Patent GB-633759-A (GB)
Title: Improvements in or relating to automatic control means for gas making and similar cyclically operated apparatus
IPC: C10J3/24
Filed: 1945-09-08
Abstract: 633,759. Water gas plant. POWER-GAS CORPORATION, Ltd., WRIGHT, G., and HOLMES, F. R. Sept. 8, 1945, No. 23184. [Class 55 (i)] [Also in Group XXIX] Apparatus for automatically controlling the timing and sequence of valve operations in the cyclic process of a water gas plant, has a master timer which effects step-by-step displacements of a segmental circuit selector at variable predetermined time intervals, which circuit selector energizes in succession groups of selectors controlling the subsequent operation of the valves, each group of selectors preselecting a combination of valve positions for each respective phase in the cyclic process of the plant. A master timing disc a, Fig. 1, is driven through gearing b by a synchronous motor c and executes one revolution in a period which bears a simple numerical relation to the time of a complete cycle of the plant, e.g. one to one. The disc a may also be driven rapidly to a shut-down position by a motor g through gearing of more direct ratio. Pegs a1, a2 ... a10 corresponding in number to the product of the number of valves and the number of positions in which each valve can be set are placed in selected holes spaced round the periphery of the disc a so that the timing of each phase in the cycle may be adjusted by adjustment of the pegs in the holes. The pegs successively operate a star wheel d geared to a cam e which actuates a switch arm f. The wheel d has eight spokes and the cam e. four sides so that alternate pegs a1, a2 &c. connect contacts f1, f3 or f1, f2. The contacts f2, f3 are connected to the windings of and alternately control the energization of relays r, s, Fig. 3. The movable contactors of the latter are electrically connected to two alternately arranged sets of contacts jlX, j3X, j5X, j7X, j9X and j2X, j4X, j6X, j8X, j10X, Fig. 2 on a circuit selector having a rotary brush bar k driven by a step-by-step motor m. The circuit selector j carries also an annular contact jZ, two arcuate contacts j1Y, j2Y one extending over a much larger one than the other, and five annular sets of arcuate contacts j1A, j2A ... jlOA ; j1B, j2B ... j10B; j1C, j2C ... j10C; j1D, j2D ... j10D and j1E, j2E ... j10E. Each contact of each set is connected to the movable contact of a corresponding two way switch of which there are five sets of ten namely 01A, 02A .. OIOA; 01B, 02B ... OIOB; 01C, 02C ... 010C, 01D, 02D ... 010D; and 01E, 02E ... OlOE, corresponding to the change-over valve, the steam valve, the stack valve, the secondary air valve, and the primary air valve respectively of a water gas plant Each of the fifty switches as shown in Fig. 5 comprises also two fixed contacts with either of which the movable contact may be selectively engaged. The right hand fixed contacts of each set are electrically connected together and to a relay such as u controlling the energization of an electromagnetically - operated hydraulic control valve such as w in turn controlling the opening of the main valve appropriate to the set of switches, in this case the primary air valve z. The left hand fixed contacts of each set of switches are likewise connected to one another and to circuits for indicating, interlocking and alarm purposes. The brush bar K, Figs. 2, 3, carries eight brushes K1, K2 ... K8, electrically connected and thus during each phase of the cycle contacts a group of arcuate contacts such as j1A, j1B, jlC, j1D, j1E, the switches 01A, 01B, 01C, 01D, 01E corresponding to which form a group containing one for each of the main operating valves. When the brush bar K reaches a particular group of contacts, the valves of which are engaged by the appropriate movable contact the corresponding right hand fixed contacts are opened if not already open and correspondingly the valves of which the left hand fixed contacts are engaged by the appropriate movable contact are closed if not already closed. The simplified circuit diagram shown in Fig. 3 in which the alarm indicator and interlock circuits are omitted and in which only the set of switches 01E, 02E ... 010E pertaining to the primary air valve are shown comprises also an emergency relay p, a manual starter switch q, a relay t controlling the operation of the step-by-step motor m and an electromagnetic brake n associated therewith, and a two-way switch h1, h2, h3 operated by a cam ax, Fig. 1, on the timing dial when the latter reaches the "shut-down" or starting position. If the starter switch is operated with the timing dial a in the "shut-down" position, the contacts q1, q2 are closed and contacts q3, q4 opened and if the stop switch 15, 16 is also closed and the hydraulic line pressure is holding contacts 13, 14 closed the emergency relay p is energized one terminal p2 being connected to the supply line 12 and the other terminal p, being connected to the return line 11 through contacts 13, 14, 15, 16, q2, q1, h2, h1, p7, p8, j2Y, Fig. 3, brush K2, brush bar K, brush K1 and contact jZ. After the starter switch q is released, a holding circuit is formed through contacts p3, p4 with the line 11. The same action also energizes the motor c through the line 11, contacts p6, p5, q4, q3, terminals c1, c2 to line 12. The disc a therefore starts its timed cycle and when the next peg a2 engages the star wheel d, the switch arm f is operated to energize one of the relays r, s and de-energize the other one. The effect of this is to disconnect the terminal t1 of the relay t from the five connected contacts j2X, j4X, j6X, j8X, j10X by opening contacts s3, s4 and to connect said terminal with the alternate contacts j1X, j3X, j5X, j7X, j9X by closing contacts r3, r4. The motor m is therefore started and the brake n simultaneously released so that the brush bar K sweeps the contacts of the circuit selector until the brush K3 leaves the contact j1X and the brush bar comes to rest with the brushes K4 ... K8 on the next group of contacts j2A, j2B, j2C, j2D, j2E at which time the relay t is de-energized, the motor m stopped, and the brake n applied.. The timer disc a continues to rotate and eventually the next peg a3 causes the arm f to be changed is again reversed and the motor m is energized through the relay t, contacts s3, s4, j2X, brushes K3, K1 and contact jZ. The motor m continues in operation with the brake n released until the brush K3 leaves the contact j2X. Similar circuit operations occur for each phase until the cycle is completed. If at any stage the fluid pressure should fail and open contacts 13, 14 or the stop switch 15, 16 should be opened, the relay p becomes de-energized and due to the closing of contacts p9, p10 and p7, p8 the relay t is energized, the motor m rotates the brush bar K until it stops in the vertical position, and the motor g is started. The motor c stops due to contacts p5, p6 being opened. The disc a stops in the shut-down position shown in Fig. 3 when the cam a<SP>x</SP> opens the contacts h1, h3. Fig. 6 shows an indicating, interlocking circuit, with provision for hand control for the primary air valve. The right hand fixed contacts of all the switches 01E ... 010E are connected to contact 19 whilst the corresponding left hand fixed contacts are connected to contact 22. Contacts 19, 20 and 22, 23 are closed by an " automatic-hand " change-over switch for automatic operation. If the contact 19 is energized by one of the switches 01E ... 010E, the primary air valve opening relay winding u1, u2 can only be energized if five conditions hold namely (1) contacts 31, 32 are closed due to the change-over valve opening relay being deenergized, (2) contacts 33, 34 are closed due to the change-over valve interlock relay being energized, (3) contacts 41, 42 are closed due to the purge valve being closed, (4) contacts 43, 44 are closed due to the purge valve having been closed for a predetermined time, and (5) contacts p11, p12 are closed due to the emergency relay p remaining energized. When these conditions hold the primary air valve opens and in the fully open position a limit switch 29, 30 closes the circuit to an indicating lamp B. Simultaneously the primary air valve interlock relay 39, 40 is energized since the contacts u5, u6 are closed by the relay u. When the movable contact of the pertinent selector switch is in the left hand position the relay u is not energized and a limit switch 35, 36 completes a circuit to a lamp C and also another circuit through contacts u7, u8 to the primary air valve interlock relay 39, 40. The contacts u7, u8 are closed when the relay u is not energized. For hand operation the change-over switch is moved to open contacts 19, 20 and 22, 23 and close contacts 20, 21 ; 23, 24 ; 25, 26 ; and 27, 28. The two latter short-circuit contacts 41, 42 ; 43, 44 ; and p11, p12 so that manual operation is independent of the condition of the purge valve or the relay p. To open the primary air valve, a push button is depressed to close contacts A1, A2 and open contacts A3, A4. The relay u. will be energized if the first two only of the above five conditions hold. When the valve is fully open, the lamp B is illuminated and the interlock relay 39, 40 is energized. If a second push button is depressed, contacts A1, A2 are opened and contacts A3, A4 are closed. The relay u is then de-energized and when the primary air valve reaches the fully closed position the lamp C lights and the relay 39, 40 is energized. Various other interlocking arrangements are referred to. Fig. 7 shows an alarm circuit designed for use with hand or automatic operation. Contacts 49, 50 are closed for automatic operation. If the emergency relay p becomes de-energized, contacts p15, p16 and p13, p14 close so that the lamp E is illuminated and an alarm relay 55, 56 is energized. The latter closes a switch 59, 60 to an alarm bell D and a switch 53, 54 which completes a holding circuit to the relay 55, 56 so that the alarm keeps on ringing until a push switch 51, 52 is opened. Similarly switches 57