GB2459536A

GB2459536A - Valve with float

Info

Publication number: GB2459536A
Application number: GB0807941A
Authority: GB
Inventors: Jeffrey Hamlett
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-05-01
Filing date: 2008-05-01
Publication date: 2009-11-04
Anticipated expiration: 2028-05-01
Also published as: GB0807941D0; GB2459536B

Abstract

A valve for closing the condensate drain outlet of a ventilating or air conditioning unit comprises a valve body 10 having first and second liquid flow ducts 12, 13 in fluid communication with a float chamber 15 disposed inside the valve body. A float 18 is disposed inside the chamber 15 for closing a valve orifice 17 which connects the first duct 12 to the chamber 15, the float 18 being arranged to remain seated across the valve orifice 17 until the first or second duct 12, 13 has completely filled with liquid. The float 17 only lifts to allow water to flow from the first duct 12 to the second duct 13 when the first duct 12 completely fills with water. Thus no reverse flow of air can pass along the drain outlet due to the fact that the valve orifice 17 is either closed or the first duct 12 is full of water.

Description

LIQUID FLOW VALVE

This invention relates to a liquid flow valve and more particularly but not solely to a liquid flow valve for closing the condensate drain outlet of an air handling unit.

Air handling units are provided in air-conditioning and ventilating systems to create a flow of air through vent ducting. Such air handling units comprise a cooling device or a so-called chiller which cools the air on demand. In use, moisture carried by the warm air, which is being chilled, condenses on the chiller and on other cold surfaces inside the air handling unit to create condensate water droplets: this condensate can drip inside the air handling unit and needs to be collected and drained. Typically, this is achieved by running a drain pipe from a tray disposed inside the housing of the air handling unit to an external outlet.

A disadvantage of the above-mentioned arrangement is that the fan inside the air handling unit creates a negative pressure inside the housing, which draws a flow of air into the air handling unit along the drain pipe. This external air can contain micro-organisms in a harmful matter which can undesirably contaminate the air flow through the air handling unit.

In order to overcome the above-mentioned problem, it is well known to provide a U-shaped trap in the condensate drain pipe, in order to prevent the reverse flow of air into the air handling unit. A disadvantage of this arrangement is that the trap needs to be full of water in order to block the flow of air. Accordingly, the trap needs to be checked regularly and topped up with water if necessary. However, it will be appreciated that traps are not always checked and thus there is a risk that the trap will not work effectively. Another disadvantage of U-shaped traps is that many air handling units are mounted close to the floor, with the result that the condensate drain pipe has to run across the floor with very little fall for the flow of water. The limited fall makes it difficult to mount a U-shaped trap.

US69331882 discloses a liquid flow valve for fitting to the condensate outlet pipe of an air handling unit, the valve comprising a valve body and first and second liquid flow ducts in fluid communication with a valve chamber disposed inside the valve body, and a float ball disposed inside the chamber for closing a valve orifice which connects the first duct to the chamber.

In use, the float ball normally closes the valve orifice to prevent the reverse flow of air from the second duct to first duct. However, when the first ducts starts to fill with water, the float ball floats and opens the valve orifice to allow the water to flow from the first and second ducts.

The valve orifice is oval in shape and is inclined across the end wall of the first duct.

Accordingly, the float ball starts to float as soon as the first duct begins to fill with water. A disadvantage of this arrangement is that the float ball allows air to flow from the second to the first ducts as soon as it starts to float and thus the risk of contamination is not fully avoided.

I have now devised a liquid flow valve which alleviates the above-mentioned problems.

In accordance with the present invention, there is provided a liquid flow valve comprising a valve body having first and second liquid flow ducts in fluid communication with a float chamber disposed inside the valve body, and a float member disposed inside the chamber for closing a valve orifice which connects said first duct to said chamber, wherein the valve member is arranged to remain seated across the valve orifice until the first or second duct has completely filled with liquid.

In use, the first duct is connected to the condensate drain outlet of a negative pressure air handling unit. The float member only lifts to allow water to flow from the first to the second duct when the first duct completely fills with water. When this occurs, no reverse flow of air occurs due to the fact that the first duct is full of water and therefore blocks the airflow. In this manner, the above-mentioned problems are alleviated.

Positive pressure air handling units are known in which air flows out of the unit along the condensate drain pipe. In this arrangement, the condensate drain outlet of the air handling unit is connected to the second duct. The float member only lifts to allow water to flow from the second to the first duct when the second duct completely fills with water. When this occurs, no reverse flow of air occurs due to the fact that the second duct is full of water and therefore blocks the airflow, Preferably the valve orifice is disposed in line with or radially outwardly of the first and second ducts.

Preferably the first and second ducts comprise respective longitudinal axes, which lie in a common plane, the float member being arranged to move normal to said plane within said float chamber.

Preferably the float member comprises a flat sealing surface which is arranged to seal against a flat sealing surface of the valve orifice.

Preferably said sealing surface of the valve orifice lies in a plane which extends parallel to said common plane and preferably parallel to a bottom wall of said valve body.

An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a liquid flow valve in accordance with the present invention; Figure 2 is a vertical sectional view through the valve of Figure 1; and Figure 3 is sectional view along the line Ill -Ill of Figure 2.

Referring to the drawings, there is shown a liquid flow valve comprising a one-piece valve body 10 of thermosetting plastics material. The valve body 10 comprises a cylindrical float chamber 15 having a tubular side wall 14, a bottom end wall 11 and an open top. A circular cover (not shown) is provided for fitting to the open top of the chamber 15. The body 10 further comprises first and second tubular ports 12,13 extending outwardly from the tubular side wall 14 at diametrically opposed positions adjacent the bottom end thereof. The ports 12,13 define sockets for connecting to respective portions of a liquid flow pipe (not shown) such as a condensate drain pipe of an air handling unit.

The second port 13 opens directly into the bottom of the float chamber 15. The first port 12 extends through the tubular side wall 14 into the chamber 15. The inner end of the first duct 12 is closed by a C-shaped end waIl 16, which extends upwardly from the bottom wall 11 of the chamber 15. The upper end of the C-shaped end wall 16 defines a part of a circular valve orifice 17 formed in the side wall of the first duct 12.

The valve orifice 17 comprises a fiat planar valve surface which faces upwardly into the float chamber 15. The valve surface lies in a plane which extends parallel to the bottom wall 11 of the chamber 15 and parallel to a plane in which the longitudinal axes of the ducts 12, 13 extend.

A float 18 having a flat bottom surface is disposed inside the float chamber 15 for sealing against the valve orifice 17. Guide means such as a guide rod (not shown) are provided for constraining the float 18 against lateral movement in the float chamber 15.

In use, the first port 12 is connected via an elongate pipe to the condensate outlet of a negative pressure air handling unit. The second duct 13 is connected to an external drain via a further elongate pipe. The ports 1213 are located adjacent the bottom end wall 11 of the valve body 10 thus the valve can be fitted to pipes which run in close proximity to the floor without raising the level of the pipes.

As condensate is produced by the air handling unit, the collected water flows into the valve through the first port 12. When the first port 12 has completely filled with water, the water lifts the float 17 to allow excess water to flow over the C-shaped walIl6 and into the bottom of the chamber 15, where it flows out of the second port 13. When the float 17 is raised, no reverse flow of air enters the air handling unit due to the fact that the first port 12 is completely full of water and therefore blocks the airflow. At other times, the float 18 closes the valve orifice 17 to prevent the reverse flow of air.

In an alternative mode of use, the second duct 13 can be connected to the condensate drain outlet of a positive pressure air handling unit. When the second port 13 completely fills with water, the float 18 is lifted to allow the water to flow into the first port 12. At other times, the float 18 remains seated across the valve orifice 17 to prevent the flow of air out of the air handling unit and to prevent the reverse flow of any contaminates.

A liquid flow valve in accordance with the present invention is simple and inexpensive in construction, yet is able to reliably close the condensate drain of a positive or negative pressure air handling unit. The valve does not require any maintenance since the valve member closes the valve orifice at all times when there is no water flow through the valve.

Claims

CLAIMS1. A liquid flow valve comprising a valve body having first and second liquid flow ducts in fluid communication with a float chamber disposed inside the valve body, and a float member disposed inside the chamber for closing a valve orifice which connects said first duct to said chamber, wherein the float member is arranged to remain seated across the valve orifice until the first or second duct has completely filled with liquid.
2. A liquid flow valve as claimed in claim 1, in which the valve orifice is disposed in line with or radially outwardly of the first and second ducts.
3. A liquid flow valve as claimed in claims 1 or 2, in which the first and second ducts comprise respective longitudinal axes, which lie in a common plane, the float member being arranged to move normal to said plane within said float chamber.
4. A liquid flow valve as claimed in any preceding claim, in which the float member comprises a flat sealing surface which is arranged to seal against a flat sealing surface of the valve orifice.
5. A liquid flow valve as claimed in claim 4 as appended to claim 3, in which said sealing surface of the valve orifice lies in a plane which extends parallel to .. : said common plane.I*,s* 25
6. A liquid flow valve as claimed in claim 5, in which said sealing surface of the *...

* ...: valve orifice lies in a plane which extends parallel to a bottom wall of said valve body. V V I...
7. A liquid flow valve substantially as herein described with reference to the accompanying drawings.