JP2007278575A - Drain collecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drain collecting device capable of reducing generation of flash steam and efficiently collecting drain, with respect to the drain collecting device circulating the drain discharged from a steam usage appliance applying steam as a heat source, to a boiler. <P>SOLUTION: In a steam circulating system for circulating the drain stored in a drain tank to the boiler, a pair of drain outflow pipes 7a, 7b are disposed at a lower part from a bottom portion of the drain tank, check valves 8a, 8b are disposed on the way of each of drain outflow pipes, a pair of cylinders 9a, 9b and right and left reciprocating pistons 11a, 11b are disposed at a part lower than the drain tank, both cylinders are provided with drain collecting pipes 15a, 15b extending downward, the drain collecting pipes are connected with both end portions of a three-way switch valve 12 moving right and left by water pressure, and the drain is alternately pressure fed from both drain outflow pipes to the drain collecting pipe by operating the pistons. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drain recovery device that circulates drain discharged from steam-utilizing equipment to a boiler in a clothing cleaning factory, a textile factory, a paper mill, or the like that uses steam as a heat source.

  For example, clothing cleaning factories are equipped with steam-using equipment such as continuous washing machines called batch washers, batch-type washing machines, or clothes dryers, and supply steam generated by boilers to these steam-using equipment. The steam is used as a heat source. A sealed drain tank is connected to the steam discharge pipe of the steam-utilizing device via a steam trap, and the drain stored in the drain tank is recirculated to the boiler by a pump. In addition, the flash vapor generated by re-evaporating a part of the drain in the drain tank is reused for other steam utilization devices.

The steam utilization apparatus of the cleaning factory shown in the following Patent Document 1 intends to recover heat by supplying flash steam generated from the drain to steam utilization equipment such as a water heater.
JP 2004-81718 A

  By the way, as described above, the steam generated in the boiler is supplied to the steam utilization equipment, and a sealed drain tank is connected to the steam discharge pipe of the steam utilization equipment via the steam trap, and stored in the drain tank. In a steam circulation system in which the drained water is recirculated to the boiler by a pump and a part of the drain is re-evaporated in the drain tank and the generated steam is reused. However, there is a problem that the efficiency of recovering the drain in the drain tank to the boiler is remarkably deteriorated because the inside of the cylinder becomes negative pressure and the flash vapor is generated and the volume increases when the drain is sucked. there were.

  The present invention provides a drain recovery device that can solve the above-described problems, and supplies steam generated in a boiler to steam utilization equipment, and a sealed drain through a steam trap to a steam discharge pipe of the steam utilization equipment. In a steam circulation system for connecting a tank and circulating the drain stored in the drain tank to the boiler, a pair of large-diameter drain outlet pipes are connected to the drain tank so that the drain in the drain tank can flow out by its own weight. A check valve is provided below the bottom, and is opened in the middle of each drain outflow pipe by its own weight. A pair of cylinders are provided substantially horizontally below the drain tank. Pistons that reciprocate to the left and right are provided, the lower ends of the drain outlet pipes are connected to the cylinders, and the drains of the drain outlet pipes are connected to the lower ends. The recovery pipe is extended downward, and the lower ends of both drain recovery pipes are connected to both ends of the three-way switching valve. A valve body is provided to close the drain recovery pipe on the side and connect the drain recovery pipe on the high pressure side to the drain recovery port of the boiler. When the piston operates, the drains of both drain outlet pipes are alternately sucked into both cylinders. It is characterized by being alternately pumped to the recovery pipe.

  This is a drain recovery device that recirculates drain discharged from steam-utilizing equipment using steam as a heat source to the boiler, so that generation of flash steam is suppressed and drain is recovered efficiently.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a piping diagram of a steam circulation system according to the present invention. In the figure, 1 is a boiler that generates saturated steam at a pressure of 0.9 MPa and a temperature of about 180 ° C., 2 is steam used in a clothes dryer or the like in which steam generated in the boiler is supplied through a pipe 3 and used as a heat source. Equipment. Reference numeral 4 denotes a sealed drain tank connected to the steam discharge pipe of the steam-using device via a steam trap 5, and the saturated temperature drain that has lost its latent heat by passing through the steam-using device is the steam trap. 5 is stored in the drain tank 4. In the drain tank 4, a part of the stored drain is re-evaporated to generate flash steam at a pressure of about 0.2 MPa. Therefore, the flash steam passes through the pressure regulating valve 6 and is used in a washing machine or the like. It is sent to other steam utilization equipment (not shown) and reused. The drain tank 4 is provided with a liquid level control device 4a that detects the drain liquid level in the drain tank 4 and operates an actuator 10 described later for drain discharge.

  7a and 7b are a pair of large-diameter drain outlet pipes disposed downward from the bottom of the drain tank so that the drain in the drain tank 4 can flow out by its own weight, and 8a and 8b are provided in the middle of the drain outlet pipes. It is a check valve provided to be opened by the dead weight of the drain. Further, 9a and 9b are a pair of cylinders provided substantially horizontally at a lower position than the drain tank, and 10 is an actuator such as an air cylinder provided between the cylinders, which protrudes from both ends of the actuator. The rods 10a and 10b are provided with pistons 11a and 11b. The pistons 11a and 11b are configured to reciprocate left and right within the cylinders 9a and 9b when the actuator 10 is operated. The lower ends of the drain outlet pipes 7a and 7b are connected to the cylinders 9a and 9b, respectively.

  Reference numeral 12 denotes a three-way switching valve provided to communicate with the drain recovery port 13 of the boiler 1, and reference numeral 14 denotes a plate-like valve body provided in the three-way switching valve 12. Drain recovery pipes 15 a and 15 b extend downward from the lower parts of the drain outflow pipes 7 a and 7 b, respectively, and the lower ends of the drain recovery pipes are connected to both ends of the three-way switching valve 12. For this reason, the valve body 14 moves to the left and right by the water pressure of both drain recovery pipes 15a and 15b, closes the low-pressure side drain recovery pipe and allows the high-pressure side drain recovery pipe to communicate with the drain recovery port 13 of the boiler 1.

  In the drain recovery apparatus configured as described above, the drain stored in the drain tank 4 flows out into the drain outflow pipes 7a and 7b by its own weight, and flows into the cylinders 9a and 9b through the check valves 8a and 8b. When drain is accumulated in the drain tank 4 beyond a certain level, the actuator 10 moves the pistons 11a and 11b to the right in the cylinders 9a and 9b as shown in FIG. For this reason, the pressure in the cylinder 9a rises, the drain accumulated in one drain outflow pipe 7a is pushed out to the drain collection pipe 15a, and the water pressure in the drain collection pipe 15a also rises. The drain collecting pipe 7 a is moved to communicate with the drain collecting port 13, and the drain is pushed to the boiler 1. At this time, the check valve 8a is closed to prevent the backflow of the drain in the drain recovery pipe 15a. At that time, the drain stored in the drain tank 4 further flows into the cylinder 9b through the drain outflow pipe 7b by its own weight, and the valve body 14 moves to the left so that the valve body 14 Since the drain on the left side is pushed back to the drain recovery pipe 15b, there is almost no possibility of negative pressure in the cylinder 9b.

  Next, when the piston 11b is moved as shown in FIG. 1 by the actuator 10, the pressure in the cylinder 9b rises, and the drain accumulated in the drain outflow pipe 7b is pushed out to the drain recovery pipe 15b and the water pressure in the drain recovery pipe is increased. Therefore, the valve body 14 is moved to the right, the drain collection pipe 7b is communicated with the drain collection port 13, and the drain is pushed to the boiler 1. At this time, the check valve 8b is closed to prevent the backflow of the drain in the drain recovery pipe 15b. At this time, there is almost no possibility that the inside of the cylinder 9a becomes a negative pressure, and the drain can flow out from the drain tank 4 to the drain outflow pipe 7a by its own weight.

  As described above, in the present invention, the drain that flows out of the drain tank 4 by its own weight and accumulates in the drain outlet pipes 7a and 7b is recovered in the boiler 1 by reciprocating the pistons 11a and 11b alternately by the actuator 10. Therefore, drain recovery can be performed efficiently without generating flash steam in the cylinders 9a and 9b and the drain outlet pipes 7a and 7b.

  In this embodiment, an air cylinder is used as the actuator 10, but another prime mover such as a hydraulic cylinder or an electric motor may be used. Moreover, you may use the actuator comprised so that the piston rod which connects an air cylinder and a piston might be abbreviate | omitted by making piston 11a, 11b guide | induced with a strong permanent magnet. The drain outflow pipes 7a and 7b are preferably those having a large diameter of 50 mm or more in order to reduce the flow rate of the drain in order to reduce the generation of flash vapor from the drain as much as possible.

It is a piping diagram of the drain collection device concerning the present invention. It is an operation state figure of the drain recovery device of Drawing 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Boiler 2 Steam | steam utilization equipment 4 Drain tank 5 Steam trap 6 Pressure control valve 7a, 7b Drain outflow pipe 8a, 8b Check valve 9a, 9b Cylinder 10 Actuator 11a, 11b Piston 12 Three-way switching valve 13 Drain collection port 14 Valve body 15a 15b Drain recovery pipe

Claims (1)

  The steam generated in the boiler is supplied to the steam utilization equipment, and a sealed drain tank is connected to the steam discharge pipe of the steam utilization equipment via a steam trap, and the drain stored in the drain tank is circulated to the boiler. In the steam circulation system to be drained, a pair of large diameter drain outlet pipes are arranged downward from the bottom of the drain tank so that drain in the drain tank can flow out by its own weight. A check valve that opens due to its own weight is provided, a pair of cylinders are provided substantially horizontally below the drain tank, a piston that reciprocates left and right by an actuator is provided in the cylinder, and the drain outflow pipes are provided in both cylinders. The lower ends are connected to each other, and the drain recovery pipes are extended downward from the lower parts of both drain outflow pipes. The lower ends of the drain recovery pipes are switched in three directions. The three-way switching valve is connected to the drain recovery pipe of the boiler by closing the low-pressure side drain recovery pipe and moving the high-pressure side drain recovery pipe to the left and right by the water pressure of both drain recovery pipes. A drain recovery apparatus characterized in that a body is provided, and drains of both drain outflow pipes are alternately sucked into both cylinders and alternately pumped into both drain recovery pipes by operating the piston.

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