Pressure-activated trap primer valve

Abstract

A pressure activated trap primer valve for drain traps includes an expansion chamber with a piston between the compressible air and water. The piston prevents waterlogging of the expansion chamber to reduce maintenance of the trap primer valve. The trap primer valve also includes an inlet pipe coaxially configured in the expansion chamber. The inlet pipe is operably connected to a chamber below the expansion chamber which is closed at the bottom by a diaphragm. The diaphragm in a relaxed, undeflected position closes an outlet that drains to the trap. A chamber below the diaphragm is replenished by the expansion chamber. When pressure in the supply pipe and inlet pipe decreases, such as when a faucet is opened, the diaphragm deflects. Deflecting the diaphragm opens the outlet, allowing a limited amount of water to flow out of the chamber and into the trap. The intermittent water flow to the trap ensures a minimum volume for maintaining a gas tight seal in the trap. As trap primer valve pressures reach equilibrium, the diaphragm returns to an undeflected position, sealing the outlet again.

Description

BACKGROUND

The present invention relates to plumbing systems and components and more particularly, to trap primer valves which supply a minimal flow of water to keep drain traps from drying out. Drain traps are configured to retain water which prevents sewer line gases from rising through the sewer lines and into buildings. Sewer gases are not only offensive, but concentrated in a closed space with an ignition source, they can explode. Drain traps keep noxious gases from occupied areas and prevent the possibility of explosion.

In homes and buildings, traps are generally located below and close to each drain, and generally have a U-shaped configuration with an inlet on one arm and an outlet on the other arm, the outlet being lower than the inlet. The bottom of the ‘U’ is filled with water to the level of the outlet and seals the trap. In situations where the drain only gets intermittent use, the trap water can evaporate, allowing gases to flow up the drain pipe and into buildings. The trap primer valve introduces intermittent water flows, maintaining a seal regardless of how often it is used and ensures the trap continues to function.

There are a variety of trap primer valves available, some have processors and electronic valves that determine time and duration of flow to the traps. Some trap primer valves have a diaphragm or piston acting as a valve component, so that when there is a drop in line pressure, the diaphragm or piston is displaced, permitting a limited flow of water. These primers often use an expansion chamber to provide a pressure differential across the diaphragm or piston and supply the water for the flow.

The expansion chambers of trap primer valves with this configuration have the opposite problem of the drain trap. The air above the water in the expansion chamber can be slowly absorbed by the water. Absorbing all the air in the expansion chamber is known as “waterlogging.” The expansion chamber works by increasing or decreasing the volume of a closed air chamber, compressing and decompressing the air in response to variations in line pressure. With no air in the chamber, the primer can't function properly, and once a trap primer valve becomes waterlogged, it has to be repaired by removing it from the supply line, draining it and returning it to service.

There is a need for a vacuum-operated trap primer valve to supply drain traps with water that does not become waterlogged and accordingly does not require maintenance to recharge the expansion chamber.

SUMMARY OF THE INVENTION

The present invention is directed to a trap primer valve including a valve housing and piston slidably supported in the housing and sealed therewithin to provide separable air and water chambers. This construction prevents air in the air chamber from being absorbed by the water which; over time, would fill the air chamber.

The exemplary trap primer valve of the present invention is activated by variation in pressure in the supply line to which it is attached. The trap primer valve includes a housing with an inlet that attaches to a supply line and an outlet that runs to a trap. The housing is divided into upper and lower sections by a plate. The upper section is an expansion chamber with trapped air and water.

The inlet pipe runs vertically through the upper section expansion chamber and is operably connected to the lower section. The air and water in the upper section expansion chamber are separated by a piston which is tightly sealed against the housing walls and the inlet pipe. The piston slides vertically in response to changes in water pressure maintaining equal pressure in the water below the piston and the air above the piston.

The lower section of the valve is separated into upper and lower chambers by a diaphragm. The upper chamber is connected to the supply line by the inlet pipe that passes through the upper section, and is maintained at the same pressure as the inlet pipe and supply line. The upper chamber of the lower section is connected to the expansion chamber by a check valve in the dividing plate that allows water to flow from the upper chamber into the expansion chamber.

The lower chamber is defined by the diaphragm and a base directly below the diaphragm. The diaphragm is operably connected to the outlet formed in the base. The outlet is open or shut depending on whether the diaphragm is deflected or undeflected, respectively. The lower chamber is supplied with water from the expansion chamber by channels formed in the rim of the base.

The outlet is open only when the inlet pipe pressure drops. As the inlet pressure drops, the pressure in the chamber above the diaphragm drops and the check valve in the plate between the expansion chamber and upper chamber closes because the air in the expansion chamber is still at the higher pressure. Water cannot flow from the expansion chamber into the upper chamber with the valve closed.

The pressure drop in the chamber above the diaphragm causes the diaphragm to deflect or rise due to the pressure differential above and below the diaphragm. Deflecting the diaphragm opens the outlet and allows water to flow out from the lower chamber and downwardly into the outlet pipe. As water flows out of the chamber below the diaphragm, the pressure drops, the diaphragm returns to the undeflected position as the pressure differential equalizes, again closing the outlet.

Water does flow from the expansion chamber, through the channels, to the lower chamber below the diaphragm to recharge the water lost to the outlet. Without air in the expansion chamber, low pressure in the supply line would close the check valve and a vacuum would form as water tried to flow out of the expansion chamber and the outlet.

The advantages of the present invention will be understood more readily after a consideration of the drawings and the Detailed Description of the Preferred Embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a plumbing system using a drain trap primer valve of the present invention showing a supply line extending through a wall, with an attached faucet at the end of the supply line, a primer valve is shown attached to the supply line, a drain trap on the other side of the wall and a line connecting the primer valve to the drain trap.

FIG. 2 is a cross sectional side view of the trap primer valve of the present invention with its diaphragm in an undeflected position thereby closing the outlet, including a piston, a plate, a diaphragm and a base.

FIG. 3 is a cross sectional side view of the lower section of the trap primer valve of FIG. 2 showing the diaphragm in a deflected position thereby opening the outlet.

FIG. 4 is a top view of the base of FIG. 4 showing the channels along the top rim of the base.

FIG. 5 is a schematic view of a primer valve system similar to FIG. 1 showing a faucet and the trap primer valve attached to a supply line, the trap primer valve including an inlet pipe, a diaphragm, a check valve, a piston and chambers.

FIG. 6 is a schematic view of the trap primer valve system of FIG. 5 in equilibrium.

FIG. 7 is a schematic view of the trap primer valve system of FIG. 5 during a drop in supply line pressure which causes the diaphragm to deflect thereby, allowing flow from the outlet and water flowing to the lower chamber from the upper section, displacing the piston downwards.

FIG. 8 is a schematic view of the trap primer valve system of FIG. 5 showing line pressure returning to normal and water flowing to the upper section displacing the piston upwards.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows the arrangement of a supply and drain system, generally indicated at 10, including a supply pipe or supply line 12, a faucet 14, a primer drain 16, a trap 18 and the location of a trap primer valve 20 constructed in accordance with the present invention. Trap 18 is connected to drain D in floor F and supply pipe 12 supplies water or water under pressure to faucet 14 which can be opened or closed by a user. Trap primer valve 20 is operable to meter or supply small volumes of water through primer drain 16 to trap 18, thereby to maintain water continuously in the trap. Trap primer valve 20 functions as a valve controlled by fluctuations in supply pipe pressure, as will be described.

As shown in FIG. 2, trap primer valve 20 includes a housing 22, which includes a conical section 23a and a cylindrical section 23b, an inlet pipe 24, an inlet connector 26, a slideable piston 27 including an inner circumference defined by a sleeve 28 and an outer circumference indicated at 29. A plate is shown at 30, a diaphragm at 32 and a base at 34. Housing 22, including conical portion 23a and cylindrical section 23b, along with inlet pipe 24, forms inner and outer coaxial tubes. The interior diameter of section 23b is constant, so that piston 27 can slide up and down without binding. Plate 30 and base 34 are fixed in housing 22 and retain diaphragm 32 between them. Diaphragm 32 is shown in FIG. 2 in a relaxed or undeflected position. Base 34 includes a drain pipe 36 and an outlet 37. The wall of drain pipe 36 may have ports or perforations 38 to prevent a vacuum in drain pipe 36.

Piston 27 with inside circumference 28 and outside circumference 29 form an annular ring or disk. Inside circumference 28 forms a sleeve that holds an inner seal or O-ring 39, compressed to form a seal between inlet pipe 24 and the inner circumference of piston 27. Outer circumference 29 holds an outer seal or O-ring 40 which is compressed to form a seal between outer circumference 29 and the inner wall of cylindrical section 23b. Piston 27 with O-rings 39 and 40 prevent air from being absorbed in the water below piston 27. If water were permitted to be absorbed, trap primer valve 20 eventually could fail.

Base 34 and diaphragm 32 define a lower chamber 100 and an upper chamber 200 above the diaphragm. Housing 22, inlet pipe 24, piston 27 and plate 30 define a water chamber 300. An air chamber 400 above piston 27 is defined by housing 22, inlet pipe 24 and piston 27. Expansion chamber 500 includes water chamber 300, air chamber 400 and piston 27.

Plate 30 separates expansion chamber 500 from the lower section which includes chambers 100 and 200 and diaphragm 32. Plate 30 includes a first stepped hole 46 to accommodate the end of pipe 24. Plate 30 includes a second stepped hole 48 which forms valve 50. Valve 50 may be a ball check valve with means to retain the ball in the valve housing (not shown).

Plate 30 is retained in position in housing 22 by a step or shoulder 52. Plate 30 is sized to provide water flow between housing 22 and plate 30 so water may flow from chamber 300 to channels 44 in base 34. Shoulder 52 is configured to allow water flow around plate 30.

The upper surface of piston 27 faces air chamber 400 and its bottom surface faces water chamber 300. As such, piston 27 slides up and down in response to pressure differentials between water chamber 300 and air chamber 400. Piston 27, plate 30, and base 34 may be manufactured from any appropriate material such as nylon, ABS or a metal such as copper or a copper alloy. Housing 22 may also be manufactured from copper or a copper alloy.

Diaphragm 32 may be a disk manufactured from an appropriate material such that it will flex appropriately under pressure. Diaphragm 32 may vary in thickness from the center to the rim. It may have a thickened rim. Diaphragm 32 may be thicker at the center than towards the rim.

Diaphragm 32 deflects when the pressure in chamber 200 drops below the pressure of chamber 100. FIG. 3 is a cross section of the lower part of trap primer valve 20 showing diaphragm 32 in a deflected position caused by a reduction in pressure in chamber 200. Deflection of diaphragm 32 uncovers outlet 37 allowing water to flow out from chamber 100. Air pressure in the chamber 400 urges piston 27 downwardly to force water in chamber 300 through channels 44 into chamber 100 and outwardly through outlet 37.

FIG. 4 is a top view of base 34 showing channels 44 along the rim of base 34. Base 34 includes drain pipe 36 and outlet 37. Base 34 has channels 44 in the upper rim. Channels 44 permit water from chamber 300, passing between plate 30 and housing 22, to enter chamber 100.

When plate 30, diaphragm 32 and base 34 are assembled, diaphragm 32 is compressed and is sealed against plate 30. Water is prevented from flowing from chamber 200 to chamber 100 by diaphragm 32. Water may flow from chamber 300 above plate 30, between plate 30 and housing 22 and through channels 44 into chamber 100. Channels 44 may limit the rate of flow rate into chamber 100.

Operation of the Trap Primer Valve

The operation of the trap primer valve of the present invention is illustrated in the schematic view of FIGS. 5-8. FIG. 5 shows a supply system 60, similar to supply system 10 in FIG. 1, illustrating the operation of trap primer valve 20. Shown in the schematic illustration are supply line 12, faucet 14, trap 18 in floor F below drain D. Trap primer valve 20 is operably connected to supply line 12 and connected to drain trap 18 by drain pipe 36. Inlet pipe 24 operably connects supply line 12 to chamber 200. Chamber 200 includes diaphragm 32, outlet 37 and valve 50.

Normal pressure in the following figures is the pressure in supply line 12 with faucet 14 closed. Opening faucet 14 decreases pressure in supply line 12. FIG. 6 shows supply system 60, at equilibrium with supply pipe 12 and chamber 200 at normal pressure. Diaphragm 32 is undeflected and closes outlet 37. Chambers 100, 300 and 400 are also at normal pressure, which is the pressure of supply line 12.

FIG. 7 shows primer system 60 as faucet 14 is opened by a user. The pressure in supply line 12 drops as faucet 14 is opened. Pressure also drops in chamber 200, operably connected to supply pipe 12, valve 50 closes and diaphragm 32 deflects upwardly with the reduced pressure in chamber 200. With diaphragm 32 deflected, outlet 37 is uncovered and water from chamber 100 flows from outlet 37 to trap 18.

Flow from outlet 37 is enabled by air pressure in chamber 400. Chamber 400 air pressure displaces piston 27 pushing on water in chamber 300 and causing water flow around chamber 200 and into chamber 100. Without the air compressed in chamber 400, no flow would occur out of outlet 37.

FIG. 7 shows supply system 60 as faucet 14 is closed and pressure in supply line 12 returns to normal. The pressure in chamber 200 returns to normal as well. Diaphragm 32 returns to its normal, undeflected position closing outlet 37. Because pressure in chamber 200 is now greater than chambers 300 and 100, water flows from chamber 200 to chamber 300 through valve 50. As chamber 300 pressure increases, piston 27 rises and compresses air in chamber 400.

Trap primer valve 20 returns to equilibrium again with chambers 100, 200, 300 and 400 at the same pressure as supply line 12 and outlet 37 closed as represented in FIG. 8. As pressure drops again, the process will be repeated.

Water is relatively incompressible and cannot store adequate pressure energy to function in this configuration. Functioning of expansion chamber 500 prevents vapor lock and siphoning in trap primer valve 20. Expansion chamber 500 allows the pressure energy to be stored as air pressure in chamber 400 and released when it is required.

Outlet 37 may be configured with vacuum breaker port 38. Vacuum breaker port 38 ensures that water from trap 18 cannot be pulled into trap primer valve 20 and contaminate the water supply. Any water coming back up primer drain 16 of FIG. 1 will flow out vacuum port 38 rather than up outlet 37, which is of limited diameter.

These are examples and should not be construed as limitations. Any configuration or combination of components presented which performs a similar function should be considered as within the scope of this disclosure.

It is believed that the disclosure set forth above encompasses multiple distinct inventions with independent utility. While each of these inventions has been disclosed in its preferred form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the inventions includes all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/or properties disclosed herein. Similarly, where any claim recites “a” or “a first” element or the equivalent thereof, such claim should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements.

Inventions embodied in various combinations and subcombinations of features, functions, elements, and/or properties may be claimed through presentation of new claims in a related application. Such new claims, whether they are directed to a different invention or directed to the same invention, whether different, broader, narrower or equal in scope to the original claims, are also regarded as included within the subject matter of the inventions of the present disclosure.

Claims

1. A trap primer comprising

a first section separated into an upper air chamber and a lower water chamber by a sliding piston configured to prevent air leaving the upper air chamber;

a second section, below the first section, the second section divided into an upper chamber and a lower chamber by a diaphragm;

an inflow pipe through the center of the first section to the upper chamber of the second section; and

an outlet from the second section lower chamber with flow from the outlet controlled by the diaphragm;

wherein the upper chamber of the second section is connected to the first section by a check valve;

the lower chamber of the second section is supplied with water from the first section; and

a drop in pressure at the inflow pipe raises the diaphragm, releasing water from the outlet.

2. The trap primer of claim 1 where the sliding piston is sealed at inner and outer circumferences by o-rings.

3. The trap primer of claim 1 where the check valve has a ball and a seat.

4. An expansion chamber to be used in a trap primer valve, the expansion chamber comprising:

a first inner coaxial tube configured to connect to a water supply line;

a second outer coaxial tube which acts as a housing;

a first, upper end of the expansion chamber, the upper end closed by joining the inner and outer tube;

a second, lower end of the expansion chamber defined by a piston slidable between the inner and outer tube;

wherein the expansion chamber is charged with a gas that acts on a first upper side of the piston;

water pressure in the supply line acts on a second lower side of the piston;

the piston is sealed to the inner and outer coaxial tubes; and

displacing the piston changes the volume of the gas in the expansion chamber.

5. The expansion chamber of claim 4 where the piston is sealed by o-rings at the inner and outer circumferences of the piston.

6. The expansion chamber of claim 4 where the expansion chamber is part of a primer valve that operates as a function of changes in line pressure.

7. The expansion chamber of claim 4 where the first and second coaxial tubes are composed of copper or copper alloy.

8. The expansion chamber of claim 4 where the piston is composed of polyvinylchloride.

9. A piston to be used in a closed expansion chamber including a water supply pipe comprising;

an annular disk with a first inner circumference and a second outer circumference;

a seal located at the first circumference that contacts the supply pipe; and

a seal located at the second circumference that contacts an expansion chamber wall;

wherein the piston divides the expansion chamber into a closed upper gas filled section and a lower water filled section; and

differences in pressure between the upper filled gas section and the lower water filled section displaces the piston.

10. The piston of claim 9 where the seals are o-rings.

11. The piston of claim 9 where the annular disk is formed from polyvinylchloride.