A coupling unit for a fluid element includes a monolithic body having a head and a threaded portion extending from the head, the threaded portion including a core and a thread formed on the core. The monolithic body defines a first bore and a second bore that extend through the monolithic body substantially parallel to each other, the first and second bores each having a circular cross-section.

A check valve supplies fluid to a system and includes a fluid barrier protects the sealing elements and surfaces of the check valve preventing degradation from any backflow of gas and debris from the system to which fluid is supplied.

A double-membrane pump has a pump housing and at least a first electromagnet associated with the pump housing. Magnet action elements that are ferromagnetic or permanent-magnetic elements or at least a second electromagnet associated with first and second membranes are alternately attracted or repelled by the first electromagnet, in contact-free manner. The ferromagnetic or permanent-magnetic elements may be metal bodies connected with the membranes or flexible metal layers associated with the membranes. The first-electromagnet may have first and second magnetic coils that can be operated independently of one another and that can influence the first and second membranes independently of one another.

A check valve supplies fluid to a system and includes a fluid barrier protects the sealing elements and surfaces of the check valve preventing degradation from any backflow of gas and debris from the system to which fluid is supplied.

A check valve supplies fluid to a system and includes a fluid barrier protects the sealing elements and surfaces of the check valve preventing degradation from any backflow of gas and debris from the system to which fluid is supplied.

A double-membrane pump has a pump housing and at least a first electromagnet associated with the pump housing. Magnet action elements that are ferromagnetic or permanent-magnetic elements or at least a second electromagnet associated with first and second membranes are alternately attracted or repelled by the first electromagnet, in contact-free manner. The ferromagnetic or permanent-magnetic elements may be metal bodies connected with the membranes or flexible metal layers associated with the membranes. The first-electromagnet may have first and second magnetic coils that can be operated independently of one another and that can influence the first and second membranes independently of one another.

A diaphragm pump can include an inlet, an outlet, and a pump chamber positioned in a fluid path between the inlet and outlet. The assembly can include a diaphragm and a movable piston. Movement of the piston toward the pump chamber can force a portion of the diaphragm to move from its rest position to a position further within the pump chamber and to increase pressure in the pump chamber. Movement of the piston away from the pump chamber can force a portion of the diaphragm to move from its rest position to a position away from the pump chamber and to reduce pressure in the pump chamber. The assembly can also include a first and second check valve. In the closed position, the second check valve can be unsealed to provide an escape path for gas. In the closed position, the first check valve can be sealed.

A coupling unit for a fluid element includes a monolithic body having a head and a threaded portion extending from the head, the threaded portion including a core and a thread formed on the core. The monolithic body defines a first bore and a second bore that extend through the monolithic body substantially parallel to each other, the first and second bores each having a circular cross-section.

A check valve supplies fluid to a system and includes a fluid barrier protects the sealing elements and surfaces of the check valve preventing degradation from any backflow of gas and debris from the system to which fluid is supplied.

A check valve supplies fluid to a system and includes a fluid barrier protects the sealing elements and surfaces of the check valve preventing degradation from any backflow of gas and debris from the system to which fluid is supplied.