Improvements in and connected with the Utilization of Tidal Energy.
Year: 1893

page_text: Date of Application, 13th July, 1893
Complete Specification Left, 13th Apr., 1894-Accepted, 19th May, 1894 -
PROVISIONAL SPECIFICATION.
Improvements in and connected with the Utilization of Tidal
Energy.
I, NINIAN RUTHERFORD JAMIESON, of 32 William Street, Forebank, Dundee,
in the County of Forfar, N.B. Science Teacher, do hereby declare the nature of
this invention to be as follows:-
My invention relates to Improvements in and connected with the Utilization of
Tidal Energy, my object being to transform the potential energy of the tides into
useful energy or work.
"
In carrying out my invention, I construct a reservoir in any known manner,
allow it to be filled at high tide, and utilize the "head" thus obtained at low
tide, and conversely. In both cases the "head" may be used in actuating turbines
or other water motors. The energy thus obtained is transformed either directly
into mechanical work, or by means of dynamos and the like, into electrical energy
for lighting, power transmission, storage in secondary batteries and such like.
The bottom of the reservoir should be under the low water level in order to
obtain the greatest efficiency. A sluice, sluices, or other form of valve may be
situated in the reservoir wall, or in connection with same, in order that such
reservoir may be rapidly emptied or filled if required, such sluices not having
any direct communication with the water motors. One or more turbines, or other
water motors suitably provided with water passages are so arranged, that with a
difference of level between the "sea" and reservoir,
66 sea being greater, such
motors are actuated, and conversely. For example:-Should a vertical axial
flow turbine be used, the inflow to turbine (top) will be connected to both "sea
and reservoir and the outflow (bottom) will be similarly connected. Sluices or
other valves are employed to control the inflow of water to the turbine (a) to
or from the sea, (b) to or from the reservoir (c) to control the outflow of water
to or from the sea (d) to or from the reservoir. Breakwaters may be used to
protect the passages to or from the motors. The motors are operated in the
following manner. At high water let reservoir be full. Close all exit sluices and
allow tide to recede. About low tide open the motor valves and permit the water
in the reservoir to actuate these with a "head due to the difference in level
between reservoir and "
sea."
When the difference in level becomes so small as
not to allow of the economical working of the motors, the remainder of the water
may be rapidly run off, by means of the before mentioned sluices.
"
Again, at low water close all inlet sluices to reservoir and when tide rises,
actuate the motors by the converse flow of water. It is to be noted that it is
advantageous in my system that levels change more slowly before and after "ebb"
and "flood."
If turbines be used they should be driven in order to obtain highest efficiency at
correct speed for respective "heads." As efficiency varies slowly on each side of
best speed advantage may be taken of this, and when difference in working heads
is not considerable, and it is found advantageous to have say a turbine running at
a constant speed, such may be done. As the work done varies as load into velocity,
therefore load should be varied as required.
Dated this 10th day of July 1893.
GEO. C. DOUGLAS & Co.,
41, Reform Street, Dundee, Agents for Applicant.

page_text: Improvements in and connected with the Utilization of Tidal
Energy.
I, NINIAN RUTHERFORD JAMIESON, of 32 William Street, Forebank, Dundee,
in the County of Forfar, N.B. Science Teacher, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
My invention relates to Improvements in and connected with the Utilization of
Tidal Energy, my object being to transform the potential energy of the tides into
useful energy or work.
"
66
"
-
In carrying out my invention, I construct a reservoir in any known manner,
allow it to be filled at high tide, and utilize the "head" thus obtained at low tide,
and conversely. In both cases the "head" may be used in actuating turbines or
other water motors. The energy thus obtained is transformed either directly into
mechanical work, or by means of dynamos and the like, into electrical energy for
lighting, power transmission, storage in secondary batteries and such like. The
bottom of the reservoir should be under the low water level in order to obtain the
greatest efficiency. A sluice, sluices, or other form of valve may be situated in
the reservoir wall, or in connection with same, in order that such reservoir may be
rapidly emptied or filled if required, such sluices not having any direct communi-
cation with the water motors. One or more turbines, or other water motors
suitably provided with water passages are so arranged, that with a difference of
level between the " and reservoir,
sea
sea being greater, such motors are
actuated, and conversely. For example:-Should a vertical axial flow turbine be
used, the inflow to turbine (top) will be connected to both " sea and reservoir and
the outflow (bottom) will be similarly connected. Sluices or other valves are
employed to control the inflow of water to the turbine (a) to or from the sea, (b) to
or from the reservoir (c) to control the outflow of water to or from the sea (d) to or
from the reservoir. Breakwaters may be used to protect the passages to or from
the motors. The motors are operated in the following manner. At high water
let reservoir be full. Close all exit sluices and allow tide to recede. About low
tide open the motor valves and permit the water in the reservoir to actuate these
with a "head" due to the difference in level between reservoir and "
sea." When
the difference in level becomes so small as not to allow of the economical working
of the motors, the remainder of the water may be rapidly run off, by means of the
before mentioned sluices.
Again, at low water close all inlet sluices to reservoir and when tide rises,
actuate the motors by the converse flow of water. It is to be noted that it is
advantageous in my system that levels change more slowly before and after "ebb".
and "flood."
If turbines be used they should be driven in order to obtain highest efficiency at
correct speed for respective "heads." As efficiency varies slowly on each side of
best speed advantage may be taken of this, and when difference in working heads
is not considerable, and it is found advantageous to have say a turbine running at a
constant speed, such may be done. As the work done varies as load into velocity;
therefore load should be varied as required.
And in order that my said invention may be properly understood I now
proceed more particularly to set forth the system, mode or manner in or under
which the same is or may be used, or practically carried into effect, reference being
made to the accompanying drawings, and to the letters and figures marked thereon,
that is to say :-
Figures 1. to 11. (Sheet 1.) illustrate in a diagrammatic manner the fundamental

page_text: principles relating to the discharge and filling of reservoirs, the letter S referring
to sea or the like and R to the reservoir.
66
"
Figure 12. (Sheet 1.) shows a curve of levels giving the rate to rise or fall.
Figure 13. (Sheet 2.) illustrates in a partially diagrammatic manner the general
arrangement of a tidal power house with a vertical axial flow turbine in position.
Figure 14. (Sheet 3.) shows velocity and time curves, illustrating the discharge
of water from an orifice.
Figure 15. (Sheet 4.) shows curves of available power, head and load for best
speed, and velocity of discharge together with a table of numerical results.
Figure 16. (Sheet 5.) illustrates diagrammatically the fact that in order to obtain
greatest efficiency when water flows from the reservoir, its depth need not be so
great as that of the sea.
Figure 17. (Sheet 5.) is a plan of an estuary, the shaded portions of which
represent suitable sites for reservoirs.
Figure 18. (Sheet 5.) shows the curve of a suitable turbine wheel vane.
Figure 19. (Sheet 5.) shows the efficiency and quantity of water curve of such a
turbine.
Figure 20. (Sheet 6.) illustrates a form of sluice.
Figure 21. (Sheet 6.) illustrates a method of keeping tight the joints of such
sluices.
Figures 22. and 23. (Sheet 6.) respectively illustrate an elevation and a plan of
a modified form of the sluice.
Figure 24. (Sheet 6.) shows diagrammatically a form of pulley used in connection
with dynamos.
Figure 25. (Sheet 6.) shows a curve of levels, giving the rate of rise and fall of
the tides.
Figure 26. (Sheet 6.) illustrates a method of working a turbine with two
reservoirs.
Figure 27. (Sheet 6.) illustrates yet another method of utilizing the flow of
water for driving a turbine.
Figures 28. and 29. (Sheet 6.) illustrate respectively in elevation and plan a
method of arresting the flow of mud and sand into the reservoir.
The first part of my invention refers to the method of filling and discharging the
reservoir to suit the rise and fall of the tide. Starting at full tide, Figure 1, all
exit sluices from the reservoir are closed. Low tide is indicated by Figure 2, the
If it be
head shown therein being utilized in the actuating of, water motors.
assumed that the time of discharge is inappreciable Figure 3. indicates the third
stage of the cycle. Again, starting at low tide (Figure 3.) all inlet passages
from the sea are closed; Figure 4. showing full tidal head which may be utilized
in a similar manner to that previously explained, Figure 1. showing the final stage
of the cycle.
The results represented by Figures 1. to 4. in practice can only be approximately
arrived at. For example:-Commencing with the condition represented in Figure 1.
that of Figure 2. might not be reached, since during the time of discharge the tide
might rise considerably, and Figure 5. might more nearly represent the actual
conditions. Consequently at next full tide the levels in S. and R. would be
represented by Figure 6. and not by Figure 4.
Commencing then operations with condition Figure 6. the condition Figure 1.
might not be reached since during the time of filling the tide might ebb considerably,
and so condition Figure 7. would ensue.
It therefore follows with such a method of working, that there will be an initial
depth of water in the reservoir when commencing to fill it at full tide, and there.
will not be full tide level in reservoir when commencing to discharge it at low tide,
heuce the more efficient method of working will be to commence to discharge
reservoir with the tide ebbing as at M. (Figure 8); M's level being so adjusted
that when the reservoir has discharged to M. the tide will have risen to M.
(Figure 9). Similarly the reservoir commences to fill when the tide has risen to N.

page_text: (Figure 10.) N's level being so adjusted that when the reservoir has been filled
to N. the tide will be ebbing at N. (Figure 11). The average head in S. and R.
will be a little over
N.M.
It is of importance to note when working according to the aforesaid system that
levels change most slowly immediately before and after "ebb" and "flood,"
consequently the loss through F.N. and M.E. (Figures 8. to 11.) is reduced to a
minimum. This fact is graphically shown by the curved Figure 12. which
illustrates the rate of change of tide level. Now while it is important in order to
take full advantage of the tidal energy, to minimize the time of discharge and
filling of reservoir, unless such time is considerable, the capacity of power
absorption plant must necessarily be great. Since however the rates of "ebb" and
"How" (Figure 12) are least immediately before and after high and low water,
considerable time may be devoted for this purpose without excessive loss.
Figure 13. illustrates one method of arranging the passages, sluices and such
like of a tidal power house, as adapted for a vertical axial flow turbine. The
inflow to and outflow from turbine T. is connected with both " sea "and reservoir.
Sluices S₁ and S, or other form of valve control the inflow of water to the
turbine (a) from the sea. (b) from the reservoir. Similar sluices or valves S3
and S, control the outflow of water from the turbine. (c) to the sea. (d) to the
reservoir.
The motor or motors T. are operated in the following manner. About high tide
when the reservoir is full, close all exit passages and allow the tide to recede.
About low tide open S, and S, and permit the water in the reservoir to actuate
the motor T. with a head due to the difference in level between reservoir and sea.
When the difference in level becomes so small as not-to allow of the economical
working of the motors-either through taking up too much time and consequently
allowing a considerable rise of tide; or through the practical difficulties involved
in working the motor with too small a head the residue water may be rapidly run
away by means of the sea wall sluices. The next operation is to close all inlet
sluices and allow the tide to rise to nearly its maximum, open the motor sluices S₁
and S, and permit the water in sea to actuate the motor with a head. due to the
difference in level between sea and reservoir. When this difference in level
becomes so small as not to allow of the economical working of the motors, the
reservoir may be fully filled up by means of the sea wall sluices.
Certain facts regarding the discharge of water from an orifice are graphically
illustrated by Figure 14. V.N. is the velocity curve and T.L. the time curve.
Horizontal ordinates to V.N. represent the comparative velocities of discharge
under corresponding heads, and horizontal ordinates to T.L. the comparative times
required to discharge a given quantity. The time taken to discharge or fill the
whole reservoir is represented by the total area T.L.M.N. and the time taken
between any two "heads is represented by the area enclosed between the
horizontal ordinates to the time curve at such respective heads, the velocity of
discharge varying as ✓h. It therefore follows that I may work with lower
"heads" because the time of discharge and filling of the reservoir is not increased
proportionately.
I will now give a calculation showing how to determine the available power of a
given tidal system with a reservoir of one square mile area, and assuming a spring
tide with a level difference of 16 feet, also assuming that the time interval between
high and low tide is exactly six hours.

page_text: conditions the available H.P. will be one fourth, i.e. there is half the weight raised
through half the height = one fourth the work, or 4690 H.P. night and day.
In Figure 15. horizontal measurements indicate the time of discharge and
vertical ordinates (a) the power available, (b) the corresponding "head," and also
if a turbine be used the load for best speed, and (c) the corresponding velocity of
discharge, quantity of water, and the best speed for a turbine. The table again,
gives certain data in reference to the discharge of a reservoir of one square mile
area and sixteen feet "head" upon the assumption that the sea level remains
constant. 16 ft. to 15 ft. "head" is taken as 15.5 ft. and so on. This, while not
strictly accurate is nearly so, the total time taken being about 216 minutes.
order to reduce the time of discharge and so maintain the sea level approximately
constant, there are two alternatives viz.: (a) to largely increase the capacity of the
inotor plant, that is to say the discharge area, or (b) to work only between
certain "heads," and run the remainder of the water rapidly out, or in, through the
sea wall sluices.
In
Now it will be noted that it is in the discharge of the water when the lower
"heads" obtain, that the most time is required, (Figure 15 and table), while the
power available with these low "heads" is comparatively small, Figure 15, being
equal to (h); consequently there are strong economic, as well as practical
=
reasons for in many cases adopting the second alternative. The available work
"in" a discharge or filling of reservoir, or a part of same, varies as the difference
between the working levels into the mean level. With a 16 ft. reservoir the total
work will therefore be comparatively speaking 16 x 8 = 128. Assuming that
the last four feet is run out through sea wall sluices the available work will
become 10 (164) = 120 and the work lost will be 4 x 2 = 8 or only 6% of the
total available energy, while the time saved is almost one half. A loss of one foot
at the highest pressure would be equivalent to a loss of energy represented
by 15.5 (16-15): 155 or about 12% This shows the importance of minimizing
time of discharge by working about a two hour period, this 12%-with the 16 ft.
tide-covering the loss sustained. In the table this one ft. head has been put
against such loss (although of course the change in level causes a small variation
from the table data and curves (Figure 15). The amended time now required is
about 109 minutes, leaving say 11 minutes for discharge by sea wall sluices.
With the loss of 12 + 6 = 18% the available H.P. over the square mile area is
reduced from 18770 H.P. to 15390 H.P. night and day. Again the loss with
the 8 ft. neap tide through the non-utilization of the last 4 ft. would be the same
in quantity but would === 25%. It will be observed however that if the motors
used are otherwise suitable, the time may be kept within say, the two hours,
although the difference between the heads is increased. Assuming this loss
of 25% and neglecting the other loss, the available power would be reduced
from 4690 to 3520 H.P. working night and day.
In order to know the amount of power absorption plant required, intensity of the
power developed at any time must be known. Then assuming a 2 hour's discharge,
this equals say 8 hours in the 24. The mean H.P. over the working period is
therefore (spring tide)·

page_text: nearly.
Figure 13. illustrates an axial flow turbine of the Jonval type. A turbine of
this class, of say 10.5 ft. mean diameter, measured to centre of buckets would pass
under a 15 ft. "head" about 490 cubic feet of water a second, and 125 of such
turbines would pass the discharge for a square mile area (see table Figure 15).
The efficiency at best speed of such a turbine may be about 80%, and under a
15 ft. "head" the available H.P. utilized by same would be about 850, giving
about 106000 for the 125 turbines, which is about equal to the greatest calculated
power.
With reference to the amount of water power plant required, it is to be noted
(a) that the working time is nearly as great as with the 8 hours and may be as
great as the average working day of a land steam engine, and any objection as to
excessive water power plant cannot hold good. (b) Although the H.P. varies
during the working periods from 7. to 1. the highest is only about double the mean,
and (c) the highest power is developed by the same number of turbines as is
required for the lowest, and (d) the mean power obtained, namely the mean "head"
compares favourably with the "heads" used in river turbine practice.
In the discharge of a reservoir working down to say a 4 ft. head, the bottom of
same need not be less than 4 ft. above low water level to obtain the highest
efficiency since the pressure will depend on the difference between reservoir and
sea level, and will not be affected by. the level of such reservoir bottom see
diagrammatic sketch Figure 16 and so the time required to empty reservoir of the
remaining 4 ft. of water would be saved, although in the filling of the reservoir,
to obtain highest efficiency, its bottom must be as low as low water level; since it
is in the filling of the lowest parts of the reservoir that the highest power is
developed.
If such an area, as was previously referred to, is enclosed, such as is frequently
found in river estuaries (Figure 17) where there are often large flats of sand or
mud uncovered at low tide; the highest efficiency would only be obtained in the
filling of reservoir when the level of its bottom had been brought down to that of
ebb tide. This could be gradually effected by means of dredgers.
If turbines be used as indicated in Figure 13. they ought to be driven at correct
speed for their respective heads (Figure 15).
Let E.E. Figure 18. indicate a vane passage. Let w. = vane velocity and
r. water velocity relative to vane, then a. will equal absolute water velocity and
direction of flow on entrance to vane and a₁ same on exit. If a. also represents
absolute velocity and direction of flow before entrance to vane i.e. through guides,
the condition obtains of no impulse and greatest efficiency. Hence with a given
"head
a turbine has a best speed. From which it follows, that in working under
the varying "head" necessary for the utilization of a considerable part of the tidal
force due to a given area, the turbine speed must be varied as the discharge or
filling up of the reservoir proceeds, if the highest efficiency is to be obtained.
Under conditions given, the horizontal component of the absolute velocity M.E.
at entrance, reduced to M₁E, at exit, therefore the horizontal acceleration
(M.E. M₁.E.) and since force = mass x acceleration; rotative force will
equal m (M.E. - M.E₁.) where m = the total mass of water acting on a vane at
once. Let t time of passage from E. to E₁. i.e. time required to produce the
acceleration (M.E. M.E.) then distance travelled by vane will equal t.w. work
=
done
-
-
-
(force x space) = f.t.w.
avoid impulse w. will become
W
2
==
m.t.w. (M.E. M₁.E₁.). Let a. become to
i.e. speed of rotation (best speed) varies as velocity

page_text: M.E.M₁.E₁.
2
M₁.E₁.).
But since r. now = this acceleration is only effected in double
the time (2.t.) therefore acceleration for t =
Distance travelled in t. will equal
t.w.
M.E.
×
= m.t.w.
2
1
.
-
8
M₁.E₁.\
t.w.
2
M.E.-M.E
4
and work done = f.t.w. (M.E.-M₁.E.).
=
4
2
or with half velocity of discharge, power =
1
27
(Figure 15); with velocity power = or work done and power developed varies
inversely as the cube of the velocity of discharge, or as the cube of the turbine
best speed. From the above it follows that if the machines driven, require to be
driven at a constant speed and the speed of the turbines is made to vary; some
form of variable gear must be used.
If each machine abstracts a considerable fraction of the tidal power of the
turbine or turbines, the knocking off, of the different machines will be equivalent
to a load which is decreasing in a more or less step by step manner, with a con-
sequent alternative gradual decrease and sudden increase in the speed, and this
will be the case whether the turbine speed is kept constant or at the least speed.
To avoid this, I may regulate the turbine by closing up as required some of the
guide passages in the known way, the operation being as follows. Assuming that
the turbine or turbines running together drive say sixteen machines at the highest
power. Close, to begin with, a number of the guide passages sufficient to bring
down the power to run only fifteen machines. As the available power decreases,
gradually open the closed guide passages again, keeping the turbines working at
the same power.
When the available water power has come down to fifteen, the
turbines will be running with full opening. Now knock off a second machine,.
bringing down load to fourteen, the speed would now be increased, but to prevent
this, close a number of the guide passages again, in this manner the power
developed will be kept constant during the running of a given number of machines.
The various channel terminals must be so arranged, as to provide the greatest.
possible natural protection from the influence of rough water.
Breakwaters should
be employed of sufficient strength to neutralize the calculated maximum dis-
turbance likely to occur in practice. The water motor speed will, in this manner,
be unaffected through variations in pressure due to wave motion. This may be
further insured by the use of flywheels F. W. (Figure 13.) which may also act as
rope or belt pulleys. There may be protected basins into which the motor channel
terminals may be placed. The inlet and exit passages may have a common
terminal and a number of water motors may have their various passages united in.
a common terminal, or breakwaters of other construction may be used.
The form of sea wall sluices would largely depend on the nature and extent of
the system, for example, some form of balanced or partially balanced valve might.
be adopted. In Figure 20. is shown the plan of a valve constructed on the
principle of the balanced throttle valve, pivoted at P; V. S. being the valve seats,.
the joints being kept tight in the following manner :--
The valve is provided along the line of contact with its framework, that is to
say at the joint where the water might escape, with a strip of leather or other
suitable material. It is preferably in the form of a tube, and provided with inside
springs, or compressed air, or water or other fluid, as to ensure perfect contact.
Such attachment may be also fixed to the framework, or to both valve and frame-
work as may be desired. Another method of keeping the joints tight consists in
the use of a lever or levers L. (Figure 21.) attached to the valve, or the framework,
and provided with springs S. so arranged that the tube T. will exert a pressure
along the joint.

page_text: Although I have described certain forms of valves, yet other types of valve may
also be used, as may be found most suitable for each individual case. A feature of
the special types I have alluded to, is the method of maintaining a water tight
joint, the "true" surfaces of contact being minimized because the contact surface
of the attachment conforms to the various irregularities of the surface it is pressed
against. Another type of sluice is illustrated in Figures 22. and 23. and is a
modification of that shown in Figure 20. This valve is rotated continuously in
opening and closing. F. is the framework for supporting the vertical and upper
gate journal J. The bevel wheel B. is preferably driven directly by an electric
motor M. and the gate is prevented from reversing its direction of rotation by a
ratchet wheel R. The sea wall at A. A, is curved to the arc of a circle so
that although the gate may not be exactly in its normal position, it may still be
closed.
If the motor speed-by motor is to be understood the motors driven by the
turbines is kept constant as the turbine's power decreases the different machines
may be "knocked off" in succession. If the turbine speed alters say between a
16 ft. and a 4 ft. head from 4 to 2, the driven pulley say must vary in diameter
from 2 to 4 see ouro 21

page_text: reservoir A. may be kept continuously at high tide level, and B. at low tide. The
system may thus work continuously night and day at an approximately constant
head, neglecting variations due to spring and neap tides. Again the system may
be worked continuously night and day at a constant head during both spring and
neap tides, by running the water from reservoir A. (Figure 27.) to a "lead"
lower level L. during spring tide, and by raising the available level of "lead"
during neap tide by means of sluices, using up the water which forms the upper
"filling" of A. for this purpose, and keeping A. perfectly enclosed continuously.
or
The flow of mud and sand may be arrested or reduced by the means shewn in
Figures 28. and 29, a pocket P. being constructed in the supply channels of such a
capacity as to reduce the velocity of flow of the water to such an extent as not to
displace the sand or mud.
my
Having now particularly described and ascertained the nature of said
invention and the system, mode, or manner, in or under which the same is or may
be used, or practically carried into effect, what I consider to be novel and original,
and therefore claim as the invention secured to me by the hereinbefore in part
recited Letters Patent is :-
(1.) The general arrangement and combination of parts constituting the
improvements in and connected with the utilization of tidal energy, substantially
as hereinbefore described.
(2.) The general arrangement and combination of parts constituting my improved
tidal power house, substantially as hereinbefore described.
(3.) The general arrangement and combination of parts constituting a reservoir,
substantially as herein before described and illustrated on the drawing Figure 16.
(4.) The combination of the balanced valve, (Figure 20) with the valve
seats V. S. as described.
(5.) The combination of the lever or levers L. (Figure 21.) with the tube T.
springs S. and valve, as described.
(6.) The combination of the balanced valve with the appliance for making a water
tight joint, and the sea walls A. and A₁, substantially as herein before described and
illustrated on the drawings, Figures 22. and 23.
(7.) The combination of the two reservoirs A and B. (Figure 26.) substantially
as described, and for the purposes set forth.
(8.) The combination of the two reservoirs A. and B. and the "lead" L.
(Figure 27.), substantially as described and for the purposes set forth.
(9.) The use of the "pocket" P. (Figures 28. and 29.) for arresting the flow
of mud and sand into the reservoir as described.
Dated this 11th day of April 1894.
GEO. C. DOUGLAS & Co.,
41, Reform Street, Dundee, Agents for Applicant.