Apparatus for visually monitoring and controlling the liquid flow in a pressure line

A pressurized liquid conduit is broken or interrupted to provide an upstream inlet into a downstream outlet from a visual monitoring device. The device, which includes a collection chamber surrounding the conduit outlet and a transparent tube extending upwardly therefrom surrounding the upstream inlet is sealed in air tight relation around the liquid line on either side of the interruption. An air lock or bubble, greater in volume than the volume of the transparent tube, is contained in the chamber/tube assembly to maintain a constant pressure on the liquid collected in the chamber causing a controlled flow of liquid through the downstream side of the line. A baffle in the collection chamber disperses air bubbles, which might tend to form in the collected liquid, prior to the time the air bubbles reach the outlet in the chamber.

BACKGROUND AND SUMMARY OF THE PRESENT INVENTION 
This invention relates to the monitoring of a liquid such as water through 
a pressurized opaque line. In certain types of industrial or commercial 
environments, it is often necessary to maintain a reservoir or tank of 
water or other liquid full or at a desired level at all times in order to 
provide for humidity control or similar situations. Generally, in such 
situations, the water or liquid in the tank is constantly being used, and 
therefore a constant flow of liquid into the tank must be provided. For 
example, in a lumber kiln, there is provided a "wet bulb box" within the 
kiln which receives a supply of water from a pressure line, which water is 
picked up by a wick and evaporated into the atmosphere of the room by the 
flow of air thereover. The water is constantly being used, and therefore 
must constantly be supplied to maintain the wet bulb box at a fluid level 
that slightly overflows at all times (so operator can determine if 
sufficient water is present). 
In certain installations, this is a relatively easy task. For example, 
imagine a water trough in which the water is constantly being drained out 
an opening in the lower area thereof. It is a relatively simple matter to 
adjust the valve of a faucet which delivers water into the trough to 
supply water at the same rate at which it is being withdrawn. On the other 
hand, imagine a watering trough in which the operator cannot visually see 
the output from the faucet into the trough, as is the case in a reservoir 
of the type in which the supply line to the reservoir actually introduces 
the water below the water level. To further complicate the situation, in a 
kiln or similar atmosphere, it may be dangerous for an operator to enter 
the kiln, if the temperature and moisture conditions are too high, to 
inspect the wet bulb box. Float valves have proven generally 
unsatisfactory because of their tendency to become clogged. 
It therefore becomes highly desirable to be able to easily monitor and 
control the flow of water or liquid through the opaque pressurized feed 
line at a point outside of the kiln or other operating environment. This 
cannot be accomplished merely by making a portion of the feed line 
transparent, because in a pressurized line situation, the water always 
fills the feed line, and a visual inspection will not allow the operator 
to determine the rate of water flow. 
It is this type of situation and problem which the present invention 
attempts to overcome. Short of elaborate controls, there is no known 
apparatus available for visually monitoring and controlling the flow of 
liquid through a pressurized line other than at the outlet thereof. 
In general, the approach adopted in the present invention is to provide an 
interruption or intermediate outlet in a vertical section of an opaque 
pressurized liquid line allowing the liquid to fall at a prescribed rate 
through a transparent tube into a collection chamber. The collection 
chamber and transparent tube are sealed to the upstream and downstream 
portions of the conduit, as well as to each other. The sealing creates an 
"air lock, " which as used herein describes the condition which exists as 
the air pressure within the collection chamber and transparent tube 
increases as the inlet valve is opened and liquid begins to fill the 
collection chamber. Eventually the air pressure will overcome the back 
pressure created by the liquid in the downstream portion of the conduit 
and cause the liquid to flow out of the collection chamber at the same 
rate that it is being introduced through the inlet valve. Once an 
equilibrium situation is established, the level within the collection 
chamber remains the same unless back pressure in the downstream line or 
leakage of the air from the chamber occurs. Thus the air lock serves the 
dual purpose of keeping the transparent tube evacuated which would 
otherwise obstruct the visual monitoring of the fluid liquid flow, and of 
maintaining sufficient pressure in the line to move the liquid out of the 
collection chamber at the same rate at which it is entering. The fluid 
flow may vary from a lazy stream to individual droplets being emitted 
through the observation tube and into the collection chamber, however, 
because the transparent observation tube is kept free of liquid and is 
large enough that the liquid being emitted from the outlet of the upstream 
portion does not engage the sides thereof, a clear monitoring of the 
stream size therethrough is possible. 
The apparatus according to the present invention then permits visual 
inspection and adjustment of the flow rate of the liquid, while 
maintaining pressurized system which ensures continuous flow at the 
prescribed rate to the desired destination. Toward this end, an 
interruption or intermediate enclosed outlet in the pressure line provides 
for the free fall of the liquid for a prescribed distance through which 
the liquid is surrounded only by the transparent tube and is thus visible. 
A control valve is interposed in the pressure line upstream (or even 
downstream) of the intermediate outlet to vary the flow of liquid 
therethrough as is necessary to maintain the proper level in the 
reservoir. A visual monitoring means downstream of the valve surrounds the 
intermediate outlet in sealing arrangement thereto and includes a 
collection chamber attached to the upstream end of the downstream portion 
of the conduit, which chamber has a volume considerably greater than the 
instantaneous volume of fluid collected therein at any one time. The 
collection chamber has an opening in the upper end thereof for receiving 
the incoming liquid stream therethrough. A length of transparent tubing 
connects the opening in the upper wall of the collection chamber with the 
downstream end of the upstream portion of the conduit. The transparent 
tube is of an inner diameter substantially greater than the inner diameter 
of the conduit and considerably smaller than the inner diameter of the 
collection chamber, however, the inner diameter of the transparent tube is 
large enough that the stream or droplets being emitted from the orifice of 
the upstream conduit do not engage the side walls as they expand at the 
outlet (in the case of droplets) or otherwise engage the side wall of the 
transparent tube in the case of a tube that is slightly askew from the 
vertical. Also, the diameter of the transparent tube should not be too 
large, because the collection chamber would have to be enlarged. The 
housing and transparent tubing are connected to the conduit around the 
interruption in substantially air tight arrangement. An air lock is 
provided in the chamber and transparent tubing, the volume of which is 
greater than the volume of the tubing. As a result of the air lock the 
fluid leaves the chamber at the same rate that it enters and the normal 
fluid level tends to remain within the collection chamber rather than 
rising up within the observation tube. 
It is therefore an object of the present invention to visually monitor the 
flow of liquid through a pressurized line at a point upstream of the 
outlet thereof without interrupting the rate of flow therethrough. 
It is another object of the present invention to provide a means for 
maintaining a constant level of liquid in a reservoir from which the 
liquid is constantly being removed, which liquid is being delivered to the 
reservoir through a pressurized opaque line, from a point remote from the 
reservoir.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
Turning now to the drawings there is illustrated in FIG. 1 the environment 
in which the liquid monitoring device of the present invention is 
installed. An opaque liquid line 10 extends from a source or supply 12 to 
a reservoir 14 through which liquid is delivered under pressure. Reservoir 
14 is positioned within a work area requiring a constant controlled supply 
of water or liquid for the purpose of controlling humidity, such as a 
drying kiln, the wall of which is represented at 11. The reservoir 14 
includes a wet bulb sensor 16 to measure "wet bulb" temperature. This is 
conventionally referred to as a "wet bulb box." The liquid line 10 
delivers liquid into the bottom of reservoir 14. It is desired that this 
reservoir 14 from which water or other liquid is continuously being 
withdrawn be maintained full or slightly overflowing. As stated 
hereinabove, it is generally not always feasible for an operator to enter 
the kiln during the operating times. 
In order to monitor and control the delivery of liquid to box 14, the 
opaque pressure line 10 is interrupted upstream the outlet thereof and 
outside the wall 11 of the kiln. A visual monitoring means 20 of the 
present invention is emplaced at the point of interruption. Immediately 
above the visual monitoring means 20 there is provided a control valve, 
preferably in the form of needle valve 18, which can be adjusted to 
introduce a prescribed flow of liquid into the visual monitoring means 20. 
FIG. 2 is an enlarged illustration, in section, of the visual monitoring 
means 20 which is emplaced between the downstream end of the upstream 
portion 10a of the pressure line 10 and the upstream end of the downstream 
portion 10b of conduit 10. Reference numeral 10c represents the actual 
outlet or orifice of the downstream end of upstream portion 10a. A 
collection chamber 22 is emplaced in operative, but sealed arrangement 
around the upstream end of downstream portion 10b. Housing 22 includes a 
preferably cylindrical side wall 24, a bottom wall 26, and a top wall 28. 
A passageway 27 extends through the bottom wall 26 into communication with 
the downstream conduit portion 10b so that liquid being collected within 
chamber 22 is forced out into conduit 10b through the passageway 27. 
There is further provided an opening 29 in the upper wall 28 which receives 
therein the lower end of a transparent observation tube 34. A plastic 
collar 36 serves to connect the upper end of the observation tube 34 with 
the downstream end of the upstream portion 10a of conduit 10 immediately 
below valve 18. The collar 36 serves to attach the observation tube 34 in 
sealing or air tight relation to the conduit 10a even if and when the air 
pressure within the observation tube 34 exceeds atmospheric pressure. 
Likewise, the lower wall 26 of housing 22 is sealed in air tight relation 
to the downstream conduit portion 10b even under such conditions that the 
air pressure within housing 22 exceeds atmospheric pressure. 
Observation tube 34 is hollow and the previously described air lock is 
formed by the hollow interior 38 of tube 34 and the area 40 within chamber 
22 above the level of the liquid 42 collected therein. The aforesaid air 
lock maintains a greater than atmospheric air pressure within the housing 
22 which tends to force liquid out passageway 27 at the same rate at which 
it is being introduced into housing 22 from the outlet 10c of the upper 
conduit portion 10a. As the valve 18 is adjusted to permit a greater or 
lesser flow of liquid, the air lock 38,40 will tend to force more or less 
liquid through passageway 27 at the corresponding rate. It should be noted 
here that the observation tube 34 must be of a sufficient inner diameter, 
that, neither water droplets or the stream of water emitted from orifice 
10c substantially engage or impinge upon the walls of tube 34. When 
droplets form at the outlet 10c of upper conduit portion 10a during such 
times that drops are being delivered, should the droplets enlarge and 
impinge upon the wall of tube 34, this would tend to obscure the 
visibility of the stream or droplets being emitted therethrough. 
As a stream of water or liquid falls into the body of water 42, there tends 
to form air bubbles as a result of cavitation within the body of liquid, 
depending upon the force with which the stream is being delivered. Such 
air bubbles might ordinarily tend to work their way out passageway 27, 
however, a baffle 32 is provided on the lower wall 26 of housing 22 which 
tends to disburse the air bubbles. Baffle 32 slants upwardly from lower 
wall 26 to a point overlying passageway 27. 
A pair of ears or protrusions 30 extend outwardly from either side of 
housing 22 to provide an attachment means for the housing 22 to a wall or 
equipment casing. 
In use, valve 18 is adjusted to maintain the reservoir or wet bulb box 14 
at a prescribed level. The velocity or rate of flow of fluid being emitted 
from the outlet 10c can then be noted. If the liquid level begins to drop, 
as indicated by the wet bulb temperature or as by noted visually valve 18 
may be opened slightly and the rate of flow then noted by visually 
inspecting tube 34. Conversely, if the reservoir 14 overflows too much, 
the valve 18 may be closed slightly. Should the level of liquid 42 in the 
reservoir 22 rise to the point that it is visible in tube 34, this is a 
sign that there is a blockage in the downstream conduit portion 10b or 
that there is an air leak. To prevent such blockages, periodically (such 
as daily) the valve 18 should be opened for a few seconds to allow a 
strong flow of liquid therethrough, which will tend to flush the 
downstream portions of the line. Immediately upon flushing, the valve can 
be returned to a position where the desired rate of flow, as noted through 
the observation tube 34 is maintained. In the case of an air leak, the 
housing 22 can be removed and replaced or repaired. Thus, in normal usage, 
the level of the body of liquid 42 should remain the same. 
While a preferred embodiment of the present invention has been described in 
detail hereinbelow, it is apparent that various changes and modifications 
might be made without departing from the scope of the invention which is 
set forth in the accompanying claims.