CN204717346U

CN204717346U - A kind of Marine vacuum powder isolation LNG basin fluid level control device

Info

Publication number: CN204717346U
Application number: CN201520370520.1U
Authority: CN
Inventors: 杨鹏; 毛海涛; 戢升东
Original assignee: JIANGXI OXYGEN PLANT CO Ltd
Current assignee: JIANGXI OXYGEN PLANT CO Ltd
Priority date: 2015-06-02
Filing date: 2015-06-02
Publication date: 2015-10-21
Anticipated expiration: 2025-06-02

Abstract

A kind of Marine vacuum powder isolation LNG basin fluid level control device, comprise inner container, shell, inner container and shell one end are provided with temperature measuring equipment, described temperature measuring equipment comprises temperature measuring head, temperature transmitter, metal bellows, temperature measuring equipment exports connection control device, described inner container geometric volume 85% position is provided with the first temperature measuring equipment, inner container geometric volume 20% position is provided with the second temperature measuring equipment, inner container geometric volume 90% position is provided with monitoring pipe, and described monitoring pipe exports and connects pneumatic valve, concentrated exhaust stack and the 3rd temperature measuring equipment by the road.Solving the inaccurate problem with there is potential safety hazard of landing stage LNG vacuum-powders insulation basin level gauging, having and measuring feature accurate, easy to use, and less on the impact of container.

Description

A kind of Marine vacuum powder isolation LNG basin fluid level control device

Technical field

The utility model relates to a kind of Marine vacuum powder isolation LNG basin fluid level control device.

Background technique

As everyone knows, the density of LNG can the notable change along with the change of its temperature, therefore landing stage LNG vacuum-powders insulation refrigerated storage tank all requires that its specified filling rate is less than 0.9, with after avoiding filling because density reduces, volumetric expansion and occur that inner container gas-phase space is the situation of zero at short notice, once there is this situation, due to the incompressibility of liquid, fluid density in inner container slightly reduces and its pressure will be caused sharply to raise, this will bring very large hidden danger to the safe operation of landing stage LNG vacuum-powders insulation refrigerated storage tank, therefore in all landing stage LNG vacuum-powders insulation refrigerated storage tanks, all must there is parts---the liquid-level switch that very important, its effect is: when filling liquid level and reach 85% alarm of inner container geometric volume, when liquid level reaches 90% of inner container geometric volume, will automatically cut off liquid entering hole valve, 20% alarm that liquid level reaches inner container geometric volume is worked as when unloading liquid.

Now nearly all landing stage LNG vacuum-powders insulation refrigerated storage tank, be all employing two we be referred to as the level meter of differential manometer and monitoring pipe to realize liquid-level switch, the liquid-level switch of this form mainly contain following shortcoming:

(1) measure inaccurate, differential pressure type level gauge utilizes the pressure difference of upper and lower two liquid levels of liquid to measure liquid level, and therefore its measuring accuracy and fluid density are inversely proportional to, due to its natural gas liquid and temperature different, density has very large difference, and integrating its error rate will be greater than 10%.

Adopt monitoring pipe measure because of to detect by an unaided eye from monitoring pipe outflow be steam or liquid, therefore just the natural gas steam in inner container or liquid must be released, although level gauging is more accurate, but due to release natural gas steam or liquid be inflammable and low temperature, do very large potential safety hazard like this.

Model utility content

Its object of the utility model is just to provide a kind of Marine vacuum powder isolation LNG basin fluid level control device, solve the inaccurate problem with there is potential safety hazard of landing stage LNG vacuum-powders insulation basin level gauging, have and measure feature accurate, easy to use, and less on the impact of container.

Realize above-mentioned purpose and the technological scheme taked, comprise inner container, shell, inner container and shell one end are provided with temperature measuring equipment, described temperature measuring equipment comprises temperature measuring head, temperature transmitter, metal bellows, temperature measuring equipment exports connection control device, described inner container geometric volume 85% position is provided with the first temperature measuring equipment, inner container geometric volume 20% position is provided with the second temperature measuring equipment, inner container geometric volume 90% position is provided with monitoring pipe, and described monitoring pipe exports and connects pneumatic valve, concentrated exhaust stack and the 3rd temperature measuring equipment by the road.

beneficial effect

Compared with prior art the utility model has the following advantages.

(1) it is comparatively accurate to measure, and the temperature transmitter used now is all adopt platinum resistor temperature measuring element, and precision can reach 0.1 grade, and in inner container, the temperature difference of LNG steam and liquid is comparatively large, is easy to flutter and grasps temperature jump point, thus realize liquid-level switch more exactly;

(2) less to the intensity effect of inner container, due to the unique texture of vacuum-powders insulation, some level gaugings liquid-level switch more accurately, such as Fork LIquid Level Switch all must adopt the mode of Flange joint to be connected with inner container and shell, like this one is produce a very large impact the intensity of inner container, moreover Flange joint is as produced micro-leakage, also can affect the degree of vacuum of interlayer.

Accompanying drawing explanation

Below in conjunction with accompanying drawing, the utility model is described in further detail.

Fig. 1 is this apparatus structure schematic diagram.

Embodiment

This device comprises inner container 1, shell 2, inner container 1 and shell 2 one end are provided with temperature measuring equipment, described temperature measuring equipment comprises temperature measuring head, temperature transmitter, metal bellows, temperature measuring equipment exports connection control device, as shown in Figure 1, described inner container 1 geometric volume 85% position is provided with the first temperature measuring equipment 4, inner container geometric volume 20% position is provided with the second temperature measuring equipment 8, inner container geometric volume 90% position is provided with monitoring pipe 3, and described monitoring pipe 3 exports and connects pneumatic valve 5, concentrated exhaust stack 6 and the 3rd temperature measuring equipment 7 by the road.

A temperature measuring equipment is at least provided with between described first temperature measuring equipment 4 and the 4th temperature measuring equipment 8.

Embodiment

This device utilizes the temperature measuring equipment on inner container and pipeline to be used as liquid-level switch, temperature measuring equipment is made up of three parts, temperature measuring head, temperature transmitter, metal bellows respectively, wherein temperature measuring head is made up of S30408 III material, be welded to connect with inner container, temperature transmitter adopts platinum resistor temperature measuring mode, and precision can reach 0.1 grade, and mounting or dismounting are convenient.

A kind of multicomponent mixture based on LNG, the change of its temperature and component can cause the change of density, stratification can be there is because of density variation in the LNG of different densities when storing, layering can cause LNG to roll to a certain extent, can with the sharp increase of liquid surface relative evaporation during rolling, and show that the play of basin internal pressure rises and the increasing considerably of steam flow, as there is this situation, quite dangerous concerning the operation of LNG vacuum-powders insulation basin, there is rolling for avoiding LNG first just to measure its temperature, a point for measuring temperature is established every being no more than 2 meters according to the liquid level degree of depth, as shown in Figure 1, when refrigerated storage tank fills, due to heat radiation and some other reason, in inner container, LNG steam and fluid temperature have larger difference, experimentally detect its difference at about 10 DEG C, that is time as started, some point for measuring temperature contacts is steam, but along with rising temperature when point for measuring temperature contact is liquid of liquid level can produce a sudden change, position due to point for measuring temperature is fixing, so just can realize liquid-level switch by the mode of thermometric.

Working principle

(1) as shown in Figure 1, start to fill LNG, now in the LNG steam of the first temperature measuring equipment 4, second temperature measuring equipment 8 all more than liquid level;

(2) along with the rising of liquid level, liquid level is successively more than the second temperature measuring equipment 8, first temperature measuring equipment 4, when liquid level is more than the first temperature measuring equipment 4(geometric volume 85% position) time, temperature jump triggers temperature measuring equipment and produces electrical signal, control gear opens monitoring pipe pneumatic valve 5 according to electrical signal, carries out 85% liquid level warning simultaneously:

(3), when liquid level continues to rise, liquid flows out through monitoring pipe 3, pneumatic valve 5, concentrated exhaust stack 6, now the 3rd temperature measuring equipment 7 contact liq, and temperature jump triggers temperature measuring equipment and produces electrical signal, and control gear cuts out according to electrical signal and fills mouth, and topping up stops.

This cover liquid-level switch also has low liquid level warning function, along with the liquid in the LNG vacuum insulation basin of landing stage is constantly used, liquid level declines gradually, when liquid level is lower than the second temperature measuring equipment 8(geometric volume 20% position) time, temperature will be undergone mutation, 20% low liquid level warning.

Claims

1. a Marine vacuum powder isolation LNG basin fluid level control device, comprise inner container (1), shell (2), inner container (1) and shell (2) one end are provided with temperature measuring equipment, described temperature measuring equipment comprises temperature measuring head, temperature transmitter, metal bellows, temperature measuring equipment exports connection control device, it is characterized in that, described inner container (1) geometric volume 85% position is provided with the first temperature measuring equipment (4), inner container geometric volume 20% position is provided with the second temperature measuring equipment (8), inner container geometric volume 90% position is provided with monitoring pipe (3), described monitoring pipe (3) exports and connects pneumatic valve (5) by the road, concentrate exhaust stack (6) and the 3rd temperature measuring equipment (7).

2. a kind of Marine vacuum powder isolation LNG basin fluid level control device according to claim 1, is characterized in that, be at least provided with a temperature measuring equipment between described first temperature measuring equipment (4) and the 4th temperature measuring equipment (8).