KF40CV80 is a vacuum check valve for vertical installation only, using an internal ball and the principle of gravity. With a CF8M (316) body and FKM (Viton) seal combination, it offers an operating temperature of -5 to 100°C, a leak rate of 1×10⁻⁸ mbar·L/s, and a minimum opening differential pressure of approximately 7 mbar, and is used for backflow prevention in vertical lines of vacuum systems in semiconductor, display, solar, and laboratory applications.
Features
Designed to prevent backflow in air, inert gas, and vacuum environments
Maintains vacuum protection - usable in low-pressure piping conditions
Internal ball operates by gravity - vertical installation only
Specifications
Size
KF-40
FLANGE
KF(NW)
Material
BODY: CF8M(316) / SEAL: FKM
TEMP RATE
-5°C-100°C
LEAK RATE
1x10⁻⁸ mBARL/SEC
PRESSURE RANGE
1x10⁻⁵ mBAR
RELIEF MINIMUM PRESSURE△P
7mBAR
PUMPING SPEED
10000(L/MIN)
INSTALLATION POSITION
ANY
Frequently Asked Questions
Why is it limited to vertical installation?
KF40CV80 has a structure where the internal ball is automatically seated by gravity. Vertical installation is essential because the direction of gravity must align with the check direction so that the ball can move into position and block the line when backflow occurs. If horizontal or arbitrary-direction installation is required, choose the spring-loaded KF40CV80S variant.
What is the difference between KF40CV80 and KF40CV80S?
KF40CV80 is a gravity-operated ball type, vertical-only installation, with a simple structure and price advantage. KF40CV80S is spring-loaded and can be installed in any direction (vertical or horizontal), offering greater freedom in piping layout. Choose KF40CV80 for sections fixed as vertical, and KF40CV80S for sections requiring free installation orientation.
What happens if the operating temperature range is exceeded?
The standard specification supports the -5 to 100°C range. In high-temperature environments exceeding this range, the FKM (Viton) seal can harden and lose elasticity, reducing sealing performance, so heat-resistant seal materials or metal-sealing structures must be considered for high-temperature lines.
How much does it affect pumping speed?
KF40CV80 is designed for use even in large-volume pumping lines around 10,000 L/min, and because the minimum opening differential pressure is as low as approximately 7 mbar, its impact on pumping speed under normal operation is limited.