Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/16—Controlling or regulating processes or operations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/12—Accessories for subsequent treating or working cast stock in situ
  • B22D11/128—Accessories for subsequent treating or working cast stock in situ for removing

Definitions

• the invention relates to a device for the hydraulic adjustment of components, in particular the rollers of strand guide segments of a continuous casting installation, with hydraulic cylinders which are each divided into a cylinder space and an annular cylinder space by a piston with a piston rod, the cylinder spaces being alternately and in opposite directions by control elements and simultaneously with one Pressure source and a pressure sink are connectable.
• the casting process begins in a mold. From this, the surface solidified cast strand emerges vertically and is deflected by 90 ° in strand guide segments with a certain radius and directed to a subsequent horizontally arranged straightening driver.
• the cast strand is guided by means of guide rollers which can be adjusted by hydraulic cylinders. This means, among other things, roller wear and changed casting parameters can be taken into account.
• Continuous valves are generally used to control the hydraulic cylinders; due to their exact fits, these require finely filtered hydraulic oil. The effort associated with oil filtering is considerable. In addition, there is always a fire hazard with hydraulic oil in the casting machine and rolling mill area.
• the invention has for its object to provide a hydraulic system for adjusting strand guide segments, which has a comparatively low demand on the cleanliness of the operating fluid and a low fire risk.
• switching valves are provided as control elements. Switching valves are either closed or open, while continuous valves can also take any intermediate position. That is why switching valves tolerate coarse dirt particles without clogging, while the possible gap opening of a continuous valve depends on clean working medium is to prevent seat contamination.
• the valve pistons of the switching valves do not require a tight fit, since they center themselves at the stop when open and in the seat when closed. This also means that the requirements for cleanliness and, in addition, for the lubricity of the working fluid are significantly lower for switching valves than for continuous valves. This means less filtering effort and the trouble-free use of water oil emulsions as working fluids.
• fire safety is a decisive advantage of the solution according to the invention.
• the arrangement of four switching valves in a full-bridge circuit ensures simple routing and a short length of the hydraulic lines with a correspondingly low installation effort.
• the switching valves can be controlled via a three-point controller.
• the three-point controller only works with the plus, minus and zero positions. At plus, one switching valve pair is energized, at minus the other, while at zero both switching valve pairs are de-energized and therefore closed. This results in a simple controller structure.
• the switching valves can be controlled via pulse width modulation. While the opening time interval of the switching valves as a whole is varied in the three-point control, the number of constant, short opening intervals is variable in the pulse width modulation (variable duty cycle). Similar to the three-point controller, this is done using discrete switching signals from separate electronics hardware or using software from a computer. This optimizes the duty cycle in the direction of switching frequency reduction. With pulse width modulation As with the three-point control, an exhaust and intake switching valve are always controlled at the same time, since the inflow volume of one cylinder space always corresponds to the same outflow volume of the other.
• each piston is connected via a connecting rod to a position transmitter, which triggers the control after an upper or lower limit value of the piston position has been exceeded.
• the position sensors enable a closed control loop for the piston position. Determining a hysteresis of the permissible piston position by means of an upper and lower limit value results in a simple structure and simple commissioning of the three-point controller.
• 1 is a circuit diagram of the bridge circuit of the hydraulic oil circuit of a hydraulic cylinder
• FIG. 2 is a circuit diagram of the hydraulic oil circuit and the control of the switching valves of a hydraulic cylinder
• Fig. 3 is a simplified circuit diagram of the hydraulic oil circuit
• FIG. 1 shows the switching valves (1a, b, c, d) of the hydraulic circuit of a hydraulic cylinder (2) connected together in a bridge circuit, which are combined to form a valve block (3).
• the switching valves (1a, b) can be connected to a pressure sink (5) via a first connection point (4), the switching valves (1c, d) can be connected to a pressure source (7) via a second connection point (6).
• the switching valves (1 a, c) are also connected via a third connection point (8) to a cylinder chamber (9), the switching valves (Ib, d) via a fourth connection point (10) to an annular cylinder chamber (11) of the hydraulic cylinder (2) .
• the cylinder chamber (9) and the ring cylinder chamber (11) are sealingly divided by a piston (12) which has a piston rod (13) emerging from the ring cylinder chamber (11). 1 shows the very compact arrangement of the valve block (3) which is implemented with little wiring.
• FIG. 2 shows a valve block with a hydraulic cylinder (2) and a simplified representation of the electrical control of the switching valves (1 a, b, c, d).
• Fig. 2 also shows the connection points (4, 6, 8, 10) for connecting the switching valves (la, b, c, d) with the pressure sink (5) and the pressure source (7), the cylinder chamber (9) and the ring cylinder chamber (11).
• the piston (12) is connected by a connecting rod (14) to a position transmitter (15) which indicates the respective position of the piston (12) in relation to the hydraulic cylinder (2).
• the switching valves (1a, b, c, d) each have an electromagnet (16) which is connected to a three-point controller (18) or a pulse width modulator (19) via electrical lines (17a, b, c, d).
• Three-point controller (18) and pulse width modulator (19) are implemented as electronic hardware or integrated as software in a computer (20).
• the switching valves (1a, b, c, d) have springs (21) which they shoot when the electromagnets (16) are de-energized.
• the piston rods (13) are sealed by glands (22), which also serve to support the hydraulic cylinders (2) on one half of the strand guide segments (35, Fig. 4). They carry at their free end an articulated head (23) for connecting it to the other half of the strand guide segments (35).
• Figure 3 shows a simplified circuit diagram of the hydraulic oil circuit and the control of the valve blocks (3) for the four hydraulic cylinders (2) of a strand guide segment (35, Fig. 4). Straighteners and saws can also be operated in the same way.
• a control cabinet (24) is connected to a computer (25), the software of which controls the switching valve blocks (3) by means of three-point controllers or pulse width modulation.
• the control cabinet (24) has, inter alia, a network card (26), a central processor unit (CPU) (27), a memory (28), an interface (29), for example an SSI interface for connection to the position sensors (15 )., A digital / analog converter or switching amplifier (30) for the switching valve signals, a digital input / output (31) for a control panel (32) on site and for a terminal block (33) for connecting the system signals; there is also a power supply (34).
• Figure 4 basically shows the same as Fig. 3, but with a strand guide segment (35) in perspective.
• This has rollers (36), between which the cast strand (37) to be guided is located and which have supports (38).
• the latter are activated by the hydraulic cylinders (2) and by the pistons (12) by means of the piston rod (13).
• Pressure transmitters (39) are installed in the hydraulic lines between the switching valve blocks (3) and the hydraulic cylinders (2) to monitor the process. Your signals are collected together with those of the switching valve block (3) in an input / output module (40) and passed on to the digital / analog converter (30).
• the signals from the position sensors (15) are routed to the interface (29).
• the system according to the invention functions as follows: If the position sensors (15) indicate a deviation of the desired position of the rollers (36), three-point control or, after a certain upper or lower limit value is exceeded Pulse width modulation restores the target position by actuating the corresponding switching valves (1a, b, c, d).
• a water-oil emulsion can be used as the working fluid, which significantly reduces the risk of fire in the event of leakage.
• there is no need for ultra-fine filtering of the working fluid as a result of which the system according to the invention is cheaper to buy and operate.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Fluid-Pressure Circuits (AREA)
• Continuous Casting (AREA)
• Rotary Presses (AREA)
• Servomotors (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=7877508

Family Applications (1)

Country Status (16)

Cited By (1)

Families Citing this family (15)

Family Cites Families (9)

• 1998
  • 1998-08-14 DE DE19836843A patent/DE19836843A1/de not_active Withdrawn
• 1999
  • 1999-08-12 TW TW088113777A patent/TW418133B/zh not_active IP Right Cessation
  • 1999-08-13 CA CA002340351A patent/CA2340351C/fr not_active Expired - Fee Related
  • 1999-08-13 DE DE59907218T patent/DE59907218D1/de not_active Revoked
  • 1999-08-13 KR KR1020017001797A patent/KR100593720B1/ko not_active IP Right Cessation
  • 1999-08-13 AT AT99944388T patent/ATE250997T1/de not_active IP Right Cessation
  • 1999-08-13 RU RU2001106988/02A patent/RU2226448C2/ru not_active IP Right Cessation
  • 1999-08-13 TR TR2001/00466T patent/TR200100466T2/xx unknown
  • 1999-08-13 CN CNB998096547A patent/CN1329145C/zh not_active Expired - Fee Related
  • 1999-08-13 US US09/762,514 patent/US6540010B1/en not_active Expired - Fee Related
  • 1999-08-13 WO PCT/EP1999/005944 patent/WO2000009279A1/fr not_active Application Discontinuation
  • 1999-08-13 JP JP2000564762A patent/JP2002522231A/ja active Pending
  • 1999-08-13 ES ES99944388T patent/ES2209494T3/es not_active Expired - Lifetime
  • 1999-08-13 UA UA2001031705A patent/UA73723C2/uk unknown
  • 1999-08-13 ID IDW20010561A patent/ID28771A/id unknown
  • 1999-08-13 EP EP99944388A patent/EP1105235B1/fr not_active Revoked
  • 1999-08-13 BR BR9912898-5A patent/BR9912898A/pt not_active IP Right Cessation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events