A backflow preventer adapted for installation in an inner conduit of a hose coupling of a hydrant is disclosed. The backflow preventer contains a non-return device having a closing body, a seal seat, and a resetting device. The resetting device is adapted to resiliently pretension the closing body into sealing engagement against the seal seat.

A check valve assembly includes a first flapper, a second flapper, an internal passage formed by the first flapper and the second flapper, and a nozzle disposed within the internal passage and configured to generate an internal flow in the internal passage. In response to a fluid flow through the check valve assembly, the first flapper and the second flapper are configured to move between an open position allowing the internal flow through the internal passage and an outer flow outside the internal passage, and a closed position preventing flow through the internal passage. When the first flapper and the second flapper are operably in the open position, the internal flow has a lower pressure than the outer flow outside of the internal passage, such that the first flapper and the second flapper are maintained in the open position.

The valve comprises a fluid inlet and/or outlet duct (8) comprising a flowrate regulator element (9) and a seating (10) for said fluid inlet and/or outlet duct (8), said seating (10) including a surface (10b) adapted to be attached to a portion of an internal bag (4) made of flexible material in the container (1), and is characterised in that it comprises a cover (11) to protect said seating (10) and comprising a hole for access to said fluid inlet and/or outlet duct (8); said cover (11) comprising means (13, 14) for securing a protective wrapping (5) enveloping the internal bag (4) on said seating (10). The container is characterised in that it includes at least one valve (3a, 3b) for the injection and/or extraction of fluid, and in that a portion of said internal bag (4) made of flexible material is attached to the seating (10) of the inlet duct (8) of said valve (3a, 3b) and that a portion of the protective wrapping (5) for said internal bag (4) is held against said seating (10) by the cover (11).

This invention relates to a release valve (100) for fire protection systems, consisting of a tubular body (1) with a first end and a second end, and which comprises: coupling means with an extinguishing gas source at a first pressure, arranged at said first end; an outlet (12), arranged at said second end; a pressurisation inlet (11), arranged in a position between said coupling means and said outlet (12) and able to be connected to pressurising means at a second pressure, greater than said first pressure; a rupture disc (2), arranged in a position between said pressurisation inlet (11) and said outlet (12) and configured to open at said second pressure; and a non-return device (3), arranged in a position between said coupling means and said pressurisation inlet (11), said non-return device (3) being configured to allow a passage of fluid in the direction from said coupling means towards said pressurisation inlet (11) and prevent a passage of fluid in the direction from said pressurisation inlet (11) towards said coupling means.

The invention also relates to a fire protection system comprising an extinguishing gas source connected to a release valve (100) for fire protection systems of the above type and a method for activating said system.

A check valve assembly includes a first flapper, a second flapper, an internal passage formed by the first flapper and the second flapper, and a nozzle disposed within the internal passage and configured to generate an internal flow in the internal passage. In response to a fluid flow through the check valve assembly, the first flapper and the second flapper are configured to move between an open position allowing the internal flow through the internal passage and an outer flow outside the internal passage, and a closed position preventing flow through the internal passage. When the first flapper and the second flapper are operably in the open position, the internal flow has a lower pressure than the outer flow outside of the internal passage, such that the first flapper and the second flapper are maintained in the open position.

A check valve includes a valve body defining a valve bore extending from a first axial end to a second axial end, the valve body including an annular body and a cross member secured to and extending across the valve bore from the annular body on one side of the valve body to the annular body on an opposite side of the valve body, the valve bore at the cross member divided into more than one portion by the cross member; a position block extending from the cross member; a valve member positioned within the valve body and configured to rotate between an open position and a closed position; and a pivot pin extending from the valve member, engaged with the position block, and fixed with respect to the valve member; the valve member and the pivot pin configured to rotate together between the open position and the closed position.

A hydrant includes: a hydrant body defining a hydrant inner cavity, the hydrant configured to couple to and be in fluid communication with a fluid distribution system including a fluid therein under pressure; and a break check valve coupled to the hydrant body, the valve including: a valve body defining a valve inner cavity, the hydrant inner cavity defining a valve bore in fluid communication with the fluid during normal operation of the hydrant; a valve member configured to rotate from an open position to a closed position of the valve; and an arm in contact with the hydrant and configured to prevent movement of the valve member when the hydrant is coupled to the valve, the valve defining a hole separate from the valve bore and in fluid communication with each of the hydrant inner cavity and the valve inner cavity.

A check valve has a valve housing defining a first valve opening and a second valve opening. A first flapper is pivotably mounted around a first axis for rotation relative to the housing between an open position at which it permits fluid flow through the first valve opening and a closed position at which it prevents fluid flow through the first valve opening. A second flapper is pivotably mounted around a second axis for rotation relative to the housing between an open position at which it permits fluid flow through the second valve opening and a closed position at which it prevents fluid flow through the second valve opening. The first axis is spaced laterally from the second axis. A method is also disclosed.

A check valve can include a valve body defining a valve bore, the valve body comprising an annular body and a cross member secured to and extending in a radial direction across the valve bore from the annular body on one side of the valve body to the annular body on an opposite side of the valve body, the valve bore at the cross member divided into more than one portion by the cross member; a position block extending from the cross member; a pair of valve members, each valve member of the pair of valve members positioned within the valve body and configured to rotate between open and closed positions; and a pivot pin positioned within the valve body and extending through the position block and each valve member of the pair of valve members, the pivot pin being supported only by the position block.

A check valve for a fluid distribution system can include a valve body defining a valve inner cavity defining a valve bore extending from a first axial end to a second axial end; a position block secured to the valve body and defining a pivot bore; a pivot pin positioned within the valve body and extending through the pivot bore of the position block; and a valve member positioned within the valve body and configured to rotate about the pivot pin from an open position to a closed position, the valve member configured to remain in the open position as long as a fluid in the fluid distribution system is moving in a positive flow direction of the check valve, the valve member further configured to close when the fluid is moving in a negative flow direction of the check valve.