Controlling concentration of additive in an evaporative system

Claim 3

A device as claimed in claim 1, characterized in that said means (a) for measuring Fm comprises a disc with a central calibrated orifice mounted inside the make up water feed pipe, an instrument detecting the pressure differential ( Delta p) between the zone upstream of said disc and the zone downstream thereof, said instrument being connected to said zones by two separate branch pipes and communicating with a square root extractor for linearizing the corresponding signal.

Claim 4

A device according to claim 1 characterized in that said means (b) for continuously measuring the ratio Km/Ks consist of two conductivity cells, each fed separately with a continuous sampling of the make up water and of the blow down water, and forming two contiguous sides R1 and R2 of a Wheatstone bridge the third side of which (R3) consists of a variable resistor, while the fourth side of which (R4) consists of a variable resistor moveable by a zeroing device to produce an output signal, means being also provided for transforming the electric signal given out by said bridge into a pneumatic signal representing the Km/Ks ratio.

Claim 5

A device according to claim 2 characterized in that said means (b) for continuously measuring the ratio Km/Ks consist of two conductivity cells, each fed separately with a continuous sampling of the make up water and of the blow down water, and forming two contiguous sides R1 and R2 of a Wheatstone bridge the third side of which (R3) consists of a variable resistor, while the fourth side of which (R4) consists of a variable resistor moveable by a zeroing device to produce an output signal, means being also provided for transforming the electric signal given out by said bridge into a pneumatic signal representing the Km/Ks ratio.

Claim 6

A device as claimed in claim 3, characterized in that said zeroing device consists of means responsive to the sensing diagonal of the Wheatstone bridge to adjust the fourth side (R4) to zero and concurrently adjusting a potentiometer which delivers an output electric signal proportional to Km/Ks.

Claim 7

A device as claimed in claim 3, characterized in that said third resistor (R3) of the bridge is positioned by a pneumatic device linear with the flow rate Fm.

Claim 8

A device according to claim 1, characterized in that said analog means (c), comprises a square root extractor and a multiplier.

Claim 9

A device as claimed in claim 1, characterized in that the variable stroke of said pump (d) is continuously adjusted by a signal coming from the measuring means for thE rate of flow of the make up water Fm and the variable speed of the pump driving motor by the signal coming from the measuring device for the ratio Km/Ks, or vice versa.

Claim 10

A device as claimed in claim 6, characterized in that the variable stroke of the pump is directly controlled by the output signal from the Wheatstone bridge, directly proportional to the flow rate of the blow down water.

Claim 11

Apparatus for continuous dosage of chemical additives in a plurality of evaporative systems, each system including both make up water and blow down water, and a central control station for the evaporative systems, said station comprising: a. means for continuously measuring make up water flow rate (Fm) and for transmitting signals indicating the measured rate of flow; b. means for continuously measuring the ratio Km/Ks of the relative conductivities of the make up water and of blow down water and for transmitting signals indicative of the measured ratio; c. analog means for multiplying said two signals indicative of the values of Fm and of Km/Ks and for transmitting signals indicative of the product of said two signals; and d. pump means of variable stroke for feeding the chemical additive, with a pneumatic governor of said stroke controlled by the pneumatic signal derived from said analog means; said apparatus further comprising a group of main pipes extended from said control station and group of secondary pipes extended respectively from each of said evaporative systems, valve means for connecting sequentially the pipes in the main group respectively to pipes in the secondary groups, there being five pipes in each group as follows: two pipes enabling the central control station to measure Fm, the third pipe being a sampling pipe for the make up water, the fourth pipe being a sampling pipe for the blow down water, and the fifth pipe being a return pipe for the water containing the additive; the sequence of the time intervals of connection of said main group of pipes to said secondary pipes and the duration of said intervals being governed by a timer proportionally to the maximum nominal rates of flow of the make up water in the different evaporative systems.

Claim 12

Apparatus for continuous dosage of chemical additives in a plurality of evaporative systems, each system including both make up water and blow down water, and a central control station for the evaporative systems, said station comprising: a. means for continuously measuring make up water flow rate (Fm) and for transmitting signals indicating the measured rate of flow; b. means for continuously measuring the ratio Km/Ks of the relative conductivities of the make up water and of blow down water and for transmitting signals indicative of the measured ratio; c. analog means for multiplying said two signals indicative of the values of Fm and of Km/Ks and for transmitting signals indicative of the product of said two signals; and d. pump means of variable stroke for feeding the chemical additive, with a pneumatic governor of said stroke controlled by the pneumatic signal derived from said analog means; said apparatus further comprising a group of main pipes extended from said control station and group of secondary pipes extended respectively from each of said evaporative systems, valve means for connecting sequentially the pipes in the main group respectively to pipes in the secondary groups, there being five pipes in each group as follows: two pipes enabling the central control station to measure Fm, the third pipe being a sampling pipe for the make up water, the fourth pipe being a sampling pipe for the blow down water, and the fifth pipe being a return pipe for the water containing the additive; the sequence of the time intervals of connection of said main group of pipes to said secondary pipes and the duration of said intervals being governed by a timer proportionally to the maximum nominal rates of flow of the make up water in the different evaporative systems.

Claim 13

Apparatus for continuous dosage of chemical additives in a plurality of evaporative systems, each system including make up water derived from a common source and blow down water, and a central control station for the evaporative systems, said station comprising: a. means for continuously measuring make up water flow rate (Fm) and for transmitting signals indicating the measured rate of flow; b. means for continuously measuring the ratio Km/Ks of the relative conductivities of the make up water and of blow down water and for transmitting signals indicative of the measured ratio; c. analog means for multiplying said two signals indicative of the values of Fm and of Km/Ks and for transmitting signals indicative of the product of said two signals; and d. pump means of variable stroke for feeding the chemical additive, with a pneumatic governor of said stroke controlled by the pneumatic signal derived from said analog means; said apparatus further comprising a group of main pipes extended from said control station and group of secondary pipes extended respectively from each of said evaporative systems, valve means for connecting sequentially the pipes in the main group respectively to pipes in the secondary groups, the pipes in each group comprising: a sampling pipe for the blow down water and a return pipe for the additive.

Claim 14

Apparatus for continuous dosage of chemical additives in a plurality of evaporative systems, each system including make up water derived from a common source and blow down water, and a central control station for the evaporative systems, said station comprising: a. means for continuously measuring make up water flow rate (Fm) and for transmitting signals indicating the measured rate of flow; b. means for continuously measuring the ratio Km/Ks of the relative conductivities of the make up water and of blow down water and for transmitting signals indicative of the measured ratio; c. analog means for multiplying said two signals indicative of the values of Fm and of Km/Ks and for transmitting signals indicative of the product of said two signals; and d. pump means of variable stroke for feeding the chemical additive, with a pneumatic governor of said stroke controlled by the pneumatic signal derived from said analog means; said apparatus further comprising a group of main pipes extended from said control station and group of secondary pipes extended respectively from each of said evaporative systems, valve means for connecting sequentially the pipes in the main group respectively to pipes in the secondary groups, the pipes in each group comprising: a sampling pipe for the blow down water and a return pipe for the additive.