Alfa Laval 45BYMP Y-Body Ball Check Valve

Central States Industrial (CSI) offers the original sanitary Y-body check valve—Alfa Laval's 45BYMP ball check valve. This valve provides backflow prevention for stainless steel process lines. Its simple, robust design delivers years of reliable service.

With a sanitary design and low pressure drop, the 45BYMP has been a trusted option for years. The valve meets 3-A sanitary standards and can be mounted either vertically or horizontally.

45BYMP is authorized to carry the 3-A symbol.


The 45BYMP ball check valve operates at a wide range of pressures and flow rates. Because the sealing check ball moves completely out of the process flow when open, the valve offer low pressure reduction and handles viscous liquids or liquids containing solid particles easily. Alfa Laval's 45BYMP is authorized to carry the 3-A symbol.


When liquid under normal pressure enters the inlet of the 45BYMP check valve, an elastomeric ball is pushed upward into the "Y" branch (lower pressure area) of the valve. When the liquid flow stops, the pressure within the valve equalizes, and the ball returns from the "Y" branch of the valve and rests itself against the smaller diameter of the valve near its inlet. Should a reverse flow situation occur, the opposing pressure of the fluid will seat the ball firmly against the inlet of the valve, preventing reverse flow. The valve operates in both a vertical or horizontal orientation.


The valve consists of a single-piece, stainless steel body with an elastomeric ball (see materials table for options). The "Y" branch of the valve maintains a Tri-Clamp® connection along with an associated Tri-Clamp, end-cap, and NBR gasket. The valve is polished internally and externally to meet or exceed 3-A sanitary standards.

Product Wetted Steel Parts316L
Other Steel Parts304
BallBuna, EPDM, SFY, Nylon (max 140°F)
GasketNBR (standard)
Finish32 Ra (standard)
Size1 1/2 – 3 inch
ConnectionsTri-Clamp, weld
Max Product Pressure200 psi
Min Product Pressure1 psi
Temperature RangeBased on elastomer choice
Tube OD




Approx. Weight


1 1/28 19/323.00
210 3/323.25
2 1/211½7.69
45BY-Size-02-Ball, Replacement Balls
Tube OD




1 1/21 5/8
22 1/8
2 1/23 1/2
34 1/8
Pressure Drop Curves

All curves are tested pressure drop curves, not certified, and should be applied for guideline purposes only. Performance curves are based on tests using 68°F water.

Spare Parts

45BYMP Y-Body Ball Check Spare Parts
Buna Ball621934623203624209625150
EPDM Ball620374620376620996620995
SFY Ball


Nylon Ball620995620998620999621000
Air Check Valve, EPDM830045830048830099830100
Air Check Valve, SFY830138


Gasket, Buna298453298454298456298577
Gasket, EPDM290043290048290018290147
Gasket, SFY290030290040290053290060
Back Up Gasket, Buna220191220191220191220191
Back Up Gasket, EPDM220275220275220275220275

Back Up Gasket, SFY

"A" Adapter763278763278763278763278
"B" Adapter213384213384213384213384
"C" Adapter (3/8")210339210339210339210339
"C1" Adapter (1/2")214206214206214206214206
"C2" Adapter (3/4")211677211677211677211677

45BYMP Y-Body Ball Check Valve Parts List

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