Patent GB-1193651-A (GB)
Title: Analog Computer for Proportioning the Components of a Batch Mixture.
Inventor: BROSSET NOEL MARIE HENRI
IPC: G06G7/75
Filed: 1966-05-25
Abstract: 1,193,651. Batch mixture calculating; mechanical calculating apparatus. PEDERSHAAB MASKINFABRIK A/S. 22 May, 1967 [25 May, 1966], No. 23383/66. Headings G4B and G4G. [Also in Division G1] For computing concrete mixtures comprising proportions C, W, G of cement, water and gravel three rulers C, W, G (Fig. 3) extending perpendicularly to guides a, b, c constituting an equilateral triangle of variable height M, are slidably connected at an abutment movable along an arm K #  pivoted at apex A and moving over a scale I # . It is shown by geometry that the lengths of the rulers between the abutment and the corresponding guide represent the analogue values of the three components C, W, G of a mixture whose total amount is represented by height M. If the abutment is moved to the triangle base line, the intercepts thereon are (2/#3)C m  and (2/#3)W m , where C m , W m  are the intercepts of the triangle sides on the rulers, so that K f  indicates ratio W/C on scale If as a measure of strength of concrete. In use, K f  is set to desired value f = W/C and the abutment is displaced along arm Kf to read a desired water content as a measure of slump on ruler W 1 , when the desired gravel and cement contents are read on rulers G 1  and C 1 . An electrical equivalent comprises a potentiometer Pg across a voltage supply OM, OMS representing total mixture M with a slider adjustable in accordance with water content connected to terminal MS 2  and energizing potentiometer P #  returned to supply OM. The slider K #  of the latter connected to terminal MS 1  is adjusted in accordance with ratio W/C = f and measuring instruments I c , I W , I G  are connected between terminals OM, MS 1 , MS 2 , OMS. Slider K f  is adjusted to establish the required strength and slider K w  is adjusted to establish the required slump (water content) on instrument I w , after which instruments I c , I G  indicate required quantities of cement and gravel. For computing the ratio of quantities of stone skeleton S 1 , S 2 , S 3  three corresponding rulers are provided perpendicular to the sides of an equilateral triangle (Fig. 4) and are connected at abutment AN where pivotable arms KS 1 , KS 2  intersect, which are angularly adjustable to establish the relationship S 1 /a = S 2 /b = S 3 /C, and the height of the triangle is adjusted to represent e.g. 100 on indicator I st  so that the ratios S 1  S 2  S 3  are expressible as percentages on the ruler scales. The height of the triangle is adjustable thereafter against scale I st  to a value KS 3  representing a ratio g between skeleton and total mixture, and the arms KS 1 , KS 2  are held locked in the adjusted position, so that the actual values of S 1  S 2 , S 3  may be read off the ruler scales. An electrical equivalent comprises potentiometer D 3  energized by voltage S 100  whose slider KS 3  energizes further potentiometer AS whose slider KS 1  energizes third potentiometer BS. The sliders are respectively connected to terminals OMS, OS 1 , OS 2  and meters IS 1  IS 2 , IS 3  are connected in series between these terminals and return line OS 3  while meter I st  is connected between OMS and OS 3 . KS 3  is initially placed at the top of its potentiometer while KS 1 , KS 2  establish proportions a; b; c on meters IS 1 , IS 2 , IS 3  Slider KS 3 , is adjusted to the desired ratio between skeleton and total mixture read on I st , so that the remaining meters indicate quantities of stones S 1 , S 2 , S 3 . When air is entrained in the mixture, the mechanical computing devices of Figs. 3, 4 may be combined base to base; the height of the M triangle of Fig. 3 representing C.W.G. mix, that of the S triangle of Fig. 4 representing the skeleton mix, and the interposed height of a small triangle representing entrained air (Fig. 5, not shown). Postulating the total triangular height as the analogue of the total batch volume, different air contents may be compensated by displacing the base of the M triangle (or the S triangle) according to the percentage of air read mechanically on a scale; or electrically by measuring the output of a correspondingly varied potentiometer (Fig. 5, not shown). Fig. 6 shows a comprehensive mechanical computer wherein stationary rails Ma, Mb; Mal, Ma2 form the sides of opposed equilateral triangles M, S with apieces A 1 , A 2  whose displacement is measurable on scale I t  and adjustable to represent the volume of the total mix. Base rail M c  of the M triangle is displaceable against scale I L  to represent by L the quality of entrained air, and rail Mc 1  is the base of the S triangle displaceable against scale I st  to represent the percentage of store skeleton in the batch. AmKf pivoted at A indicates ratio water to cement on scale If and carries abutment K w  in which are slidable rulers C 1 , W 1 , G 1  perpendicular to the sides of triangle M on which are indicated quantities of cement, water and gravel, while arms KS 1 , KS 2  pivoted at adjacent apices of the base triangle slide through an abutment carrying rulers S 1 , S 2 , S 3  perpendicular to the sides, on which are indicated the proportions of stones S 1 , S 2 , S 3 . KS 3  is initially set to represent a unit amount of skeleton, and arms KS 1 , KS 2  are angled until the desired percentages of stores of different sizes are read off on rulers S 1 ,S 2 , S 3  after which the arms are locked. KS 3  then reset to represent the percentage of skeleton in the total mix on scale I st , and M c  is displaced for the percentage of entrained air to be read on scale I L  AmKf is adjusted to indicate ratio of water to cement on scale If, and abutment KW is displaced until the required amount of water is read on scale L L , and the remaining analogue values of components of the mixture are read out of the system, since it is shown that:- 1. S 1 : S 2 : S 3 =a:b:c  2. (S 1  + S 2  + S 3 ): (L + C + W + G + S 1  + S 2  + S 3 ) = d 3. L: (L + C + W + G + S 1  + S 2  + S 3 )= e  4. W:C=# 5. (W  +  C): (W  +  C  +  G) = g 6. L+C+W+G+8 1 +8 3 +8 3 = unity batch of e.g. 1000 litres, where d = ratio paste/skeleton L = entrained air e = ratio entrained air/total mix g = ratio cement + water/cement + water + gravel ' The mechanical indications may be converted to electrical indications by operation of variable potentiometers. An electrical equivalent (Fig. 7) comprises a voltage source VS controlled by variable series resistor OP to a value between IT i , ITg representing equation (6) read on meter I t , which energizes potentiometer D 1  adjusted to the proportion of entrained air read as voltage analogue on meter I 2  between outputs OM and OL according to equation (3). A further potentiometer D 3  across I t1 , I t2  develops a voltage S read by meter I st  between outputs OMS, OS 3  representing the amount of skeleton, and a voltage M between outputs OM, OMS represents the amount of mortar M comprising cement C, water W, and gravel G. Potentiometers A s , B s  develop proportional voltages read on meters I 81 , I 82 , I 83  between outputs OMS, OS 1  OS 2 , OS 3  representing the components S 1 , S 2 , S 3  of the skeleton, and potentiometers Pg, P #  between sliders of potentiometers D 1  and D 3  develop proportional voltages read on meters I c , I w , Ig between outputs OM 1 , MS 1 , MS 2 , OMS representing the components C, W, G of the mortar. Manually operated switch SW connects IT 1  to the slider of D 3 , and a differential ratio meter (not shown) whose coils are energized between MS 1  and OM MS 2  respectively reads the ratio W/C. In operation, switch S w  is closed for skeleton adjustment and the potentiometer AS is adjusted for meter IS 1  to indicate the required percentage of stones S 1  after which potentiometer B s  is adjusted for meter IS2 to indicate the required percentage of stones S 2 . Meter IS 3  then automatically reads the required percentage of stones S 3 . Switch SW is opened, and potentiometer D 3  is adjusted for meter I st  to indicate the percentage skeleton in the entire batch. Potentiometer D 1  is adjusted to represent the entrained air, and the remaining voltage between outputs OM and OMS represents the mixture of cement, water and gravel. Potentiometer K #  is adjusted to read a required water/cement ratio W/C established by the desired concrete strength on ratiometer If, and potentiometer Pg is adjusted until the water content W set by the desired slump is read on meter I w , so that meters I c , I G  indicate the required amounts C, G of cement and gravel. The indications are also represented by the corresponding output analogue voltages. Optional potentiometer P KW  between outputs OMS and MS 2  may be set the water content of the gravel, and its slider output is multiplied in DA by the output of potentiometer P g  and applied to output MS 2  in lieu of the connection to the slider of Pg. The total analogue voltage (W + G) is therefore divided to increase the G component by the gravel water content and to decrease the W component by the same amount. A correcting electronic servomultiplier may be controlled continuously by gravel water content measuring equipment. The output voltages representing the required quantities of the components of the concrete mix may be displayed digitally by repeater indicators in the mixing plant, or may control servosystems programmed to operate in sequence to automatically regulate the quantities of the components dispersed. In a cement dispenser (Fig. 8) a silo 50 has closure 52 partially controlled by member 56 and completely controlled by member 54 to release material into weighing bucket 60 and scale 62. Voltage source BW energizes potentiometer P wg  adjusted by the weighing device to produce a weight voltage applied to a differential amplifier OA together with a feedback voltage from multiplier potentiometer P oa  energized from the error voltage between the amplifier output and the weight control voltage