically, the medium should move smoothly from bottom to top.

Supporting equipment: Install gate valves or ball valves before and after the valve to facilitate cutting off the pipeline during maintenance; For pipelines with high impurities (such as sewage pipes and industrial waste pipes), a filter (with a filtration accuracy of ≤ 3mm) should be installed at the front end to prevent impurities from jamming the valve core and affecting the opening and closing function.

Installation gap: When connecting flanges, it is necessary to protect the sealing gasket from being installed in place, tighten the bolts evenly, and avoid deformation of the valve body; Temperature control is required during welding connections to prevent deformation of the valve core and seat due to heat.

Exhaust treatment: After installation, before operation, it is necessary to exhaust the air inside the valve to avoid air blockage affecting the movement of the valve core.