JPS6053244B2 - Condensate recovery pump device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a condensate recovery pump device used for recovering condensate generated in a steam system to a condensate usage system such as a boiler or other low pressure steam system.

Conventionally, this type of condensate recovery pump device is often used by being directly connected to a location where condensate is generated in a steam system.

However, when the condensate recovery pump device is directly connected to the condensate generation point in the steam system, the pressure required for the condensate discharged from the condensate generation point to flow to the suction side of the condensate recovery pump device A gradient was required, and it was difficult to create this pressure gradient, making it impossible to smoothly collect condensate. Furthermore, a steam trap or fixed orifice is often installed at the condensate generation point, and if the suction side of the condensate recovery pump device is directly connected to the condensate generation point, a steam trap or fixed orifice is installed at the condensate generation point. The pressure on the outlet side of the valve increases, making it impossible to maintain the differential pressure between the inlet and outlet sides required for operation, resulting in unstable operation or malfunction. Also,
The amount of condensate generated within the steam system varies depending on the operating status of the steam system, and the problem is that the recovery capacity of the condensate recovery pump device exceeds the amount of condensate generated, causing steam to be sucked into the device and hindering the recovery action. It was hot too. In view of the above circumstances, the present invention creates a pressure gradient from the condensate generation point in the steam system to the suction side of the condensate recovery pump device, and enables variable condensate recovery depending on the amount of condensate generation. It is an object of the present invention to provide a condensate recovery pump device that can smoothly recover condensate and can secure the differential pressure between the inlet and outlet sides necessary for operating a steam trap and a fixed orifice.

That is, the present invention provides an electric pump, a cooling water injection passage for injecting cooling water into the suction port side of the electric pump, a valve disposed in the cooling water injection passage, and a pressure sensor for detecting the pressure on the suction port side of the electric pump. a detection means, a means for operating a valve disposed in the cooling water injection passage based on a signal from the pressure detection means, a liquid amount detection means for detecting the amount of condensed water on the suction port side of the electric pump, and a liquid amount detection means on the discharge port side of the electric pump. The above objective is achieved by a condensate recovery pump device comprising a valve arranged on the discharge port side of the electric pump and a means for operating the valve arranged on the discharge port side of the electric pump in response to a signal from the liquid amount detection means. In this case, electric pumps include centrifugal pumps such as centrifugal pumps that can pump high-temperature liquids and are relatively efficient, and cooling water injection to create the supercooled state necessary for pump operation with a small required forced water head. A cascade pump, etc. that can reduce the amount of water is suitable.

Low-temperature water such as boiler feed water is used as the cooling water injected into the suction port side of the electric pump.

Further, the cooling water injection passage may be provided with a regular injection passage that constantly injects the necessary minimum amount of cooling water in order to create the minimum supercooled state necessary for operation of the electric pump. This regular injection passage allows cooling water to flow without passing through the valve. It is formed by providing a bypass passage for the valve to pass through or a normally open hole in the valve itself. Furthermore, when using a bypass passage, the amount of cooling water passing through can be changed by making it possible to insert orifice plates of different diameters, or installing a separate throttle valve.
For example, the range of application of the device can be expanded. The valves placed in the cooling water injection passage and the valves placed on the suction port side of the electric pump use flow rate control valves that change the opening degree according to signals from the following operating means, and have particularly high sensitivity and accuracy. An electric type using a stepping motor is suitable because it is relatively compact. The pressure detection means detects whether a pressure gradient has been created on the suction port side of the electric pump, and the number of detections is changed as appropriate depending on the state of the steam system.

For example, if the pressure in the steam system is stable, the presence or absence of a pressure gradient can be determined by detecting only the pressure at one point on the suction side of the electric pump; if the pressure in the steam system is unstable, the This is because it is necessary to detect the pressure and the pressure at two points on the suction port side of the electric pump in order to determine the presence or absence of a pressure gradient. The means for operating the valve disposed in the cooling water injection passage with a signal from the pressure detection means, and the means for operating the valve disposed on the discharge port side of the electric pump using a signal l from the liquid amount detection means, are microcontrollers made of LSI. A computer is used.

As the liquid level detection means, one that measures the flow rate of condensate flowing through the suction port side of the electric pump, or one that combines a condensate reservoir and a liquid level detection means that detects the liquid level in the condensate reservoir is used. The above-mentioned flow rate measuring device can be easily attached to the suction port side of an electric pump and can accurately measure the amount of condensate, and is also a combination of a condensate reservoir and a liquid level detection means for detecting the liquid level in the condensate reservoir. In this case, the action of the condensate reservoir can prevent steam, etc. from being sucked into the electric pump, and the device can be operated safely.

Next, an embodiment of the present invention shown in the drawings will be described.

In FIG. 1, 1 indicates an electric pump driven by an electric motor. Reference numeral 2 indicates a suction port side passage communicating with the suction port 3 of the electric pump 1, and this passage 2 guides condensate from the condensate generation location 4 to the suction port 3 side of the electric pump 1.

Reference numerals 5 and 6 indicate pressure detection means disposed on the inlet and outlet sides of the condensate generation location 4, which electrically detect the pressure and send electrical signals to the operating means described below.

A broken line 7 indicates a signal transmission line. Reference numeral 8 indicates a cooling water injection passage communicating with the suction port side passage 2, through which cooling water is injected into the suction port 3 side of the electric pump 1.

In this case, the cooling water is pressurized to a higher pressure than the pressure on the suction port 3 side. Reference numeral 9 designates a valve disposed in the cooling water injection passage 8, whose opening degree is changed in response to a signal from the operating means described below to adjust the amount of cooling water injected.

Reference numeral 10 denotes a bypass passage through which the cooling water always passes without passing through the valve 9, and a throttle valve 11 is disposed in this passage 10.

This throttle valve 11 is adjusted to an opening degree that allows the minimum amount of cooling water to pass through to create a supercooled state necessary for operation of the electric pump 1. Reference numeral 12 indicates an operating means, which processes the signals from the pressure detection means 5 and 6, calculates the differential pressure between the inlet side and the outlet side of the condensate generation point 4, and sets this differential pressure to a predetermined value (at the condensate generation point). A signal is sent to the valve 9 to change the opening degree by comparing the values (values set to create the pressure gradient necessary for the operation of steam-using devices, steam traps, fixed orifices, etc.).

For example, if the differential pressure is smaller than a predetermined value, a signal is sent to the valve 9 to increase the opening degree, and if the differential pressure is larger than the predetermined value, a signal is sent to the valve 9 to decrease the opening degree. In this way, cooling water is injected into the suction port side passage 2 to cool the condensate, and the pressure difference between the saturation pressure corresponding to the temperature of this condensate and the subsequent condensate is applied to the suction port 3 side of the electric pump 1. A supercooled state is created which acts as an indentation pressure, and the electric pump 1 can pressurize high-temperature condensate without internally reevaporating it.

At the same time, by injecting the cooling water, a pressure gradient is created in the suction side passage 2 from the outlet side of the condensate generation point 4 to the suction port 3 of the electric pump 1, and this pressure gradient is caused by the opening of the valve 9. It is adjusted and maintained at a predetermined state by changing the amount of cooling water injected as the temperature changes, so the steam using equipment, steam trap, fixed orifice, etc. at the condensate generation location 4 maintains a constant pressure gradient.
In other words, it can operate while the differential pressure between the inlet and outlet sides is maintained at a predetermined value, it can operate stably without becoming unstable or malfunctioning, and the condensate can be transferred to the suction port 3 of the electric pump 1. It can flow smoothly to the side. 13 is the suction port side passage 2
This condensate reservoir 13 is equipped with a liquid level detection means 14 that electrically detects the liquid level and sends an electrical signal to the operating means 12.

Reference numeral 15 indicates a blow passage that blows out condensate when the inside of the condensate reservoir 13 becomes full of water, and reference numeral 16 indicates a valve that opens and closes the blow passage 15.

Reference numeral 17 indicates a discharge port side passage communicating with the discharge port 18 of the electric pump 1, and guides the condensate pressurized within the electric pump 1 to a condensate use system (not shown).

Reference numeral 19 indicates a valve arranged in the discharge port side passage 17, and its opening degree is changed by a signal from the operating means 12.

The operating means 12 processes signals from the liquid level detecting means 14 as well as the signals from the pressure detecting means 5 and 6 as described above. For example, if the liquid level in the condensate reservoir 13 is high, a signal is sent to the valve 19 to increase the opening degree, and conversely, if the liquid level in the condensate reservoir 13 is low, a signal is sent to the valve 19 to decrease the opening degree. In this way, the valve 19 is operated according to the amount of condensate on the suction port 3 side of the electric pump 1, and the amount of condensate flowing through the discharge port side passage 17 is adjusted, so that the recovery of this condensate recovery pump device is determined based on the amount of condensate generated. The capacity is exceeded, and there is no need to worry about gas such as steam being sucked into the electric pump 1.

In addition, the condensate reservoir 13 separates the condensate from gases such as steam and allows only the condensate to flow toward the suction port 3 of the electric pump 1, so that gases such as steam are sucked into the electric pump 1. The chances are smaller. FIG. 2 shows a condensate recovery pump device according to another embodiment.

In the drawings, the same reference numerals are given to corresponding parts that are common to the embodiment shown in FIG. 1, and the explanation thereof will be omitted. 21 is the suction port side passage 2
A flow rate measuring means arranged at is shown, which measures the flow rate of condensate flowing toward the suction port 3 side of the electric pump 1 and sends an electrical signal to the operating means 22.

The operating means 22 processes the signal from the flow rate measuring means 21 together with the signals from the pressure detecting means 5 and 6, and sends a signal to change the opening degree of the valve 19 in proportion to the detected flow rate. In this way, the amount of condensate is measured and the discharge port side passage 17 is adjusted according to this amount.
The amount of condensate flowing through can be adjusted, the recovery capacity of the condensate recovery pump device exceeds the amount of condensate generated, and there is no fear that gas such as steam will be sucked into the electric pump 1.

Moreover, as in the embodiment shown in FIG.
Compared to a configuration that uses a condensate reservoir 13 and a liquid level detection means 14 for detecting the amount of condensate on the side, the configuration is simpler and is effective in making the device more compact.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a condensate recovery pump device according to one embodiment of the present invention, and FIG. 2 is a schematic diagram of a condensate recovery pump device according to another embodiment. 1 is an electric pump, 2 is a suction port side passage, 3 is a suction port, 4 is a condensate generation point, 5 and 6 are pressure detection means, 8 is a cooling water injection passage, 9 and 19 are valves, 10 is a bypass passage, 11 is a throttle valve, 12 and 22 are operating means, 13 is a condensate reservoir, 14 is a liquid level detecting means, 17 is a discharge port side passage, 18 is a discharge port, and 21 is a flow rate measuring means.

Claims (1)

[Claims] 1. An electric pump, a cooling water injection passage for injecting cooling water into the suction port side of the electric pump, a valve disposed in the cooling water injection passage, and detecting pressure on the suction port side of the electric pump. A pressure detection means, a means for operating a valve disposed in the cooling water injection passage based on a signal from the pressure detection means, a liquid amount detection means for detecting the amount of condensed water on the suction port side of the electric pump, and a discharge port side of the electric pump. and a means for operating the valve disposed on the discharge port side of the electric pump in response to a signal from the liquid level detection means, and operating a valve disposed in the cooling water injection passage in response to a signal from the pressure detection means. The means adjusts the amount of cooling water injected so as to create a predetermined pressure gradient on the suction port side of the electric pump, and the means operates a valve disposed on the discharge port side of the electric pump using a signal from the liquid amount detection means. A condensate recovery pump device characterized in that the discharge amount is adjusted according to the amount of condensate on the suction port side of an electric pump. 2 In the condensate recovery pump device according to claim 1, the cooling water injection passage is a regular injection passage through which the minimum amount of cooling water that creates a supercooled state necessary for operation of the electric pump is constantly passed through. A condensate recovery pump device comprising: 3. The condensate recovery pump device according to claim 2, wherein the normal injection passage is a bypass passage through which the cooling water passes without passing through the valve section. 4. In the condensate recovery pump device according to claim 1, the liquid amount detection means includes a condensate reservoir for storing condensate on the suction port side of the electric pump, and a liquid level in the condensate reservoir. A condensate recovery pump device characterized in that the condensate amount is detected by detecting the liquid level in the condensate reservoir using a liquid level detecting means. 5. The condensate recovery pump device according to claim 1, characterized in that the liquid amount detection means includes means for measuring the flow rate of condensate flowing toward the suction port side of the electric pump. Condensate recovery pump equipment.