CN203259839U

CN203259839U - Differential pressure protection device for cryopump control box

Info

Publication number: CN203259839U
Application number: CN 201320302098
Authority: CN
Inventors: 王宏; 吴志东; 芮艳如
Original assignee: Tianjin General Facility Service Science & Technology Co Ltd
Current assignee: Tianjin General Facility Service Science & Technology Co Ltd
Priority date: 2013-05-29
Filing date: 2013-05-29
Publication date: 2013-10-30
Anticipated expiration: 2023-05-29

Abstract

The utility model discloses a differential pressure protection device for a cryopump control box, which can be arranged between a power supply and a PLC. The differential pressure protection device for the cryopump control box comprises an indicating lamp, an intermediate relay and a differential pressure switch. The differential pressure switch and a power end of the relay are serially connected with a system power supply. A normally-closed-set contact and a normally-open-set contact of the relay are both electrically connected with the system power supply. The normally-closed-set contact is grounded through the indicating lamp. The normally-open-set contact of the relay is electrically connected with the PLC. The differential pressure protection device has the beneficial effects that pressure values of an outlet and an inlet of a pump are detected with the differential pressure switch when the pump is in operation; when a differential pressure value is within a specified range, a normally open set of the relay is connected, and the PC is connected with the power supply to control a current cryopump, and thus a function of differential pressure protection is achieved; and with the differential pressure protection, the body of the cryopump is protected from cavitation, the flow, lift and efficiency are also protected, and chemical corrosion is prevented.

Description

The differential pressure security device of low temperature pump control box

Technical field

The utility model relates to a kind of tank car low temperature pump control box; The differential pressure security device that particularly relates to a kind of tank car low temperature pump control box.

Background technology

Tank car transportation development at home is increasingly general, and the control system of tank car mainly is by low temperature pump control box, as China Patent Publication No. be 201159844Y disclose a kind of low temperature pump control box include direct connection and drive the cryopump motor major loop, be provided with the main control loop of master controller, and link to each other with major loop, main control loop respectively, receive the signal of main control loop and control the second control loop of major loop, wherein, major loop is by ac power supply, and main control loop and the second control loop are by DC power supply.Above-mentioned patent has running current and shows that overheating protection is arranged, one jiao of startups of motor star, and phase sequence measuring ability, hours of operation show, 4 minutes nothings operate then the functions such as pump trip.Dwindled the motor control system volume, wiring is simple and clear, and all components and parts are all sealed, has effectively prevented from becoming flexible the protection of console panel casing waterproof splashproof, degree of protection IP65.Have this locality, operated from a distance, make operation easier, safer for the operator.And reduced the cost of equipment, and prolonged the serviceable life of equipment, saved electric power.But technique scheme lacks the safeguard procedures to cavitation.The harm that cavitation can produce, as, 1, produce noise and vibration; 2 make flow, lift, Efficiency Decreasing; 3, the water pump vane surface can be subject to impact and the erosion of cavitation; 4, the steam bubble condensation heat causes chemical corrosion.Can make the pump housing and whole control system bring harm.

Summary of the invention

Technical problem to be solved in the utility model is that a kind of differential pressure security device that can effectively prevent the low temperature pump control box of cavitation hazard is provided.

The technical scheme that the utility model adopts is: a kind of differential pressure security device of low temperature pump control box is provided with the differential pressure security device between power supply and PLC controller; Comprise pilot lamp, auxiliary reclay and pressure difference switch; The power end of described pressure difference switch and relay is connected in series on the system power supply, the normally closed winding point of relay, often open winding point and be electrically connected with system power supply respectively, normally closed winding point is by pilot lamp ground connection, and the winding point of often opening of relay is electrically connected with the PLC controller.

Described pressure difference switch is selected the FD16Q series of GEORGIN.

The beneficial effects of the utility model are; force value by pressure difference switch testing pump outlet and entrance when the pump operation; when pressure difference meets setting range; the winding of often opening that is relay is led to; power supply access PLC controller; by the PLC controller current cryopump is controlled, thereby realized the differential pressure security function.Differential pressure security makes the pump housing of cryopump play the protection of preventing cavitation, and to flow, lift and efficient have also played protective effect, have prevented chemical corrosion.

Description of drawings

Fig. 1 is the electrical schematic diagram of the differential pressure security device of the utility model low temperature pump control box;

Fig. 2 is the electrical schematic diagram of pressure difference switch.

Embodiment

Below in conjunction with the drawings and specific embodiments the utility model is described in further detail:

As depicted in figs. 1 and 2, the differential pressure security device of the utility model low temperature pump control box is provided with the differential pressure security device between power supply and PLC controller; The differential pressure security device comprises, pilot lamp H, auxiliary reclay KA and pressure difference switch; Described pressure difference switch is selected the FD16Q series of GEORGIN, be characterized in and can move under low temperature environment, and sensitivity will exceed much than general pressure difference switch.The power end of described pressure difference switch and relay K A is connected in series on the system power supply, the normally closed winding point 22 of relay K A, often open winding point 14 and be electrically connected with system power supply respectively, the normally closed winding point 21 of relay K A is by pilot lamp H ground connection, and the winding point 11 of often opening of relay K A is electrically connected with the PLC controller.

The principle of work of the differential pressure security device of the utility model low temperature pump control box is: as the basis, increased relay and pressure difference switch with existing low temperature pump control box principle and wiring.Force value by pressure difference switch testing pump outlet and entrance when the pump operation; when pressure difference meets setting range, namely relay K A often to open winding logical, power supply access PLC controller; by the PLC controller current cryopump is controlled, thereby realized the differential pressure security function.

Force value by pressure difference switch testing pump outlet and entrance when the pump operation, when pressure difference meets setting range, pressure difference switch is connected, relay K A gets electric adhesive, the winding of often opening of relay K A is led to, power positive end is often opened group by relay K A's, gives signal of PLC controller, makes pump keep running; Otherwise; then relay K A can not adhesive; the PLC controller can not get electric; and power supply passes through the normally closed group of contact of relay K A to pilot lamp H plugged, and the pressure difference of pilot lamp H alarm indication pump discharge and entrance does not meet setting range; when the time that reaches PLC controller inner setting, (25s) do not detect the pressure difference signal yet; the PLC controller stops output, and namely pump is out of service, plays the effect of protection system.

The utility model is by the force value of pressure difference switch testing pump outlet and entrance when the pump operation; when pressure difference meets setting range, namely relay K A often to open winding logical, power supply access PLC controller; by the PLC controller current cryopump is controlled, thereby realized the differential pressure security function.

Claims

1. the differential pressure security device of a low temperature pump control box is characterized in that, is provided with the differential pressure security device between power supply and PLC controller; Comprise pilot lamp (H), auxiliary reclay (KA) and pressure difference switch; The power end of described pressure difference switch and relay (KA) is connected in series on the system power supply, the normally closed winding point (22) of relay (KA), often open winding point (14) and be electrically connected with system power supply respectively, normally closed winding point (21) is by pilot lamp (H) ground connection, and the winding point (11) of often opening of relay (KA) is electrically connected with the PLC controller.

2. the differential pressure security device of low temperature pump control box according to claim 1 is characterized in that, described pressure difference switch is selected the FD16Q series of GEORGIN.