CN109444022B - Filter oil-water separation efficiency test system - Google Patents

Filter oil-water separation efficiency test system Download PDF

Info

Publication number
CN109444022B
CN109444022B CN201811578416.6A CN201811578416A CN109444022B CN 109444022 B CN109444022 B CN 109444022B CN 201811578416 A CN201811578416 A CN 201811578416A CN 109444022 B CN109444022 B CN 109444022B
Authority
CN
China
Prior art keywords
water
oil
test
tank
oil tank
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201811578416.6A
Other languages
Chinese (zh)
Other versions
CN109444022A (en
Inventor
杨杰
范亚军
郭世红
王可超
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xinxiang Tianyi Filtering Technology Detection Co ltd
Original Assignee
Xinxiang Tianyi Filtering Technology Detection Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xinxiang Tianyi Filtering Technology Detection Co ltd filed Critical Xinxiang Tianyi Filtering Technology Detection Co ltd
Priority to CN201811578416.6A priority Critical patent/CN109444022B/en
Publication of CN109444022A publication Critical patent/CN109444022A/en
Application granted granted Critical
Publication of CN109444022B publication Critical patent/CN109444022B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/08Investigating permeability, pore-volume, or surface area of porous materials
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/08Investigating permeability, pore-volume, or surface area of porous materials
    • G01N2015/084Testing filters

Landscapes

  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Sampling And Sample Adjustment (AREA)

Abstract

The invention discloses a filter oil-water separation efficiency testing system which comprises a test oil tank unit, a water tank unit, a testing unit and an auxiliary mailbox unit, wherein an oil outlet of a test oil tank in the test oil tank unit is sequentially connected with a test pump, a heat exchanger, an oil flow regulating valve, an oil flowmeter, an upstream water dispersing device, a tested filter, a downstream water dispersing device and a liquid inlet of an auxiliary oil tank in an auxiliary oil tank system through pipelines, and a liquid outlet of the auxiliary oil tank in the auxiliary oil tank system is sequentially connected with an auxiliary purifying and replenishing pump, a preposed water removing filter, a circulating replenishing switching valve, a postposed water removing filter and an oil inlet of the test oil tank through pipelines. The invention can effectively avoid the span range selection of the flowmeter, avoid the use of a smaller liquid flowmeter, ensure that the multi-sleeve pipeline system accords with the pipe diameter selection of the flowmeter, and only need to replace the test pipe section to accord with the tested filter pipeline.

Description

Filter oil-water separation efficiency test system
Technical Field
The invention belongs to the technical field of filter performance testing devices, and particularly relates to a filter oil-water separation efficiency testing system.
Background
For the production, use and scientific research units of filter materials and filter elements, the oil-water separation efficiency is an essential performance index of the water removal and filtration performance, and the knowledge of the water removal and filtration efficiency result is essential key data for design, research and development and application, so that the conventional oil-water separation efficiency testing device has the defects of complex equipment, high cost, large using amount of test media and the like, and therefore, the device is necessary to be further improved.
Disclosure of Invention
The invention solves the technical problem of providing the filter oil-water separation efficiency test system which has simple structure, reasonable design and stable test, and the test system can effectively improve the test efficiency, improve the test accuracy and facilitate the monitoring test.
The invention adopts the following technical scheme for solving the technical problems, the filter oil-water separation efficiency testing system is characterized by comprising a test oil tank unit, a water tank unit, a testing unit and an auxiliary oil tank unit, wherein an oil outlet of the test oil tank in the test oil tank unit is sequentially connected with a test pump, a heat exchanger, an oil flow regulating valve, an oil flowmeter, an upstream water dispersing device, a tested filter, a downstream water dispersing device and a liquid inlet of an auxiliary oil tank in an auxiliary oil tank system through pipelines, a pipeline between the heat exchanger and the oil flow regulating valve is connected with an oil inlet of the test oil tank through an oil return pipeline, the oil return pipeline is provided with a test system pressurized overflow valve, a thermometer is arranged on the pipeline between the oil flow regulating valve and the flowmeter, a background sampling valve is arranged on the pipeline between the oil flowmeter and the upstream water dispersing device, two ends of the tested filter and the downstream water dispersing device are respectively connected with pressure gauges through pipelines in parallel, two ends of the tested filter are sequentially connected with a return branch circuit through a tested pipeline, the pipeline between the upstream water dispersing device and the tested filter is provided with an upstream sampling valve and a system pressure gauge, a pipeline between the upstream water dispersing device and the system pressure gauge is connected with an auxiliary oil inlet of the test oil tank through a return pipeline, the return pipeline is provided with a bypass valve and the auxiliary oil tank, the water collecting tank is sequentially connected with the water collecting tank through a bypass valve and the auxiliary oil tank, the water collecting tank is sequentially connected with the water tank through the water collecting tank through the water inlet, the auxiliary tank and the water collecting device, the water tank through the water collecting tank and the auxiliary tank, the water tank and the water tank through the water collecting device and the water tank, the water tank and the water tank through the water tank and the water tank. The water outlet of the water tank in the water tank unit is sequentially connected with the water injection pump, the water flow regulating valve, the water flowmeter and the upstream water dispersion device through pipelines, the pipeline between the water injection pump and the water flow regulating valve is connected with the water inlet of the water tank through a water return pipeline, the pressurized overflow valve is arranged on the water return pipeline, and the liquid outlet of the auxiliary oil tank in the auxiliary oil tank system is sequentially connected with the auxiliary purifying and replenishing pump, the preposed water removing filter, the circulating replenishment switching valve, the postposed water removing filter and the oil inlet of the test oil tank through pipelines, and the circulating replenishment switching valve is connected with the liquid inlet of the auxiliary oil tank through a return branch.
Further preferably, the upper part of the test oil tank is provided with a liquid level controller and a breathing filter with a drying function.
Further preferably, the upper part of the water tank is provided with a liquid level controller and a breathing filter with a drying function.
Further preferably, the upper part of the auxiliary oil tank is provided with a liquid level controller and a breathing filter with a drying function.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention can effectively avoid the span range selection of the flowmeter, avoid the use of a smaller liquid flowmeter, ensure that a multi-sleeve pipeline system accords with the pipe diameter selection of the flowmeter, and only need to replace a test pipe section to accord with a tested filter pipeline;
2. according to the invention, the water dispersing device is arranged at the upstream and downstream of the tested filter, and the tested filter is passed through the water dispersing device again to disperse the test medium, so that the water is recovered to the state before entering the tested filter, and the accuracy of downstream sampling and the authenticity of the content of the tested water are ensured;
3. according to the invention, the liquid level controller and the breathing filter with the drying function are arranged at the upper parts of the test oil tank, the water tank and the auxiliary oil tank, when the liquid level is increased, air in the container is discharged through the breathing filter, volatile oil gas is left in the container, when the liquid level is reduced, air is supplemented into the container, the pressure balance of the container is ensured, and meanwhile, in order to ensure that moisture particle dust and the like in the air do not pollute the medium in the container, the outside air is subjected to particle filtration and drying.
Drawings
Fig. 1 is a schematic structural view of the present invention.
In the figure: 1-test tank, 2-test pump, 3-heat exchanger, 4-oil flow regulating valve, 5-oil flow meter, 6-upstream water dispersion device, 7-tested filter, 8-downstream water dispersion device, 9-auxiliary tank, 10-test system pressurized overflow valve, 11-thermometer, 12-background sampling valve, 13-tested tube switching valve, 14-upstream sampling valve, 15-system pressure gauge, 16-bypass pump, 17-bypass water removal filter, 18-bypass flow meter, 19-downstream sampling valve, 20-oil collection tank, 21-auxiliary tank pump, 22-oil collection tank purification filter, 23-oil collection tank water removal filter, 24-water tank, 25-water injection pump, 26-water flow regulating valve, 27-water flow meter, 28-pressurized overflow valve, 29-auxiliary purification make-up pump, 30-pre-water removal filter, 32-circulation make-up switching valve, 32-post water removal filter, 33-liquid level controller, 34-respiratory filter.
Detailed Description
The details of the present invention are described in detail with reference to the accompanying drawings. As shown in FIG. 1, a filter oil-water separation efficiency test system comprises a test oil tank unit, a water tank unit, a test unit and an auxiliary oil tank unit, wherein an oil outlet of the test oil tank 1 in the test oil tank unit is sequentially connected with a test pump 2, a heat exchanger 3, an oil flow regulating valve 4, an oil flowmeter 5, an upstream water dispersing device 6, a tested filter 7, a downstream water dispersing device 8 and a liquid inlet of an auxiliary oil tank 9 in the auxiliary oil tank system through pipelines, the pipelines between the heat exchanger 3 and the oil flow regulating valve 4 are sequentially connected with an oil inlet of the test oil tank 1 through an oil return pipeline, a thermometer 11 is arranged on the oil return pipeline, a background sampling valve 12 is arranged on the pipeline between the oil flow regulating valve 4 and the oil flowmeter 5, a pressure gauge is arranged on the pipeline between the oil flowmeter 5 and the upstream water dispersing device 6, two ends of the tested filter 7 are respectively connected with a pressure gauge through pipelines in parallel, two ends of the tested filter 7 are sequentially connected with a return pipeline switching valve 13, an upstream water collecting valve 14 and a bypass valve 14 are arranged on the pipeline between the upstream water dispersing device 6 and the tested filter 7, a bypass valve 14 is sequentially arranged on the pipeline between the upstream water dispersing device 6 and the tested filter 7 and the auxiliary oil tank 1 is connected with an oil inlet of the test oil tank 1, a bypass valve 20 is arranged on the auxiliary oil tank 1, a bypass valve 19 is connected with a bypass valve 19, a bypass valve is arranged on the water tank 20 is connected with the water tank through a bypass valve 19, a bypass valve 20, a bypass valve is arranged on the bypass valve 20, a bypass valve 20 is connected between the water tank and a bypass valve 20, the auxiliary valve 20 is connected with the auxiliary oil tank through the pipeline, the auxiliary oil tank through a bypass valve 20, the auxiliary oil tank is connected with the auxiliary oil tank through a bypass valve 20, the auxiliary tank through a bypass valve, the auxiliary tank valve, the auxiliary tank valve and the auxiliary tank, the oil collecting tank purifying filter 22 and the oil collecting tank dewatering filter 23, the water outlet of the water tank 24 in the water tank unit is connected with the water injection pump 25, the water flow regulating valve 26, the water flow meter 27 and the upstream water dispersing device 6 in sequence through pipelines, the pipeline between the water injection pump 25 and the water flow regulating valve 26 is connected with the water inlet of the water tank 24 through a water return pipeline, the water return pipeline is provided with a pressurized overflow valve 28, the liquid outlet of the auxiliary oil tank 9 in the auxiliary oil tank system is connected with the auxiliary purifying replenishing pump 29, the front dewatering filter 30, the circulating replenishing switching valve 31, the rear dewatering filter 32 and the oil inlet of the test oil tank 1 in sequence through pipelines, and the circulating replenishing switching valve 31 is connected with the liquid inlet of the auxiliary oil tank 9 through a return branch.
The upper part of the test oil tank 1 is provided with a liquid level controller 33 and a breathing filter 34 with a drying function; the upper part of the water tank 24 is provided with a liquid level controller and a breathing filter with a drying function; the upper part of the auxiliary oil tank 9 is provided with a liquid level controller and a breathing filter with a drying function.
The working principle of the invention is as follows:
firstly, a tested filter is placed into a testing device, a tested tube switching valve is switched to a backflow branch, a water flow regulating valve is cut off, an oil flow regulating valve is opened, test media in a test oil tank are subjected to continuous purification treatment through circulation, water content test is conducted on a background, if the water content is not met, the water content needs to be purified and removed continuously, if the water content needs to be met, the tested tube switching valve is switched to the tested filter, the tested filter is fully filled with test media at a small flow rate, air in the tested filter is discharged, the tested tube switching valve is switched to the backflow branch, a test pump is started, the water flow regulating valve and a water injection pump are started, the water injection pump and a bypass pump are regulated according to test parameters, the pressure difference of the water dispersing device is regulated to be within a required range, then an upstream sampling valve is used for sampling whether the water concentration meets the requirement or not, after the water concentration meets the requirement, the tested filter is switched to one side of the tested by the tested tube switching valve, test timing is started, and the corresponding sampling test is conducted until the test is finished after the specified time or the test requirement is met.
The invention is characterized in that:
1. because shutdown and other operations can cause certain influence to the system, and then influence the fluctuation of water concentration, specially designed by test tube way switching valve, direct mount is tested the filter after background water concentration reaches the standard, and regulation water concentration does not need to shut down after reaching the standard and installs by the test piece, and direct switch is just can test by test tube way switching valve.
2. The oil collecting tank system can bring a certain amount of test media to flow out due to replacement and sampling, meanwhile, particle pollution and air contact are caused by contact of tools, table boards and the like, if the test media directly return to the test oil tank, the test media can cause the fluctuation of the bottom water of the test media, and after passing through the oil collecting tank purifying filter and the oil collecting tank dewatering filter through the oil collecting tank auxiliary pump, the test media basically reach the standard, so that the purposes of meeting test requirements and saving cost are achieved.
3. If the tested filter has poor water separation effect, the background water content of the test medium can be directly influenced, the upstream water concentration is further influenced, and finally the test result is influenced, so that an auxiliary oil tank is added, and the factors are avoided, and the specific working principle is as follows: the test medium of the test loop returns to the auxiliary oil tank, the test medium is circularly purified and dehydrated all the time under the action of the auxiliary purifying and supplementing pump, when the liquid level of the test medium in the test oil tank is lower than a certain limit, a liquid level controller sends out a signal, at the moment, a circulating supplementing and switching valve works to switch the valve to one side of supplementing, and then the test medium is sent to the test oil tank through a dehydrating filter for guaranteeing delivery, when the liquid level reaches a set position, the liquid level controller sends out a signal, and the circulating supplementing valve is switched to one side of circulating; when the liquid level of the auxiliary oil tank reaches the upper limit, the liquid level controllers send out signals, at the moment, the circulation replenishment valve is opened to actively replenish test media for the test oil tank, and when the liquid level of the auxiliary oil tank reaches the lower limit, the circulation replenishment switching valve is switched back to the circulation side, and the two liquid level controllers mutually assist in running.
4. When the test flow of the test system is very small, the water injection rate is smaller, the stability of the water concentration is affected by the tiny fluctuation of the system pressure, but under the condition of relatively large test flow, the bypass pump is added, the bypass flowmeter is added, when the test is carried out at the smaller flow, water injection is carried out according to the stable larger flow, the mixed stable test medium is pumped into the water removal filter through the bypass pump to be split, and enters the auxiliary oil tank to circulate after being metered through the bypass flowmeter, the test flow at the moment is the main system flow minus the split flow, and the flow at the moment can be from any number larger than 0.
While the basic principles of the invention have been shown and described, there are various changes and modifications to the invention, which fall within the scope of the invention as hereinafter claimed, without departing from the spirit and scope of the invention.

Claims (2)

1. A filter oil-water separation efficiency test system is characterized by comprising a test oil tank unit, a water tank unit, a test unit and an auxiliary oil tank unit, wherein an oil outlet of the test oil tank in the test oil tank unit is sequentially connected with a test pump, a heat exchanger, an oil flow regulating valve, an oil flowmeter, an upstream water dispersing device, a tested filter, a downstream water dispersing device and a liquid inlet of the auxiliary oil tank in the auxiliary oil tank system through pipelines, the pipelines between the heat exchanger and the oil flow regulating valve are connected with an oil inlet of the test oil tank through an oil return pipeline, the oil return pipeline is provided with a test system pressurized overflow valve, a thermometer is arranged on a pipeline between the oil flow regulating valve and the flowmeter, a background sampling valve is arranged on a pipeline between the oil flowmeter and the upstream water dispersing device, pressure gauges are respectively connected at two ends of the upstream water dispersing device, the tested filter and the downstream water dispersing device in parallel through pipelines, the two ends of the tested filter are connected in parallel with a return branch through a tested pipeline switching valve, an upstream sampling valve and a system pressure gauge are sequentially arranged on a pipeline between the upstream water dispersing device and the tested filter, the pipeline between the upstream sampling valve and the system pressure gauge is connected with an auxiliary oil tank liquid inlet through a shunt bypass, the shunt bypass is sequentially provided with a switching valve, a bypass pump, a bypass water removing filter and a bypass flowmeter, a downstream sampling valve is sequentially arranged on the pipeline between the downstream water dispersing device and the auxiliary oil tank, the bottoms of the background sampling valve, the upstream sampling valve and the downstream sampling valve are provided with an oil collecting tank, the oil collecting tank is connected with the auxiliary oil tank liquid inlet through a liquid return pipeline, the oil collecting tank purifying filter and the oil collecting tank water removing filter are sequentially arranged on the liquid return pipeline, and a water outlet of a water tank in a water tank unit is sequentially connected with a water injection pump through a pipeline, the water flow regulating valve, the water flow meter and the upstream water dispersing device are connected, a pipeline between the water injection pump and the water flow regulating valve is connected with a water inlet of the water tank through a water return pipeline, the water return pipeline is provided with a pressurized overflow valve, a liquid outlet of an auxiliary oil tank in the auxiliary oil tank system is sequentially connected with an auxiliary purifying and replenishing pump, a front water removing filter, a circulating replenishing switching valve, a rear water removing filter and an oil inlet of a test oil tank through pipelines, and the circulating replenishing switching valve is connected with the oil inlet of the test oil tank through a backflow branch
Is connected with a liquid inlet of the auxiliary oil tank; the upper part of the test oil tank is provided with a liquid level controller and a breathing filter with a drying function; the upper part of the water tank is provided with a liquid level controller and a breathing filter with a drying function.
2. The filter oil-water separation efficiency test system according to claim 1, wherein: the upper part of the auxiliary oil tank is provided with a liquid level controller and a breathing filter with a drying function.
CN201811578416.6A 2018-12-24 2018-12-24 Filter oil-water separation efficiency test system Active CN109444022B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201811578416.6A CN109444022B (en) 2018-12-24 2018-12-24 Filter oil-water separation efficiency test system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201811578416.6A CN109444022B (en) 2018-12-24 2018-12-24 Filter oil-water separation efficiency test system

Publications (2)

Publication Number Publication Date
CN109444022A CN109444022A (en) 2019-03-08
CN109444022B true CN109444022B (en) 2023-12-22

Family

ID=65537849

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201811578416.6A Active CN109444022B (en) 2018-12-24 2018-12-24 Filter oil-water separation efficiency test system

Country Status (1)

Country Link
CN (1) CN109444022B (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5965015A (en) * 1998-11-09 1999-10-12 Whatman Inc. Oil-water separator system with oleophobic fibrous filter
CN104502131A (en) * 2014-12-15 2015-04-08 安徽江淮汽车股份有限公司 Performance testing system for suction filter of speed changing box
CN205665143U (en) * 2016-05-11 2016-10-26 山西惠欣特矿山机电科技有限公司 Detection apparatus for mining emulsion back flush filter core filtering quality
CN207557038U (en) * 2017-10-31 2018-06-29 潍柴动力股份有限公司 A kind of separative efficiency test device of oil-gas separating device for engine
CN108862468A (en) * 2018-06-25 2018-11-23 哈尔滨工程大学 A kind of oil-water separation test device by gravity reflux
CN209342576U (en) * 2018-12-24 2019-09-03 新乡天翼过滤技术检测有限公司 A kind of filter water-oil separating efficiency test system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5965015A (en) * 1998-11-09 1999-10-12 Whatman Inc. Oil-water separator system with oleophobic fibrous filter
CN104502131A (en) * 2014-12-15 2015-04-08 安徽江淮汽车股份有限公司 Performance testing system for suction filter of speed changing box
CN205665143U (en) * 2016-05-11 2016-10-26 山西惠欣特矿山机电科技有限公司 Detection apparatus for mining emulsion back flush filter core filtering quality
CN207557038U (en) * 2017-10-31 2018-06-29 潍柴动力股份有限公司 A kind of separative efficiency test device of oil-gas separating device for engine
CN108862468A (en) * 2018-06-25 2018-11-23 哈尔滨工程大学 A kind of oil-water separation test device by gravity reflux
CN209342576U (en) * 2018-12-24 2019-09-03 新乡天翼过滤技术检测有限公司 A kind of filter water-oil separating efficiency test system

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
影响燃油滤清器油水分离效率准确性的因素;王秉杰;;内燃机与配件(第02期);24-28 *
潜油电泵油气分离器性能测试***研制;于洪英;;石油矿场机械(第03期);72-75 *

Also Published As

Publication number Publication date
CN109444022A (en) 2019-03-08

Similar Documents

Publication Publication Date Title
CN109444023B (en) Oil-water separation efficiency test system
CN114212927B (en) Device and method for recycling slice wastewater
CN203764143U (en) Device for testing reverse osmosis membrane elements and nanofiltration membrane elements in batches
CN206168250U (en) Reverse osmosis membrane performance detection device
CN109444022B (en) Filter oil-water separation efficiency test system
CN202185260U (en) Positive osmosis device
CN103293011B (en) A kind of test system for testing rotator type energy recycle device
CN110203895A (en) A kind of the circulatory purification system and circulatory purification method of helium
CN209342576U (en) A kind of filter water-oil separating efficiency test system
CN205953660U (en) High flux microgrid dynamic membrane bioreactor
CN201991035U (en) Constant current water supply apparatus
CN213656289U (en) Intelligent lubricating oil purification device
CN204369707U (en) The coal-based F-T synthesis water of a kind of indirect liquefaction is separated cleaning treatment system
CN210410242U (en) High pressure STRO membrane element testing arrangement
CN210303550U (en) Intelligent blending system for ethanol for cannabinoid extraction
CN204731064U (en) A kind of near infrared spectrum on-line period system
CN110624702B (en) Intelligent centrifugal oil purifier
CN111471498A (en) Desulfurization integrated device and desulfurization method for accurately controlling injection amount of desulfurizer
CN208152145U (en) A kind of novel non-negative pressure frequency-changing water supply device
CN102580372A (en) Coal slime filter-press test system and coal slime test method
CN202297430U (en) Plasma protein ultrafiltration membrane device
CN206116532U (en) Mixing arrangement of battery solution solvent
CN205773772U (en) Water-jet loom wastewater treatment recycling device
CN215263382U (en) Intelligent gas concentration detection device
CN208500876U (en) A kind of self-produced fuel gas pretreatment unit of CONTINUOUS REFORMER

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant