Pressure flush tank for toilets

In a pressure flush tank system in which a water tank has a water inlet, a water outlet, a control cylinder vertically oriented above the water outlet, a main valve seat in the water outlet, a main flush valve in the cylinder adapted to seat on said main valve seat and having a central valve bore, and a manual control valve operable in said central valve bore to open said control valve bore and thereby relieve pressure in the cylinder above the main flush valve, said main valve being movable in said cylinder in a slidable piston relationship and subject to pressure of said tank whereby opening the central bore will cause upward movement of said main valve in said cylinder and opening of said main valve seat, that improvement which comprises:

• (a) means resiliently biasing said main flush valve to a partially open position wherein pressure in said cylinder will cause full closing of said main valve, and loss of water inlet pressure in said tank will effect opening of said main valve to allow water to drain from said tank through said main valve seat thus removing it from the water inlet to prevent backflow in the event of below atmospheric pressure in said water inlet, and
• (b) a secondary valve opening communicating between the interior of said tank and said water outlet, a refill valve in said secondary valve opening to close the secondary opening in response to pressure in said tank, and means to bias said refill valve to an open position and responsive to a predetermined pressure in said tank to close the refill valve.

In a pressure flush tank system in which a water tank has a water inlet, a water outlet, a control cylinder vertically oriented above the water outlet, a main valve seat in the water outlet, a main flush valve in the cylinder adapted to seat on said main valve seat and having a central valve bore and a manual control valve operable in said central valve bore to open said control valve bore and thereby relieve pressure in the cylinder above the main flush valve, said main valve being movable in said cylinder in a slidable piston relationship and subject to pressure of said tank whereby opening the central bore will cause upward movement of said main valve in said cylinder and opening of said main valve seat, that improvement which comprises:

• (a) a refill system including a resiliently biased, pressure responsive time-delay valve communicating between the interior of the tank and the outlet responsive to pressure in said tank to control the quantity of water entering the bowl after the siphonic flush action,
• (b) a flow restrictor valve in said water inlet to control the flow rate of water into said tank, and
• (c) said refill system comprising a secondary valve opening communicating between the interior of said tank and said water outlet, said time delay valve being located in said secondary opening to close the opening in response to predetermined pressure in said tank, and means to bias said time delay valve to an open position and responsive to a predetermined pressure in said tank to close the time-delay valve.

In a pressure flush tank system in which a water tank has a water inlet, a water outlet, a control cylinder vertically oriented above the water outlet, a main valve seat in the water outlet, a main flush valve in the cylinder adapted to seat on said main valve seat and having a central valve bore and a manual control valve operable in said central valve bore to open said control valve bore and thereby relieve pressure in the cylinder above the main flush valve, said main valve being movable in said cylinder in a slidable piston relationship and subject to pressure of said tank whereby opening the central bore will cause upward movement of said main valve in said cylinder and opening of said main valve seat, that improvement which comprises:

• (a) a refill system communicating between the interior of the tank and the outlet responsive to pressure in said tank to control the quantity of water entering the bowl after the siphonic flush action,
• (b) a flow restrictor valve in said water inlet to control the flow rate of water into said tank, and
• (c) said refill system comprising means forming an opening in a wall of the main flush valve open to the interior of the tank, a refill valve in said opening to close the opening, and means carried by said valve to bias said refill valve to an open position responsive to a predetermined pressure in said tank to close the refill valve against said bias means.

In a pressure flush tank system in which a water tank has a water inlet, a water outlet, a control cylinder vertically oriented above the water outlet, a main valve seat in the water outlet, a main flush valve in the cylinder adapted to seat on said main valve seat and having a central valve bore, and a manual control valve operable in said central valve bore to open said central valve and thereby relieve pressure in the cylinder above the main flush valve, said main valve being movable in said cylinder in a slidable piston relationship and subject to pressure of said tank whereby opening the central bore will cause upward movement of said main valve in said cylinder and opening of said main valve seat, that improvement which comprises:

• (a) means resiliently biasing said main flush valve to a partially open position wherein pressure in said cylinder will cause full closing of said main valve, and loss of water inlet pressure in said tank will effect opening of said main valve to allow water to drain from said tank through said main valve seat thus removing it from the water inlet to prevent backflow in the event of below atmospheric pressure in said water inlet,
• (b) a secondary valve opening communicating between the interior of said tank and said water outlet, a refill valve in said secondary valve opening to close the secondary opening in response to pressure in said tank, and means to bias said refill valve to an open position and responsive to a predetermined pressure in said tank to close the refill valve,
• (c) an inlet flow director tube in the tank connected to the water inlet and having an outlet adjacent the top of the tank above the water level wherein only air can backflow in the event of negative water pressure, and
• (d) an air vent in the water inlet of the water tank open to the top portion of the tank, a biased valve normally closing said air vent and movable against said bias to open said vent and having a portion exposed to said water inlet, said valve being movable in response to reduced pressure induced by flow into said water tank through said water inlet and by negative pressure in said water inlet to admit air through said air vent opening to said tank.