US1799113A - Safety and stopping arrangement for intermittently-operating apparatus - Google Patents

Description

March 31, 1931.

C. MIEDBRODT SAFETY AND STOPPING ARRANGEMENT FOR INTERMITTENTLY OPERATING APPARATUS Filed Sept. 11, 1929 I I I Patented Mar. 31, 1931 UNITED STATES PATENT OFFICE SAFETY AND STOPPING ARRANGEMENT FOR INTERMITTENTLY-OPEATING APPARATUS Application filed September 11, 1929, Serial No. 391,947, and in Germany March 31, 1928.

In the case of intermittently operating ap-' paratus (such as gas producers) their closure members (such as slides, valves, clack valves and cocks) to be controlled are frequently opened and closed by lifting cylinders operated by a pressure medium (such as water, oil, air or steam). The lifting cylinders served by the control members are actuated from a centre, the control being either auto- 1 matic by suitable driving means (such as an electromotor) through a control shaft set in rotation thereby, or also by hand.

In intermittent apparatus of this kind, the

several closure members must be actuated in a definite serial order and at definite inter vals, and it is also necessary that each lifting cylinder, when connected up by means of the control member, should perform its function in an orderly manner, that is to say, at the proper time and for the prescribed eriod. p In the known arrangements employed, for example, in the case of gas producers, failure of the closure members to maintain orderly movement can give rise to great danger, for example through explosions. Care must therefore be taken that not only can any failure in the working mechanism of the control members be rendered apparent, but also that the entire apparatus can be brought to a standstill at once.

In the case of automatically controlled intermittenly operating apparatus, the present invention provides that, in the event of the several closure members failing to operate in an orderly manner, the actuation of the several control members, and also of the entire apparatus, is interrupted at once. In addition, the attention of the attendant is drawn to the fact that the apparatus is out of order, by means of an optical and acoustic signal.

The fundamental idea of the invention consists in that, in the event of irregular action on the part of one of the lifting cylin dens serving the closure members, the resulting omission to complete the excitation circult of a time switch provided for such lifting cylinder causes the breaking of the circuit of the electromotor actuating the control member, after the interval for which the time switch is set has elapsed. -The arrangement is also such that, on said circuit becoming dead, a release device therein reverses the direction of the pressure medium in such a Way that the pressure medium (whether oil, air or the like) exerts on all the control mem bers a pressure adapted to put the closure devices of the apparatus out of operation. The result is that, in addition to drawing attention to the fact that the one cylinder is not operating in an orderly manner, the entire apparatus is automatically brought to a standstill. The energizing action of the time switch ceases during the period in which the control member and the piston in the lifting cylinder perform their movements during the interval prescribed for this opera tion. If, however, the interval prescribed for the operation is exceeded, the circuit of the electromotor is broken in consequence of the unduly prolonged inaction of the energizing action of the time switch. At the same time provision is made whereby the movement of the lever interrupting the current completes another circuit containing a signal lamp for each time switch, which lamp is then lighted. Consequently, the attendant can see at once which of the closure members has failed. In order, however, to guard against failure on the part of the attendant to notice the optical signal, there is also included in the same circuit an acoustic signal, which always sounds when any of the signal lamps lights.

A typical embodiment of the invention is illustrated diagrammatically on the accompanying drawing to which reference will now be made.

The closure members 1, disposed for example on a gas producer, are actuated by pistons 4 working in lifting cylinders 2 under the action of a pressure medium 3. The serial order of operation and timing of these pistons are controlled by their allotted control members 5, to which motion is imparted by cams 7, driven by an electromotor 6 and acting through crank levers 8. In the circuit 9 of the electromotor, a number of interruptor levers 10, (equal to the number of lifting cylinders) are disposed in series. According to the invention and for assuring the safety of the apparatus, each interruptor lever is provided with a time switch 11 so adjusted as not to come into operation until after the time has elapsed at which the operation initiated by the lifting cylinder is to be performed,'that is to say, either when the lifting cylinder has not performed its operation at all, or else has not completed it. The circuit including the exciting coil of the time switch 11, and limit switches or contacts 12, 13 provided on the corresponding control member and on the rod of the coacting piston 4, constitute an auxiliary circuit in parallel with the main or motor circuit 9, and the arrangement is such that during the normal operation, each time the movement of the piston (and with it the coacting control member) is reversed, the saidauxiliary circuit is completed through the contacts 12, 13, the result being that the release 14 of the time switch cannot exert any action on the corresponding interruptor lever 10 of the circuit 9. If (as shown in the case of the lifting cylinder on the right in the drawing) a piston 4: stops through any cause and the time prescribed for the release of the corresponding time switch 11 expires, then its release 14 acts by pressing down the appropriate interruptor lever 10, thereby breaking the circuit 9 and bringing the electromotor and the cam 7 to a standstill. In order, in such. case, 'to prevent any further action of the operations initiated by the other lifting cylinders, provision is made for reversing the direction of flow of the pressure medium by means of a device 15, which is released when the supply of current to the electromotor ceases and operates a two-way cock 16, so that the pressure medium 3 then exerts on all the control members 5 a pressure which sets all the closure members 1, in a position corresponding to the stoppage of the whole apparatus 11 order that the attention of the operative may be directed to the stoppage which has occurred, it is arranged that, simultaneously with the breaking of the circuit 9 by any of the interruptor levers 10, another clrcuit 17 is completed in which there is provided, for each tlme switch, a signal lamp 18 which thereupon lights. There is also provided in the same circuit an acoustic signal 19 which sounds every time any of the signal lamps 18 in the circuit is lighted.

It will be understood that the described safety device can also be suitably applied to controls in which the control members 5 are manually operated. In such case the stoppage of the electromotor and the reversing of the pressure medium by the time switch is dispensed with.

I claim 1. A safety stopping arrangement for intermittently operating apparatus, comprising in combination, at least one fluid actuated piston for actuating the operating parts of said apparatus, at least one piston valve for controlling the flow of the fluid to said pistons, at least one rotary cam device for actuating said control valves to stop said pistons, an electric motor for driving said rotary cam device, a time switch adapted to cut out said electric motor and therefore the drive on said cam device controls when the operation of any of the intermittently operating parts ceases, and a secondary control device adapted to be operated when said electric motor is cut out, to actuate said piston valves to stop the whole apparatus.

2. A safety stopping arrangement for intermittently reciprocative, apparatus, comprising in combination, fluid actuated pistons for reciprocating said apparatus, fluid actuated piston valves for controlling the flow of the fluid to said pistons, rotary cam devices for controlling the operation of said piston valves, at least one electric motor for driving said rotary cam devices and electric time switches adapted, on the operation of the intermittently reciprocative apparatus becoming abnormal, to bring into operation means which cut out said electric motor, give a warning signal and control the supply of fluid to the piston valves, causing them to take positions which cause the operation of the fluid actuated pistons and therefore of the reciprocative apparatus to cease.

3. A safety stopping arrangement for intermittently reciprocative apparatus, comprising in combination, fluid actuated pistons for reciprocating said apparatus, fluid actuated piston valves for controlling the flow of the fluid to said pistons, rotary cam devices for controlling the operation of said piston valves, at least one electric motor for driving said rotary cam devices, pairs of contacts one of each pair carried by one of said fluid actuated pistons and the other of each pair carried by one of said piston valves, each of said pairs, of contacts being adapted to coact together normally to keep the electric circuit of said electric motor closed, but also adapted, when the operation of any of the intermittently reciprocative parts ecomes abnormal to open the circuit of said electric motor to give audible and visual signals and to stop the operation of the intermittently reciprocative apparatus.

4. A safety stopping arrangement for intermittently reciprocative apparatus, comprising in combination, fluid actuated istons for reciprocating said apparatus, uid actuated piston valves for controlling the flow of the fluid to said pistons, rotary cam devices for controlling the operation of said piston valves, at least one electric motor for driving said rotary cam devices, pairs of contacts one of each pair carried by one of said fluid actuated pistons and the other of each pair carried by one of said iston valves each of said pairs of contacts eing adapted to coact together normally to keep the electric circuit of said electric motor closed, but also adapted, when the operation of any of the intermittently reciprocative arts -becomes abnormal to open the circuit of said electric motor, simultaneously com leting another circuit containing for eacfl time switch, a signal lamp which thereupon lights up, and the opening of said motor circuit also actuating a two-way valve which caused the fluid to actuate the said piston valves and to stop the operation of the intermittently reciprocative apparatus.

5. A safety stopping arrangement for intermittently .reciprocative apparatus, comprising in combination, fluid actuated pistons for reciprocating said apparatus, fluid actuated piston valves for controlling the flow of the fluid to said pistons, rotary cam devices for controlling the operation of said piston valves, at least one electric motor for driving said rotary cam devices, pairs of contacts one of each pair carried by one of said fluid actuated pistons and the other of each pair carried by one of said piston valves, each of said pairs of contacts being adapted to coact together normally to keep the electric circuit of said electric motor closed, but also adapted, when the operation of any of the intermittently reciprocative parts becomes abnormal to open the circuit of said electric motor, simultaneously completing another circuit containing for each time switch, a signal lamp which thereupon lights up, and an acoustic signal which thereupon sounds, and the opening of said motor circuit also actuating a two-way valve which causes the fluid to actuate the said piston valves and to stop the operation of the intermittently reoiprocative apparatus.

In testimony whereof I aflix my signature.

CARL MI'EDBRO-DT.

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