Conjugated protection device for furnace door driving cylinder

Abstract

The utility model relates to a conjugate protection device for a furnace door driving cylinder, which comprises a cylinder, a four-position five-way reversing valve, a first pilot check valve and a second pilot check valve, the four-position five-way reversing valve is provided with a first air outlet and a second air outlet, the first air outlet is connected with a rodless cavity of the cylinder through the first pilot check valve, and the second air outlet is connected with the rodless cavity of the cylinder through the second pilot check valve. The second air outlet is connected with a rod cavity of the air cylinder through a second pilot check valve, the first air outlet is provided with a first branch connected with a pilot port of the second pilot check valve, and the second air outlet is provided with a second branch communicated with a pilot port of the first pilot check valve. When the first air outlet and the second air outlet lose pressure, the first pilot check valve and the second pilot check valve are equivalent to one-way valves for preventing air from leaving the air cylinder, so that a piston of the air cylinder cannot move at the moment, and a furnace door can be stopped in a state before pressure loss in a use occasion, so that the air cylinder is prevented from moving. And quenching oil steam is prevented from flowing into the carburizing chamber due to looseness of the furnace door.

Description

Technical Field

[0001] The utility model relates to the technical field of lifting devices, in particular to a conjugate protection device for a furnace door driving cylinder. Background Art

[0002] In a multi-purpose vacuum furnace, doors are located inside the furnace body, separating the carburizing chamber from the quenching chamber. These doors are actuated by a mechanical device, such as a cylinder. The carburizing chamber operates at low pressure, allowing carbon-containing gases to enter the chamber, causing carburization of the treated material. The quenching chamber, however, contains quenching oil, which is at a higher pressure than the carburizing chamber and contains quenching oil vapor. If the cylinder loses pressure while the furnace door is closing, the door will not remain in place. Quenching oil vapor will enter the carburizing chamber, impairing the purity of the carburizing environment and potentially causing product quality issues.

[0003] Japanese patent JPWO2019188127A1 discloses a cylinder fluid circuit, which is used to shorten the time required for the cylinder to return, but does not prevent the furnace door from loosening when the cylinder loses pressure.

[0004] Therefore, it is necessary to improve the structure of the furnace door switch to solve the above problems. Summary of the Invention

[0005] The main purpose of the utility model is to provide a conjugate protection device for a furnace door driving cylinder, which can stop the piston position of the cylinder when the pressure is lost, thereby preventing the furnace door from loosening and causing gas leakage.

[0006] The utility model achieves the above-mentioned purpose through the following technical scheme: a conjugate protection device for a furnace door driving cylinder, comprising a cylinder, a four-position five-way reversing valve, a first pilot check valve and a second pilot check valve, the four-position five-way reversing valve having a first air outlet and a second air outlet, the first air outlet being connected to the rodless cavity of the cylinder through the first pilot check valve, the second air outlet being connected to the rod cavity of the cylinder through the second pilot check valve, the first air outlet being provided with a first branch connected to the pilot port of the second pilot check valve, the second air outlet being provided with a second branch connected to the pilot port of the first pilot check valve, when the first air outlet loses pressure, the gas can only flow one-way from the first air outlet to the rodless cavity, and when the second air outlet loses pressure, the gas can only flow one-way from the second air outlet to the rod cavity.

[0007] Specifically, a first one-way throttle valve is provided between the first air outlet and the inlet of the first pilot check valve, and a second one-way throttle valve is provided between the second air outlet and the inlet of the second pilot check valve. The first one-way throttle valve and the second one-way throttle valve respectively limit the maximum flow rate of the two-way flow of gas.

[0008] Specifically, the rodless cavity outlet of the cylinder is provided with a first manual exhaust device, and the rod cavity outlet of the cylinder is provided with a second manual exhaust device.

[0009] Specifically, a fixing seat is provided on the outer wall of the cylinder, and the four-position five-way reversing valve is fixed on the fixing seat.

[0010] The beneficial effects of the technical solution of this utility model are:

[0011] The utility model has a conjugate structure. When the conjugate protection device is in normal working condition, the pilot ports of the first pilot check valve and the second pilot check valve have air pressure higher than normal pressure, so at this time both are equivalent to ordinary pipes allowing two-way flow; and when the first air outlet and the second air outlet both lose pressure, the first pilot check valve and the second pilot check valve are equivalent to one-way valves that prevent gas from leaving the cylinder, so at this time the piston of the cylinder will not move, then for the use occasion, the furnace door will stop in the state before the pressure loss, avoiding the furnace door from loosening and causing the quenching oil vapor to flow into the carburizing chamber, avoiding the product quality being affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A perspective view of a conjugate protection device according to an embodiment;

[0013] Figure 2 This is a piping diagram of a conjugate protection device according to an embodiment;

[0014] Figure 3 This is a diagram of the usage status of the conjugate protection device of the embodiment.

[0015] The numbers in the figure represent:

[0016] 1-conjugate protection device, 11-cylinder, 12-four-position five-way reversing valve, 12a-first air outlet, 12b-second air outlet, 13a-first pilot check valve, 13b-second pilot check valve, 14a-first one-way throttle valve, 14b-second one-way throttle valve, 15a-first manual exhaust device, 15b-second manual exhaust device, 16-fixed seat, 17a-first branch, 17b-second branch;

[0017] 2-furnace body;

[0018] 3-Furnace door. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below with reference to specific embodiments.

[0020] Example:

[0021] like Figures 1 to 3As shown, the conjugate protection device 1 for the furnace door driving cylinder of the utility model is used to control the opening between the furnace door 3 and the furnace body 2, including a cylinder 11, a four-position five-way reversing valve 12, a first pilot check valve 13a, a second pilot check valve 13b, a first one-way throttle valve 14a, a second one-way throttle valve 14b, a first manual exhaust device 15a and a second manual exhaust device 15b.

[0022] The furnace door 3 is arranged inside the furnace body 2, and the free end of the furnace door 3 is connected to the edge of the furnace body 2 by a conjugate protection device 1. When the conjugate protection device 1 is shortened, the furnace door 3 is closed; when the conjugate protection device 1 is extended, the furnace door 3 is opened.

[0023] like Figure 1 and Figure 2 As shown, the four-position five-way reversing valve 12 has a first air outlet 12a and a second air outlet 12b. The first air outlet 12a is connected to the rodless chamber of the cylinder 11 through a first pilot check valve 13a, and the second air outlet 12b is connected to the rod chamber of the cylinder 11 through a second pilot check valve 13b. The first air outlet 12a is provided with a first branch 17a connected to the pilot port of the second pilot check valve 13b, and the second air outlet 12b is provided with a second branch 17b connected to the pilot port of the first pilot check valve 13a. When the first air outlet 12a loses pressure, the gas can only flow from the first air outlet 12a to the rodless chamber in one direction. When the second air outlet 12b loses pressure, the gas can only flow from the second air outlet 12b to the rod chamber in one direction.

[0024] The above connection structure is a conjugate relationship. When the conjugate protection device 1 is in normal working condition, the pilot ports of the first pilot check valve 13a and the second pilot check valve 13b have air pressure higher than normal pressure, so at this time both are equivalent to ordinary pipes that allow two-way flow; and when the first air outlet 12a and the second air outlet 12b both lose pressure, the first pilot check valve 13a and the second pilot check valve 13b will be equivalent to one-way valves that prevent gas from leaving the cylinder 11, so at this time the piston of the cylinder 11 will not move, then for the use occasion, the furnace door 3 will stop in the state before the pressure loss, to prevent the furnace door 3 from loosening and causing the quenching oil vapor to flow into the carburizing chamber, thereby avoiding affecting the product quality.

[0025] like Figure 2 As shown, a first one-way throttle valve 14a is provided between the first air outlet 12a and the inlet of the first pilot check valve 13a, and a second one-way throttle valve 14b is provided between the second air outlet 12b and the inlet of the second pilot check valve 13b. The first one-way throttle valve 14a and the second one-way throttle valve 14b respectively limit the maximum flow rate of the two-way flow of gas.

[0026] Because the conjugate protection device 1 controls the opening and closing of the furnace door 3, the first one-way throttle valve 14a and the second one-way throttle valve 14b can be used to control the speed of movement of the furnace door 3 to avoid excessive collision that damages parts and generates noise.

[0027] like Figure 1 and Figure 2 As shown, the rodless chamber outlet of the cylinder 11 is provided with a first manual exhaust device 15 a , and the rod chamber outlet of the cylinder 11 is provided with a second manual exhaust device 15 b .

[0028] When a problem occurs with the conjugate protection device 1 and the furnace door 3 is already controllable, the cylinder 11 can be manually vented so that the conjugate protection device 1 can be completely removed for maintenance.

[0029] like Figure 2 As shown, a fixing seat 16 is provided on the outer wall of the cylinder 11 , and the four-position five-way reversing valve 12 is fixed on the fixing seat 16 .

[0030] In the assembled structure, the 4 / 5-way directional valve 12 is connected to various parts by numerous thin tubes. However, these thin tubes lack sufficient support strength and are prone to loosening under operational vibrations. Therefore, the 4 / 5-way directional valve 12 must be secured to the outer wall of the cylinder 11 via a fixing seat 16 to maintain the structural stability of the conjugate protection device 1.

[0031] The above descriptions are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A conjugate protection device for a furnace door drive cylinder, characterized in that: It includes a cylinder, a four-position five-way reversing valve, a first pilot check valve and a second pilot check valve. The four-position five-way reversing valve has a first air outlet and a second air outlet. The first air outlet is connected to the rodless chamber of the cylinder through the first pilot check valve, and the second air outlet is connected to the rod chamber of the cylinder through the second pilot check valve. The first air outlet is provided with a first branch connected to the pilot port of the second pilot check valve, and the second air outlet is provided with a second branch connected to the pilot port of the first pilot check valve. When the first air outlet loses pressure, the gas can only flow from the first air outlet to the rodless chamber in one direction. When the second air outlet loses pressure, the gas can only flow from the second air outlet to the rod chamber in one direction.

2. The conjugate protection device for the furnace door drive cylinder according to claim 1, characterized in that: A first one-way throttle valve is provided between the first air outlet and the inlet of the first pilot check valve, and a second one-way throttle valve is provided between the second air outlet and the inlet of the second pilot check valve. The first one-way throttle valve and the second one-way throttle valve respectively limit the maximum flow rate of the two-way flow of gas.

3. The conjugate protection device for the furnace door drive cylinder according to claim 1, characterized in that: The rodless cavity outlet of the cylinder is provided with a first manual exhaust device, and the rod cavity outlet of the cylinder is provided with a second manual exhaust device.

4. The conjugate protection device for the furnace door drive cylinder according to claim 1, characterized in that: A fixing seat is provided on the outer wall of the cylinder, and the four-position five-way reversing valve is fixed on the fixing seat.

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